Bhagya

Teachers recommend solving Kerala Syllabus Plus Two Economics Previous Year Question Papers and Answers Pdf March 2021 to improve time management during exams.

Kerala Plus Two Economics Previous Year Question Paper March 2021

Answer question from 1 to 41 up to the maximum of 80 scores. (12 × 1 = 12)

Question 1.
a. In a centrally planned economy, all the important economic activities are planned by:
i) The market
ii) The government
iii) Both market and government
iv) Corporate sector
Answer:
ii) The government

b. An example of micro variable is:
i) National income
ii) Gross Domestic Product
iii) Net Domestic Product
iv) Individual income
Answer:
iv) Individual income

c. The founding father of Modern Economics is:
i) J.M. Keynes
ii) Adam Smith
iii) Alfred Marshall
iv) Amartya Sen
Answer:
ii) Adam Smith

d. The book ‘General Theory of Employment, Interest and Money was published in the year:
i) 1929
ii) 1936
iii) 1775
v) 1946
Answer:
ii) 1936

e. Other things remain the same, when price of a commodity decreases, ite demand
i) Falls
ii) Rises
iii) Never changes Constant
Answer:
ii) Rises

f. The firm’s revenue under perfect competiion is:
i) MR > AR
ii) AR > MR
iii) MR = AR
iv) MR > Price
Answer:
iii) MR = AR

g. National income in India is:
i) GDP_MP
ii) GNP_FC
iii) NDP_FC
iv) NNP_FC
Answer:
iv) NNP_FC

h. In India, the custodian of foreign exchange reserve is :
i) State Bank of India
ii) Reserve Bank of India
iii) Canara Bank
iv) Indian Bank
Answer:
ii)  Reserve Bank of India

i. The situation where, market demand equals market supply:
i) Excess supply
ii) Excess demand
iii) Equilibrium
iv) Deficient demand
Answer:
iii) Equilibrium

j. Shape of the demand curve under monopoly market:
i) Upward sloping
ii) Downward sloping
iii) Horizontal straight line
iv) Vertical straight line
Answer:
ii) Downward sloping

k. Budget in which Government Expenditure is greater than Government Revenue:
i) Surplus budget
ii) Deficit budget
iii) Balanced budget
iv) Current account deficit
Answer:
ii) Deficit budget

l. In a two sector model AD = \(\overline{\mathrm{C}}+\overline{\mathrm{I}}\)
Here autonomous consumption is indicated by:
i) c
ii) \(\overline{\mathrm{C}}\)
iii) \(\text { T }\)
iv) Y
Answer:
ii) \(\overline{\mathrm{C}}\)

Question from 2 to 13 carry each.

Question 2.
Write any two features of centrally planned economy.
Answer:
Welfare motive or welfare of the people, No private property, govt, planning, govt takes all important decisions etc.

Question 3.
What do you mean by Balance of trade?
Answer:
Difference between value of visible exports and visible imports of goods of a country in a given period of time.

Question 4.
What is meant by Average product and Marginal product?
Answer:
AP = Total Product per variable input or AP = TP/ variable input MP = Change in output/change in input or MP = “TP/”variable input.

Question 5.
What is Cardinal utility analysis?
Answer:
The level of utility can be expressed in numbers or utility can be measured cardinally . Eg:- 50 utils etc.

Question 6.
List out four sectors of the economy according to the marco economic point of view.
Answer:
Household, Firms or Business, Government, External or Foreign Sector.

Question 7.
What is the difference between micro and macro economics?
Answer:
Microeconomics deals with individual behaviour, Macroeconomics with aggregates.

Question 8.
Why the AR and MR curves are the same under per-fect competition?
Answer:
Under Perfect competition, there is uniform price, soAR = MR.

Question 9.
What do you mean by Excess demand?
When total demand is greater than total supply in a market or Total demand>Total supply.

Question 10.
What is meant by Paradox of thrift?
Answer:
If the MPS of the economy increases, the total value of saving in the economy will not increase or If the individual saving increases, the total saving in the economy will not increase.

Question 11.
Briefly explain the market demand.
Answer:
Sum total of individual demand for a good in a particular market at different prices.

Question 12.
Define the Gross national Product.
Answer:
The economic output produced by a nation’s normal residents. They are either in India or in abroad. Or GDP + Net Factor income from abroad = GNP or GNP = NNPmp + Depreciation.

Question 13.
What is meant by the personal income?
Answer:
PI = Nl -Undistributed profit -Net interest payment made by household – corporate tax + Transfer payment to household.

Question 14.
Write a brief note on the central problems of an economy due to scarcity of resources.
Answer:
What is produced and in what quantities? How are these goods produced? For whom are these goods produced?

Question 15.
Write a short note to the Great Depression of 1929.
Answer:
Started in USA, output and employment level in Europe and North America fell by huge amount, many factories were closed or shut down, production fell, huge unemployment, shut down of industries.

Question 16.
Briefly explain the circular flow of income in a simple economy.
Answer:

Question 17.
Identify the important features of monoploy market.
Answer:
Single seller, No close substitute, No entry , price maker, downward sloping demand curve.

Question 18.
Briefly explain any three functions of money.
Answer:
Medium of exchange, Unit of account, Measure

Question 19.
Briefly explain the determination of income in a two sector model.
Answer:

Question 20.
Define the Total Revenue, Average Revenue and Marginal Revenue.
Answer:
TR = total amount of receipts from the sale of the product or TR = Price X output AR = Revenue per unit of commodity sold or AR = TR/QMR = net addition to TR when an additional unit sold or MR =TR_n – TR_n-1; , or MR = ∆TR/∆Q (Since in the Malayalam version to the question, it is asked to define TP, AP and MP, give score 1 + 1 + 1, if the student defines or write the equations to TP, AP and MP.) TP – quantity produced by using a given level of output AP – Output per unit of variable input or TP/variable input MP – change in output/change in input.

Question 21.
When price is ₹10/-, the consumer buys 10 units of commodity. When price rises to ₹20/-, the demand falls to 5 units. Calculate the price elasticity of de-mand.
Answer:
For equation or formula(relevant formula)For correct process For answer (-0.5 or 0.5)∆q/∆p x p/q – 10/10 × 5/10 = – 0.5.

Question 22.
Discuss the important determinants of firm’s supply curve.
Answer:
1. Technological progress
2. input price
3. unit tax

Question 23.
Explain the difference between Revenue deficit and Primary deficit.
Answer:
Revenue Deficit = Revenue Expenditure – Revenue Receipts Primary Deficit = Fiscal Deficit-Net interest payment.

Question 24.
Explain any two features of indifference curve.
Answer:
1. For writing any two features( downward sloping or convex to origin, Higher IC shows higher level of satisfaction and lower IC shows lower level of satisfaction, two ICs never intersect each other)
2. For explanation or figure/diagram

Question 25.
Analyse the features of Perfect competition.
Answer:
Large number of buyers and sellers, Homogeneous product, free entry and exit, price taker, uniform price, perfect knowledge, demand curve parallel to X axis, No transport cost etc.

Question 26.
Define the concepts of stocks and flows with examples.
Answer:
Stocks:- A quantity or variable measured at a particular point of time or static concept. Eg;- Capital, wealth etc. FlowsA quantity or variable measured at particular period of time or dynamic concept. Eg;- Capital formation, income etc.

Question 27.
Distinguish between MPC (Marginal Propensity to Consume) and MPS (Marginal Propensity to Save).
Answer:
MPC = Change in consumption/Change in income or AC/AY or any relevant equation or definition. MPS = Change in saving /Change in income or AS/AY.

Question 28.
What do you mean by the government budget. Explain its objectives.
Answer:
Annual financial statement of the govt. Statement of estimated receipts and expenditure of the govt, for a financial year. Objectives:- Allocation function Redistribution function Stabilisation function Relevant.

Question 29.
What is an open economy? identify the three linkages of an open economy.
Answer:
Relevent definition to open economy (Is one which interacts with other countries through various channels or country having economic relations with other countries) Three linkages:- Output or product market linkage Financial market linkage Labour or Factor market linkage

Question 30.
Suppose the market demand curve of Apple is ; QD = 500 – P. The market supply curve of Apple is; qs = 100 + P. Calculate the equilibrium price and quantity.
Answer:
At equilibrium, Qd = Qs or Qs = Qd 100 + p =500 – p 2p = 400 P = 200 Equi.
Price = 200 100 + p = 100 + 200 = 300
500 -p = 500 “200 = 300 Equi. Quantity ” = 300

Question 31.
List out the important features of monopolistic competition; write two examples of this market.
Answer:

1. Any three features of Monopolistic competition (many firms or fairly large number of firms, differentiated products or non-homogeneous products, free entry and exit, selling cost etc)
2. Any two relevant examples (soap producing firms, Toothpaste producing firms etc).

Question from 32 to 37 carry 5 scores each. (6 × 5 = 30)

Question 32.
Explain price ceiling. Write its two effects.
Answer:
1. Pnceceing :-Thegovernmentimposed upperlimit on the price of a good or services. Fixed below the market determined price. When the government fixes a price ceiling there is an excess demand. Effects :- Rationing, Long queue, creation of black marketing etc.

Question 33.
Classify the following Govt. Expenditures into Revenue Expenditure and Capital Expenditure.
Answer:
Revenue Expenditure: lnterest Payments, Subsidies, Salaries and Pensions Capital Expenditure:- lnvestment in shares, Loans to state Govt. by central govt.

Question 34.
The items in Column A show the concepts related with cost and production. Match them suitably with Coulmn B.

A	B
Short run	Total cost
Marginal product	Some factors are fixed
Total Fixed Cost	ATC
Curve(TFC)	AQ
Total Fixed Cost + Total Variable Cost (TFC + TVC)	Change in output Change in input
Marginal Cost (MC)	Horizontal Straight line parallel to X axis

Answer:
Short run – Some factors are fixed Marginal Product Change in output/change in input Total Fixed Cost Curve(TFC) – Horizontal stright lineparallel to X axis. Total Fixed Cost + Total Variable Cost(TFC + WC) – Total Cost Marginal Cost(MC) – ∆TC/∆Q.

Question 35.
What is Balance of payments (BOP)? Explain the three components of current account of BOP.
Answer:
BoP:-Record the transactions in goods, services and assets between a country with the rest of the world for a specified period, typically a year. Components of current a/c:- Trade in goods, Trade in services, Transfer payments & with brief explanation.

Question 36.
Explain the tax revenue and non-tax revenue of the Central Government.
Answer:

1. Tax Revenue :-Direct Tax and Indirect Tax
2. Direct Tax :- Personal income tax, Corporate tax, wealth tax etc (any two examples)
3. Indirect Tax:- Customs duty, excise duty, GST, etc (any two)
4. Non Tax Revenue :- interest receipts, dividends, profits, fee, grants in aid etc.

Question 37.
Brsefly explain ‘the Returns to scale’.
Answer:
Long run production function/Studies the effects of increase in factors in same ratio on the output (or any relevant point which clarifies the concept) 3 stages of Returns to scIe :- IRS, CRS and DRS

Questions from 38 to 41 carry 8 scores each.

Question 38.
A consumer wants to consume two goods. The prices of two goods are 10/- each. Income of the consumer is 50f-. based on the data:
A) Draw a budget line.
B) Explain the optimal choice of the consumer with the help of indifference curve.
Answer:
A. M/p1 = 50/10 = 5M/p2 = 50/10 = 5
Budget line Diagram with given data and the Budget Equation

B. Diagram and explanation

Question 39.
Complete the given table and define The concepts of TFC, WC and TC.

Output	TFC	TVC	TC	AFC	AVC	SAC	SMC
0	100	0
1	100	100
2	100	200
3	100	300
4	100	400

Answer:

Output	TFC	TVC	TC	AFC	AVC	SAC	SMC
0	100	0	100	–	–	–	–
1	100	100	200	100	100	200	100
2	100	200	300	50	100	150	100
3	100	300	400	33.3	100	133.3	100
4	100	400	500	25	100	125	100

TFC – The total cost to employ fixed inputs or TC – TVCTVC- Total cost to employ variable inputs or TC – TFCTC – Total cost of the firm or TFC + TVC = TC

Question 40.
GDP of a country can be calculated by using three methods. Explain the income and expenditure method.
Answer:

1. For explaining income method(W + P + ln + R)
2. For explain Expenditure method(C + l + G + X M)

Question 41.
The Reserve Bank of India (RBI) controls the money supply in the economy in various ways. Explain. (Hints : Quantitative and Qualitative tools)
Answer:

1. For Quantitative Measures – Bank Rate, CRR, Open Market Operation etc. (any relevant three measures with explanation)
2. For listing any two qualitative measures persuasion, moral suasion, margin requirement etc.

Teachers recommend solving Kerala Syllabus Plus Two Economics Previous Year Question Papers and Answers Pdf March 2022 to improve time management during exams.

Kerala Plus Two Economics Previous Year Question Paper March 2022

Part – I

A. Answer any 4 questions from 1 to 6. Each caries 1 Score. (4 × 1 = 4)

Question 1.
The book ‘General Theory of Employment, Interest and Money1 was written by
a) Adam Smith
b) Alfred Marshall
c) J.M. Keynes
d) David Ricardo
Answer:
Total revenue and total cost

Question 2.
Profit is the difference between
a) Total Revenue and Total Cost
b) Total Revenue and Total Variable Cost
c) Total Revenue and Total Fixed Cost
d) Marginal Revenue and Marginal Cost
Answer:

Question 3.
At the Break-even-point, the firm faces
a) Super normal profit
b) Normal profit
c) Abnormal profit
d) Loss
Answer:
Normal profit

Question 4.
The want satisfying capacity of a commodity is known as
a) Demand
b) Supply
c) Utility
d) Elasticity of demand
Answer:
utility

Question 5.
Which one of the following is a Stock Variable?
a) Wealth
b) Income
c) Investment
d) GDP
Answer:
wealth

Question 6.
Which of the following is included in the current ac-count of balance of payment (BOP)?
a) External borrowing
b) Purchase of assets
c) Foreign Direct Investment
d) Trade in goods
Answer:
Trade in goods

B. Answer all questions from 7 to 10. Each carries 1 score. (4 × 1 = 4)

Question 7.
The market with a few sellers is known as:
a) Perfect competition
b) Oligopoly
c) Monopolistic competition
d) Monopoly
Answer:
oligopoly

Question 8.
The price elasticity of the following demand curve is.

a) e^D > 1
b) e^D < 1
c) e^D = a
d) e^D = 0
Answer:
c) e^D = a

Question 9.
In a perfectly competitive market with free entry and exit, the equilibrium price is
a) equal tomin AC
b) greater than AC
c) less than AC
d) equal to min MC
Answer:
Equal to minimum of AC

.

Question 10.
The ratio of nominal GDP to real GDP is
a) Consumer Price Index
b) Wholesale Price Index
c) GDP Deflator
d) Producer Price Index
Answer:
GDP Deflator

Part – II

A. Answer any 3 questions from 11 to 15. Each carries 2 scores. (3 × 2 = 6)

Question 11.
Write two examples for substitute goods and complementary goods.
Answer:

• Examples for substitute goods are
  1. Tea and coffee
  2. Eye glasses and contact lenses.
• Examples for complementary goods are
  1. Car and petrol
  2. Bread and butter

Question 12.
Distinguish between short-run and long-run in the production process.
Answer:
Under short run only one factor is variable all other factors are fixed, in long run all factors are variable.

Question 13.
What do you mean by market equilibrium?
Answer:
Market equilibrium is a point where the market supply equals market demand.

Question 14.
Elucidate intermediate goods with example.
Answer:
Goods used as an input for producing new goods are called intermediate goods. For example wheat is an intermediate good in case of a bread making company.

Question 15.
Write the appropriate economic term for the following:
a) The rate of change of consumption as income changes.
b) The rate of change of saving as income changes.
Answer:
(a) Marginal propensity to consume (MPC)
(b) Marginal propensity to save (MPS)

B. Answer any 2 questions from 1.6 to 18. Each caries 2 scores. (2 × 2 = 4)

Question 16.
List the major sectors in an economy according to the macro economic point of view)
Answer:
According to Macro economic point of view the different sectors arei:

1. Firms
2. Households
3. Government
4. External sector.

Question 17.
When the price of Apple increased by 20 percent, the quantity supplied of Apple increased by 30 percent. Calculate the price elasticity of supply.
Answer:

Question 18.
Mention two motives behind the demand for money.
Answer:
Money is demanded for many purposes, but it is mainly demanded for:

1. Transaction purposes
2. Precautionary motive.

Part – III

A. Answer any 3 questions from 19 to 23. Each caries 4 scores. (3 × 4 = 12)

Question 19.
Distinguish between centrally planned economy and ‘ market economy.
Answer:
(a) Centrally planned economy – It is an economic system where all means of production are under the ownership and control of the government. This economy otherwise known as socialist economy.

(b) Market economy – Under this system all means of production are under the ownership and control of private individuals. This economy is otherwise known as capitalist economy.

Question 20.
What are the main functions of money?
Answer:
Money plays an important role in the modern world. The vital role played by money can be termed as functions of money. They are

• Primary functions
  1. Medium of exchange
  2. Measure of value
• Secondary functions
  1. Store of value
  2. Standard of differed payment
  3. Transfer of value
• Contingent functions
  1. Basis of credit
  2. Liquidity
  3. Distribution of Nationalincome
  4. Guarantor of solvency

Question 21.
(a) List the characteristics of monopoly market.
(b) Draw the average revenue and marginal revenue curves of the monopoly market.
Answer:
Monopoly is a market situation where one seller or producer of the commodity exists. The main features of monopoly market are given below.
a)

1. Single seller for a product
2. Absence of substitute products
3. Entry of new firms in the market is denied
4. Monopolist has complete control over supply of the product.
5. Firm and industry are the same
6. Firm is price maker

b) Average revenue and Marginal revenue curves under monopoly

Here MR curve lies below AR curve

Question 22.
Equilibrium output and aggregate demand are deter-mined in the following diagram:
(a) Identify the components of Aggregate Demand.
(b) Show the changes in the equilibrium when au-tonomous expenditure increases.
Answer:
a) Aggregate demand consists of autonomous expenditure (A), Marginal propensity to consume (c) and income (y)

A rise in autonomous expenditure will result in an upward parallel shift in AD which result in a new equilibrium E₁ here income increases from y to y₁

Question 23.
Explain the objectives of government budget.
Answer:
Budget is an annual financial statement of income

B. Answer any 1 Question from 24 to 25. Carries 4 scores. (1 × 4 = 4)

Question 24.
(a) Draw Marginal Product Curve and Average product curve in a single diagram.
(b) Identify any two relationship between them.
Answer:

b) Relationship between AP and MP
1. When a AP increases, MP is greater than AP ie. MP curve is above the AP curve.
2. When AP reaches maximum AP and MP are equal.

Question 25.
Match the following:

A	B
GDPat Factor Cost	NDPFO + NFIA
NNPat Factor Cost	GDPMP – Depreciation
NDPat Market Price	GNPMP – Depreciation
NNPat Market Price	GDPMP – Net indirect Tax

Answer:

A	B
GDP at factor cost	GNPMP – Depreciation
NNP at factor cost	GDPMP – Depreciation
NDP at market price	NDPFO + NFIA
NNP at market price	GDPMP – Net indirect Tax

Part – IV

A. Answer any 3 questions from 26 to 29. Each carries 6 scores. (3 × 6 = 18)

Question 26.
(a) Complete the short-run costs table.

Output	TFC	TVC	TC	SAC	SMC
0	20	0		–	–
1	20	20
2	20	30
3	20	34
4	20	40
5	20	60
6	20	100

(b) Draw SAC and SMC curves in a single diagram,
Answer:

Output	TFC	TVC	TC	SAC	SMC
0	20	0	20	–	–
1	20	20	40	40	20
2	20	30	50	25	10
3	20	34	54	18	4
4	20	40	60	15	6
5	20	60	80	16	20
6	20	100	120	20	40

TC = TVC + TFC, SAC = \(\frac{\mathrm{TC}}{\mathrm{Q}}\)
SMC = \(\frac{\Delta T C}{\Delta Q}\)
Q → output

Question 27.
Distinguish Price Ceiling and Price Floor with the help of diagrams.
Answer:
‘Price ‘ceiling’
It is the upper limit on the price of goods and services imposed by the government to protect the interest of consumers (ie. protection from high price)

Here in the diagram P₀ is equilibrium price which is higher, P_c is the ceiling price fixed by government which is lower than P₀.

‘Price floor’
It is otherwise known as support price, it is the minimum price fixed by government to protect the interest of the producers.

Here in the diagram P0 is equilibrium price which is very low. To ensure fair price government fixes floor price above the equilibrium price (P0). It is the floor price.

Price ceiling:	Price floor:
Upper price limit imposed by government	Lower price limit imposed by „ government
It is less than equilibrium price	It is higher than equilibrium price
This will create excess demand	This will create excess supply
Imposed on necessary commodities	Generally imposed on agricultural goods

Question 28.
Differentiate the following with examples:
1. Revenue Receipts and Capital Receipts.
2. Revenue Expenditure and Capital Expenditure.
Answer:
a) Revenue receipts:
The receipts which do not create liabilities or reduce government assets are known as revenue receipts.

1. Capital receipts:
   The receipts that create liabilities or reduce the assets of the government.

b) Revenue expenditure:
Expenditure that does not create assets or reduce liabilities is called revenue expenditure.

1. Capital expenditure:
   Expenditure which creates assets or reduces liabilities is known as capital expenditure.

Question 29.
(a) What do you mean by Exchange Rate?
(b) Briefly explain Flexible Exchange Rate and Fixed , Exchange Rate.
Answer:
a) Exchange rate: It is the rate at which one currency is exchanged for another currency.

b) Fixed exchange rate : It is otherwise known as pegged exchange rate. Here the exchange rate is fixed by government or central bank.

Flexible exchange rate:
This exchange rate is otherwise known as floating exchange rate. Here exchange rate is fixed by farces of demand and supply.

B. Answer any 2 questions from 30 to 32. Each carries 6 scores. (2 × 6 = 12)

Question 30.
Explain the monetary policy tools of RBI to control money supply in the Indian Economy.
Answer:
Monetary policy:
It is the policy franked and implemented by the central bank, through this policy money supply is regulated according to various situations. For this central bank uses certain tools, they are given below.
1. Bank rate
2. Reserve ratios
3. Open market operations.

1. Bank rate:
It is the rate of interest paid by commercial banks on short term loans borrowed from RBI. An increase in bank rate will result in contraction of credit this would help to control inflation. On the other hand a decrease in bank rate will result in expansion of credit, this would help to overcome depression.

2. Reserve ratios:
This include CRR and SLR cash Reserve Ratio (CRR) statutory Liquidity Ratio (SLR) Reserve bank increases both CRR and SLR to control inflation, to control depression reserve bank reduces both CRR and SLR.

3. Open market operations.:
Purchase and sale of government securities by the RBI is known as open market operations. To control inflation RBI sells securities this would reduce the volume of credit provided by commercial banks, Because commercial banks purchase the securities issued by RBI with their loanable funds. To control depression RBI , purchases securities sold earlier. So the money comes back to commercial banks, with this the credit supply increases.

Question 31.
(a) Compare Open Economy and Closed Economy.
(b) Explain the three ways in which an economy interact with rest of the world.
Answer:
Open economy
An economy which has economic relations with other countries of the world through exchanging goods and services, financial assets etc…

1. Product market linkage : Country can import and export goods. This will result in more global co-peration.
2. Financial market linkage : Through this investors can invest in domestic economy as well as in other countries.
3. Factor market linkage : This means factors can be easily transfer-from one nation to another nations. This process improved the connection of different nations.

Question 32.
Observe the following diagram:
Answer:
a) When income change from 50 to 70

When income increased from 50 to 70 the budget line shifts upward, b. When price

when price

when price of x₁ decreased, the x intercept moves forward from 5 to 10, there is no change in y intercept.

Part – V

Answer any 2 questions from 33 to 35. Each carries 8 scores. (2 × 8 = 16)

Question 33.
a) What are the features of indifference curve?
b) Diagrammatically explain the optimal choice of the consumer.
Answer:
i) Indifference curve
It is the locus of points of combinations of two goods which give same level of satisfaction to the consumer.

Features of indifference curve.

1. Indifference curve slopes downwards from left to right.
2. Indifference curve ¡s convex to origin.
3. Higher indifference curves represent higher levels of satisfaction.
4. Indifference curves do not intersect each other

ii) Optimal choice of the consumer A consumer prefers a situation where his satisfaction is maximum. According to indifference curve approach, a consumer attains equilibrium at the point where budget line is tangent to highest possible indifference curve.

Here in the diagram point ‘E’ shows optimal choice of the consumer.

Question 34.
a) Identify the three methods of measuring National Income.
b) Explain any two methods of measuring National Income.
Answer:
Money value of all final goods and services produced by a nation during a financial year is known as national income.  Computation of national income is an important activity. To compute national income we can use three different methods they are

1. Product method or value added method
2. Expenditure method or out lay method
3. Income method

b) 1. Product method or value added method:
Here in this method national income is calculated by adding all the final goods and services produced by all production units in a nation during a financial year. But it is not so easy because the final output produced by a firm is used as input in other firms this problem is termed as double counting. To avoid this problem value added method is used to calculate final value of output. As per value added method, GDP is the sum of gross value added by all the producers in the domestic territory.

2. Income method:
Under his method GDP is calculated by adding together all the factor income received by the owners of factors of production, such as land, labour, capital and entrepreneurship. Therefore as per income method the GDP of an economy is the sum total of wages, rent, interest and gross profit.
ie.GDP = W+R+l+P

Question 35.
a) What are the features of a perfect competitive market?
b) Diagrammatically explain the profit maximisation conditions of perfect competitive firm in the short- run.
Answer:
Perfect competition:
It is a market situation where large number of buyers and sellers operate freely perfect competition is an extreme form of market which is rarely existing in the real world.

Features of perfect competition.

1. Large number of buyers and sellers
2. Homogenous products.
3. Perfect mobility of factors of production
4. Perfect knowledge of market condition
5. Freedom of entry and exit
6. Absence of transport cost
7. Uniform price
8. Absence of selling cost
9. Firms are price takers.

Short run equilibrium Conditions of equilibrium.

1. P = MC
2. MC curve should cut MR curve from below.
3. Price should be greater than or equal to AVC

Diagrammatic representation of equilibrium

The above given diagram represents short run equilibrium under perfect competition.
Here TR = OPAQ
TC = OEBQ
Profit = TR – TC
le. OPAQ – OEBQ = EPAB

Teachers recommend solving Kerala Syllabus Plus Two Economics Previous Year Question Papers and Answers Pdf March 2023 to improve time management during exams.

Kerala Plus Two Economics Previous Year Question Paper March 2023

Answer any 8 questions from 1 to 10. Each carries 1 score:

Question 1.
A good that is non-rival and non-excludable is
(a) Public goods
(b) Inferior goods
(c) Private goods
(d) Capital goods
Answer:
Public goods

Question 2.
The value of Marginal Propensity to Consume (MPC) lies between
(a) 0 and 100
(b)0and1
(c) -1 and +1
(d) 0 and infinity
Answer:
0 and 1

Question 3.
‘For whom to produce’ is the problem related to
(a) Technology of production
(b) Selection of Goods and Services
(c) Distribution of National Income
(d) Price Determination
Answer:
Distribution of National Income

Question 4.
The short run shut-down point of a firm in a perfect competitive market is:
(a) Price = Average Cost
(b) Price = Total Cost
(c) Price = Total Variable Cost
(d) Price = Average Variable Cost
Answer:
rice = Average Variable Cost

Question 5.
The institution that regulates the money supply in India:
(a) NABARD
(b) RBI
(c) WTO
(d) SEBI
Answer:
RBI

Question 6.
If consumer’s income increases, the demand for in-ferior goods
(a) Increase
(b) Constant
(c) Decrease
(d) None of these
Answer:
Decrease

Question 7.
The ratio of Nominal GDP to real GDP is
(a) Consumer Price Index
(b) Wholesale Price Index
(c) Producer Price Index
(d) GDP Deflator
Answer:
GDP Deflator

Question 8.
If export of goods is more than import of goods, then Balance of trade will be:
(a) Surplus
(b) Deficit
(c) Balance
(d) Zero
Answer:
Surplus

Question 9.
The U shape of Long run Average Cost (LRAC) curve is due to
(a) Law of Variable Proportion
(b) Law of Returns of Scale
(c) Law of Demand
(d) Law of Diminishing Marginal Utility
Answer:
Law of Returns of Scale

Question 10.
When output is zero,total Variable Cost (TVC) will be:
(a) Increasing
(b) Decreasing
(c) Zero
(d) One
Answer:
Zero

Answer any 4 questions from 11 to 15. Each carries 2 scroes.

Question 11.
What is intermediate goods? Give one example.
Answer:
It is a good which is used to produce a final good or a finished product. These goods are also known as producers good or intermediate good. Eg : Tyres

Question 12.
If the Cash Reserve Ratio (CRR) of an economy is 25% find the value of money multiplier.
Answer:
Money multiplier = \(\frac{1}{c r r}=\frac{1}{0.25}=\underline{\underline{4}}\)

Question 13.
Write down any two features of Indifference curve.
Answer:
It is the curve representing different combinations of two commodities that give equal satisfaction to a consumer.
Features of Indifference curve
1. Negatively sloping curve
2. Convex to origin

Question 14.
The market demand curve and the market supply curve for wheat are given below: Find the equilibrium price and quantity.
Answer:
Market Equilibrium = Q_d = Q_s Q_d = 50 – 2P,
Q_s = 10 + 2P
50 – 2 P = l0 + 2P
50 – 10 = 2P + 2P
40 = 4P
p = \(\frac{40}{4}\)
so equilibrium Price = 10
To find equilibrium quantity put the value of a P in either demand equation of supply equation.
Q_d = 50 – 2P
= 50 – 2 × 10
= 50 – 20 = 30

Q_s = 10 + 2P
= 10 + 2 × 10
= 10 + 20 = 30
Here the equilibrium quantity is 30

Question 15.
Write down any two objectives of government bud-get.
Answer:
A budget is annual financial statement related to the expected revenue and expenditure of government for a financial year.
Objectives of government budget
1. To attain economic growth
2. To establish equality (through redistribution)

Answer any 4 questions from 16 to 20. Each carries 3 scores.

Question 16.
Write down the three stages of returns to scale.
Answer:
Returns to scale refers to long run production func-tion. In long run all factors are variable, returns to scale explains how output changes according to the changes made in inputs. Here the output changes in three different ways they are as follows.
1. Increasing Returns of Scale (IRS)
2. Constant Returns to Scale (CRS)
3. Diminishing Returns to Scale (DRS)

1. Increasing returns of scale
   • A small increase in input results in a large increase in output.
2. Constant returns to scale
   • Here out put increases in the same proportion as in the input.
3. Diminishing returns to scale

• • Here a large increase in input results only in a small increase in outpout.

Question 17.
List out any three features of perfect competitive market.
Answer:
Features of perfect competition

1. Large number of buyers and sellers
2. Homogenous product
3. Perfect information

Question 18.
Jomon wants to buy rice and wheat with the money income of Rs. 120. Its market Prices are Rs. 15 and Rs. 20 respectively. Find the horizontal Intercept, vertical intercept and slope of the budget line.
Answer:
Take rice as x and wheat as y
Budget line equation = 15 x + 20 y = 120
Horizontal Intercept = 15 x = 120
x = \(\frac{120}{15}\) = 8

Vertical Intercept = 20 y = 120
y = \(\frac{120}{20}\) = 6
Slope = \(-\frac{P x}{P y}=\frac{15}{20}\) = 0.75

Question 19.
Write down the three limitations of Gross Domestic product (GDP) as an indicator of welfare, List out the three ways in which an economy makes economic relations with other economies.
Answer:
We cannot consider GDP as a good indicator of welfare due to following reasons.
1. Inequality in distribution of income:
Even if GDP of a nation is very high we can see people with low income there, so we cannot consider an increase in GDP would promote welfare of a nation.

2. GDP and non monetary exchanges:
Many of the non monetary transactions are not included in GDP: Eg: Service of housewife, Exchange of goods under barter system.

3. GDP and harmful goods:
The value of GDP increases when production increases, it includes the value of harmful prod-ucts.

Answer any 4 questions from 21 to 25. Each carries 4 scores.

Question 20.
List out the three ways in which an economy makes economic relations with other economies.
Answer:
One nation can keep economic relationship with other nation in the following ways
(1) Product Market linkage
(2) Financial market linkage
(3) Factor Market linkage

Answer any 4 questions from 21 to 25. Each carries 4 scores.

Question 21.
Explain the circular flow of income in a two-sector economy with the help of a diagram.
Answer:

• Here households provide factors of production to the firms for this firms provide factor payment.
• Firms provide goods and services required to the household and households give payment as price.

Question 22.
Write a short note on the emergence of macro eco-nomics.
Answer:
Macro economics has emerged as a new branch of economics after global economic crisis of 1928. It was the work done by J.M. Keynes acted as a cata-lyst for the growth of Macro economics. J.M. Keynes criticised classical economists for their unrealistic assumptions related to working of economic factors.

The views of classical economists were wrong and misleading and they failed to solve economic crisis. During this time Keynes published his famous book “General Theory of Employment Interest and Money” in 1936, which acted as a guide to solve the global economic crisis. Later the views of Keynes popularly known as Macro economics.

Question 23.
Write a short note on flexible exchange rate with the help of diagram.
Answer:
Under flexible exchange rate system exchange rate is determined according to changes in demand and supply of foreign exchange.

The above given diagram explains how exchange rate is determined under flexible exchange rate system. D is initial demand curve where ‘e’ is exchange rate when demand increased from D to D₁ as a result exchange rate changed from ‘e’ to e₁.

Question 24.
Explain price ceiling with the help of a diagram.
Answer:
Government Intervention in market against increas-ing price levels of essential commodities by fixing alower price than equilibrium price is known as price ceiling.

‘E’ is the equilibrium in the above given diagram where ‘e_p’ is equilibrium price. When government felt ‘e_p’ is very high and unaffordable for the poor, fixed a new price ‘C_p’ which is ceiling price and lower than ‘e_p’. Through this government protects common people from the adversities of price increase.

Question 25.
Difference between market economy andCentrally planned economy.
Answer:

• We can classify the entire economies in the world into three based on the differences in organization of economic activities, they are
  1. Market economy (Capitalist Economy)
  2. Centrally planned economy (Socialist Economy)
  3. Mixed Economy
• Market Economy (Capitalist Economy)
  1. Means of production are under the ownership of private individuals.
  2. Central economic problems are solved by mar-ket mechanism.
  3. Private property and transfer of wealth to legal heir, e. Profit is the ultimate aim.
  4. Less Government control over economic activities.
• Centrally planned economy (Socialist Economy)
  1.  All means of productions are under Government Ownership and control.
  2. Central economic problems are solved by Gov-ernment through planning.
  3. No private property, all wealths are controlled by government, so there you can see public property.
  4. Maximization of public welfare is the ultimate aim of Socialist Economy.
  5. All economic activities are controlled by government.

Question 26.
Explain the optimal choice of a counsumer (consumer’s equilibrium) with the help of a diagram.
Answer:
Optimal choice of consumer or consumer equilib-rium can be defined as the position of maximum satisfaction attained by a consumer. According to indifference curve approach a consumer attains equilibrium at the point where budget line is tangent to indifference curve. It can be expressed with the help of a diagram.

The above given diagram shows consumer equilibrium. HereAB is budget line of consumer and IC₁, IC₂ and Ic₃ are different indifference curves. Point ‘E’ is the region where highest possible indifference curve (Ic₂) tangents with budget line so that particular point (E) is called consumer equilibrium.

Question 27.
Complete the following flow chart:

Answer:

Answer any 2 questions from 31 to 33. Each carries 8 scores.

Question 28.
Explain the short run equilibrium conditions for profit maximization of firms under perfect competitive mar-ket with the help of diagram.
Answer:
Perfect competition is a market situation where large number of buyers and sellers dealing with homogenous product.
Features of perfect competition:

1. Large number of buyers and sellers
2. Homogenous product
3. Perfect information,
4. Uniform price
5. Freedom of entry and exit

Profit maximisation condition of a firm in short run under Derfect corn Detition.
Three Conditions
1. P= Mc
2. MC should cut MR from below
3. Price should be greater than or equal to AVC Here the above mentioned three conditions follows
le. (1)P = MC
(2) MC cuts MR from below
(3) p ≥ AVC

Question 29.
(a) What do you mean by the price elasticity of demand?
(b) The price of potato falls from Rs. 100 to Rs. 75. As a result of which demand rises from 10 kg to 15 kg. Calculate the price elasticity of demand.
(c) Based on the above information, comment on the nature of the elasticity of demand.
Answer:
Deg ree of responsiveness of quantity demanded of a commodity towards the changes in its price is technically known as price elasticity of demand.
ed = \(\frac{\Delta \mathrm{Q}}{\Delta \mathrm{P}} \cdot \frac{\mathrm{P}}{\mathrm{Q}}\)
a) ∆Q = Change in quantity demanded
∆P = Change in price
p = Original Price (Early Price)
Q = Original quantitydemanded (Early demand)

Here
∆Q = 5 (le. 15-10)
∆P = 25 (le. 100-75)
P = 100
Q = 10
Put the above values in to the equation
ie.ed = \(\frac{\Delta Q}{\Delta P} \cdot \frac{P}{Q}=\frac{5}{25} \cdot \frac{100}{10}\) = 2
ed = 2
b) Based on the answer obtained we can say that elasticity of demand is highly positive and elastic.

Question 30.
(a) Differentiate between Marignal Propensity to Consume (MPC) and Marginal Propensity to Save (MPS)
(b) In a two sector economy, Marginal Propensity to Consume (MPC) is 0.6. Find the investment mul-tiplier.
Answer:
a) Marginal propensity to consume is a concept that explains the impact of change in income on consumption.
MPC = \(\frac{change in consumption }{\mathrm{change in income}}\)
= \(\frac{\Delta C}{\Delta Y}\)
Marginal propensity to save explains the impact of change in income on savings
MPS = \(\frac{change in savings }{\mathrm{change in income}}\)
MPS = \(\frac{\Delta S}{\Delta Y}\)

b) Investment Multiplier = \(\frac{1}{\text { MPS }}\)
As know MPS + MPC = 1
so MPS =1- MPC
MPS = 1- 0.6
= 0.4
Investment multiple = \(\frac{1}{\mathrm{MPS}}=\frac{1}{0.4}\) = 2.5

Answer any 2 questions from 31 to 33. Each carries 8 scores. (2 × 8 = 16)

Question 31.
Explain the three methods of measuring GDP.
Answer:
Money value of all final goods and services produced in a nation during a financial year is known as GDP. Calculation of GDP is an important activity in any economy. GDP Can be calculated in 3 different ways, they are:

1. Product method or value added method
2. Income method
3. Expenditure method

Product Method:
Here the GDP is calculated through adding the val-ues of all final goods and services produced by a nation during a financial year. This method is other-wise known as value added method.

Income Method:
Under this method GDP is calculated through the summation of all factor incomes earned during a financial year. Factor incomes means rent, wage, interest and profit

Expenditure Method:
Here the GDP is calculated through adding all types of expenditure madefy the nation during a financial year, expenditures made by public and private are included here.

Question 32.
Describe the monetary policy instruments of RBI.
Answer:
The Policy implemented by central bank to stabilize the economy through controlling supply of money is known as monetary policy. In india the above mentioned duty is performed by RBI. RBI controls supply of money through two methods they are:
1. Quantitative credit control methods
2. Qualitative credit control methods

• Quantitative credit control methods
  1. Bank rate
  2. Open market operations
  3. Change in cash reserves ratios
  4. Repo Rate and Reverse repo rate
  5. Statutory liquidity ratio.
• Qualitative credit control methods
  1. Marginal requirements
  2. Regulation of consumer credit
  3. Credit rationing
  4. Moral suasion
  5. Direct action.
• Explain the following method
  1. Bank rate
  2. Reserve ratios,
  3. Open market operations

Question 33.
(a) Calculate Total Variable Cost (WC), Average Cost (AC), Average Fixed Cost (A FC), Average Vari able Cost (AVC) and Short run Marginal Cost (SMC):

Output	TFC	TVC	FC	AC	AFC	AVC	SMC
0	70		70
1	70		100
3	70		115
4	70		125
5	70		145
6	70		180
7	70		250

(b) Draw Total Cost (TC), Total Fixed Cost (TFC) and Total Variable Cost (TVC) in a single diagram by using the above data.
Answer:

Reviewing Kerala Syllabus Plus Two Physics Previous Year Question Papers and Answers Pdf SAY 2019 helps in understanding answer patterns.

Kerala Plus Two Physics Previous Year Question Paper SAY 2019

Time : 2 Hours
Total Score: 60

Use the following constants wherever neces-sary:

Permitivity of free space, s0= 8.854 × 10^-12 C²N^-1m^-2
Permeability of free space, JI0= 4π0 × 10^-7 Tm/A
Speed of light in vacuum, c = 3 × 10⁸ m/s

Questions 1 to 4 carry 1 score each. Answer any 3 questions. (3 × 1 = 3)

Question 1.
The value pf Electric field inside a charged conductor is ………….
Answer:
Zero

Question 2.
An e.m.f. of 16V is induced in a coil of self-inductance 4H. The rate of change of current must be
(i) 64 A/s
(ii) 32 A/s
(iii) 16 A/s
(iv) 4A/s
Answer:
(iv) 4A/s

ε = \(\frac{\mathrm{L dI}}{\mathrm{dt}}\)
\(\frac{\mathrm{dI}}{\mathrm{dt}}\) = \(\frac{\varepsilon}{L}\) = \(\frac{16}{4}\) = 4 A/s

Question 3.
The fundamental logic gate represented by the following circuit is:

Answer:
NOT

Question 4.
The type of modulation technique using frequency range 88 MHz. to 108 MHz.
Answer:
FM (Frequency modulation)

Questions 5 to 11 carry 2 score each. Answer any 6 questions. (6 × 2 = 12)

Question 5.
(a) The figure shows the Q(charge) versus V (potential) graph for a two combination of capacitors. Identify the graph representing the parallel combination.

Answer:
Graph A

(b) W rite the expression for the effective capacitance of two capacitors connected in parallel.
Answer:
C = C₁ + C₂

Question 6.
An α particle and a proton are moving in a region normal to a uniform magnetic field B. If two particles have equal linear momenta, what will be the ratio of the radii of their trajectories in the field? (2)
Answer:
Linear moment of α and proton are same
P_α = P_P
Radius R = \(\frac{m v}{q B}\)
r ∝ \(\frac{1}{q}\)
qα = 2q
q_P = q
r_α = \(\frac{1}{2 q}\)
r_P = \(\frac{1}{q}\)

Question 7.
The phasor diagram of an a.c. circuit is shown in figure.

(a) Identify the circuit. (1)
Answer:
Answer:
AC circuit containg inductor only

(b) Prove that the average power dissipated in the above circuit is zero. (1)
Answer:
P_av = V_rmsI_rms cosϕ
for pure indutor = ϕ = 90°
P_av = V_rmsI_rms cos90°
P_av = 0

Question 8.
In an electromagnetic wave, the oscillating electric field having a frequency of 3 x 10¹⁰ Hz. and an am-plitude of 30 V/m propagates in free space in the positive x-direction. Write down the expression to represent the electric field. (2)
Answer:
Wave lenght λ = \(\frac{C}{v}\) = \(\frac{3 \times 10^8}{3 \times 10^{10}}\) = \(10^{-2}\)
K = \(\frac{2 \pi}{\lambda}\) = \(\frac{2 \times 3.15}{10^{-2}}\) = 628 rad/m

Angular frequency ω = 2 π v
= 2 × 3.14 × 3 × 10⁸
18.84 × 10 rad/s

Question 9.
An unpolarized beam of light is incidewnt on water surface as in figure.

(a) Name the law relating refractive index of water with angle of incidence. (1)
Answer:
Brewsters law

(b) Find the value of refractive index of water, if the angle of incidence & 53°.
Answer:
n = tan θ
n = tan 53°
n = 1.33

Question 10.
(a) ypte Einstein’s photo electric equation. (1)
Answer:
Einstein’s photo electric equation

(b) Draw a graph showing the variation of Stopping potential with frequency of incident radiation. Mark threshold frequency on the graph.
Answer:

Question 11.
The block diagram of AM transmitter is shown in figure.

(a) Identify X and Y.
Answer:
x – amplitude modulator
y – power amplifier

(b) The amplitudes of modulating signal and carrier wave are 9V and 12V respectively. Find the value of modulation index.
Answer:
Modulation index M = \(\frac{A_M}{A_C}\) = \(\frac{9}{12}\) = 0.75

Questions 12 to 18 carry 3 scores each. Answer any 6 questions. (6 × 3 = 18)

Question 12.
(a) Name the theorem used to find the electric flux through a surface enclosing charge, (1)
Answer:
Guess theorem

(b) Using this theorem derive an expression for the electric field due to an infinite plane sheet of charge with surface charge density o. (2)
Answer:

Consideran infinite thin plane sheet of charge of density σ.
To find electric f ield at a point P (at a distance ‘r’ from sheet), imagine a Gaussian surface in the form of cyiinder having area of cross section ‘ds’.
According to Gauss’s law we can write,
\(\int \overrightarrow{\mathrm{E}} \cdot \mathrm{~d} \overrightarrow{\mathrm{~s}}=\frac{1}{\varepsilon_0} \mathrm{q}\)
\(\mathrm{E} \int \mathrm{ds}=\frac{\sigma \mathrm{ds}}{\varepsilon_0}\) (Since q = σ ds)
But electric field passes only through end surfaces ,so we get
\(\int \mathrm{ds}\) = 2ds
ie. E 2ds = \(\frac{\sigma \mathrm{ds}}{\varepsilon_0}\)
E = \(\frac{\sigma \mathrm{ds}}{2 ds \varepsilon_0}\), E = \(\frac{\sigma }{2 \varepsilon_0}\)
E is directed away from the charged sheet, if a is positive and directed towards the sheet if a is negative.

Question 13.
(a)With suitable circuit diagram. show how emfs of two cells can be compared using a potentiometer. (2)
Answer:

Principle : Potential difference between two points of a current carrying conductor (having uniform thickness) is directly proportional to the length’of the wire between two points.

Circuit details: A battery (B₁), Rheostat and key are connected in between A and B. This circuit is called primary circuit. Positive end of E₁ and E₂ are connected to A and other ends are connected to a-two way key. Jockey is connected to a two key through galvanometer. This circuit is called secondary circuit.

(b) Why do we prefer potentiometer to measure the e.m.f. a cell than a voltmeter? (1)
Answer:
Potentio meter does not take current at null point and hence measure actual emf. Hence potentio meter is more accurate than volt meter.

Question 14.
Based on the magnetic property, materials are classified into diamagnetic, paramagnetic and ferromagnetic.

(a) Compare paramagnetic and ferromagnetic materials in view of magnetic susceptibility. (1)
Answer:
For paramagnetic susceptibility is small and positive but for ferromagnetic its value is positive and high.

(b) State the law expalining the variation of magnetic susceptibility with temperature in the case of ferromagnetic material. What happens to its magnetic property when the temperature is increased? (2)
Answer:
(i) Curie law
(ii) When temparature increases, at a particular temparature ferromagnetic becomes

Question 15.
Motion of a conductor in a magnetic field induces’ an emf across its ends.

(a) Write an expression for the emf induced across the ends of a conductor moving right angles to a uniform magnetic field.
Answer:
ε = Bl v

(b) An aeroplane is flying horizontally from west to east with a velocity of 720 km/h. Calculate the e.m.f. induced between the ends of its wings having a span of 25m. The vertical component of earth’s magnetic field at the place is 2.19 × 10 5T.
Answer:
Velocity = 720 × \(\frac{5}{18}\) = 200 m/s
emf ε = Bl v
= 2.19 × 10^-5 × 200
0.1090 v

Question 16.
The figure below shows the transmission of light signals through an optical fibre.
(Refractive index of the core – n₁, Refractive index of cladding-n₂)

(a) Name the optical phenomenon happening at the point A. (1)
Answer:
Total internal reflection

(b) Write the necessary conditions for this to happen. (1)
Answer:
i) Light should travel from denser to rarer medium,
ii) incident angle must

(c) Write the relationship between critical angle and refractive indices of the material of the core and cladding of the optical fibre. (1)
Answer:
\(\frac{n_2}{n_1}\) = \(\frac{1}{sin c}\)

Question 17.
(a) Draw a graph showing the variation of de-Broglie’s wavelength (A) with accelerating potential (V).(1)
Answer:
Out of syllabus
λ = \(\frac{1}{\sqrt{2 \mathrm{mev}}}\)
λ ∝ \(\frac{1}{\sqrt{r}}\)
This equation is in the form of y ∝ \(\frac{1}{\sqrt{x}}\) hence, we get a graph as shown below

(b) Express de-Broglie’s wavelength in terms of ac-celerating voltage. (2)
Answer:
de-Broglie’s wavelength λ = \(\frac{h}{P}\)
biet P = \(\sqrt{2 \mathrm{mev}}\)
λ = \(\frac{\mathrm{h}}{\sqrt{2 \mathrm{mev}}}\)

Question 18.
The energy of an electron in the nth electronic orbit of hydrogen atom is
E_n = \(\frac{-m e^4}{8 \epsilon_0^2 n^2 h^2}\)
(a) What does the negative sign signify? (1)
Answer:
Negative sigyis shows that electrons are bound to the nucleus.

(b) Obtain the Rydberg formula for the spectral series of hydrogen atom. (2).
Answer:
Energy of hydrogen atom, when elctron is in the ground state
E_i = \(\frac{-\mathrm{me}^4}{8 \varepsilon_0^2 \mathrm{n}_2^2 \mathrm{~h}^2}\)
Energy of hydrogon atom, when electron is in excited state.
E_f = \(\frac{-m e^4}{8 \varepsilon_0^2 n_f^2 h^2}\)

Energy emitted, when an electron comes from 1 excited state into ground state.
∆ E = E_f – E_i

Questions 19 to 22 carry 4 scores each. Answer any 3questions. (3x 4 = 12)

Question 19.
An electric dipole is placed in a uniform electric field of intensity ‘E’. Let ‘0’ be the angle between dipole moment and electric field.

(a) Derive an expression for the torque acting on the electric dipole in vector form. (2)
Answer:
Torque \(\overrightarrow{\mathrm{\tau}}=\overrightarrow{\mathrm{P}} \times \overrightarrow{\mathrm{E}}\)

(b) What orientation of the dipole corresponds to stable and unstable equillibrium. (1)
Answer:
for stable equilibrium, θ = 0°
for unstable equilibrium, θ = 180°

(c) Write the equation of potential energy corre-sponds to stable equilibrium.
Answer:
Ptential energy U = – PE cos Q or U = \(\overrightarrow{\mathrm{P}} . \overrightarrow{\mathrm{E}}\)

Question 20.
An alternating voltage is applied across an LCR cir¬cuit as in figure.
(L = 100mH. C = 10OuF, R = 50Q)

(a) Draw the phasor diagram of the circuit. (1)
Answer:

(b) In the.circuit, if V = 20sin (100t) volts
(i) Impedance
(ii) Peak value of current
(iii) Resonant frequency of the circuits
Answer:

Question 21.
Coherent sources are necessary for producing sus-tained interference.

(a) Write the condition of coherence.
Answer:
Two light sources are said to be coherant, if they emit light waves of same frequency, same amplitude and same phase.

(b) With the help of a suitable diagram, find the dis-tance between two consecutive bright brands pro-duced by Young’s double slit.
Answer:
Young’s double slit experiment

The experiment consists of a slit ‘S’. A monochromatic light illuminates this slit. S₁ and S₂ are two slits in front of the slit ‘S’. A screen is placed at a suitable distance from S₁ and S₂.
Light from S₁ and S₂ falls bn the screen. On the screen interference bands can be seen.

Explanation : If crests (or troughs) from S₁ and S₂. meet at certain points on the screen, the interference of these points will be constructive and we get bright bands on the screen.

At certain points on the screen, crest and trough meet together. Destructive interference takes place at those points. So we get dark bands

Expression for band width

S₁ and S₂ are two coherent sources having wave length λ. Let ‘d’ be the distance between two coherent sources. A screen is placed at a distance D from sources. ‘O’ is a point on the screen equidistant from S₁ and S₂.
Hence the path difference, S₁ O – S₂ O = 0
So at ‘O’ maximum brightness is obtained.
Let ‘P’ be the position of n,h bright band at a distance xn from O. Draw S₁ A and S₂ B as shown in figure.
From the right angle AS₁AP
we get, S₁P² = S₁A² + AP²
S₁P² = D² + (X_n – d/2)²
= D² + X_n² + X_nd + \(\frac{d^2}{2}\)

Question 22.
(a) What do you mean by half life period of a radio-active substance. (1)
Answer:
Half life is the time taken to reduce half of its initial value.

(b) Write the relation between mean life and half life. (1)
Answer:
T_mean = \(\frac{T_{1 / 2}}{0.693}\)

Teachers recommend solving Kerala Syllabus Plus Two Zoology Previous Year Question Papers and Answers Pdf Model 2021 to improve time management during exams.

Kerala Plus Two Zoology Board Model Paper 2021 with Answers

I. Answer the following questions from 1 to 31 upto a maximum score of 30.
Questions 1 to 7 carry 1 score each.

Question 1.
The cells present in the seminiferous tubules of testes that provide nutrients to the male germ cells are called ______.
Answer:
Sertoli cells

Question 2.
Voluntary termination of pregnancy before full term is called ______.
Answer:
Medical termination of pregnanacy (MTP)

Question 3.
Certain standard symbols are used in the pedigree analysis. Draw the symbols of
a) Normal male
b) Affected female
Answer:

Question 4.
Name the process ‘A’ and ‘B’

Answer:
A – DNA Replication
B – Translation

Question 5.
In Miller’s Experiment, the gases used were
a) CH₄, NH₂, H₂O, H₂
b) CH₄, NH₂, CO₂, H₂
c) CH₄, NH₂, O₂, C0
d) CH₄, NH₂, N₂, O₂
Answer:
a) CH₄, NH₂, H₂O, H₂

Question 6.
The large holes in Swiss cheese are due to the production of a large amount of CO₂, by a bacterium named ______.
a) Saccharomyces cerevisiae
b) Propionibacterium sharmanii
c) Trichodermapolysporum
d) Clostridium butylicum
Answer:
Propionibacterium sharmanii

Question 7.
Expand the following :
a) IARI
b) KVIC
Answer:
IARI- Indian Agricultural Research Institute KVIC- Khadi and Village Industries Commission

Questions 8 to 26 carry 2 scores each.

Question 8.
Complete the flow chart.

Answer:
(a)’Mammary alveoli
(b) Mammary tubule

Question 9.
Differentiate ZZ-ZW mechanism of sex determination from XX-XO mechanism.
Answer:

• ZZ – ZW type
  1. Female birds have one Z and one W chromosome, where as males have a pair of Z- chromosomes besides the autosomes.
  2. In birds the total number of chromosome is same in both males and females.
  3. Female heterogamety.
• In XO type and XY type
  1. Males produce two different types of gametes, Such types of sex determination mechanism is seen in drosophila and human male respectively.
  2. Male heterogamety.

Question 10.

a) Identify the process
b) Write the role of UTR in this process.
Answer:
(a) Translation or Protein synthesis
(b) The UTRs are present at both 5’-end and at 3’end are required for efficient translation process

Question 11.
Write any four common warning signs of drug and alcohol abuse in youth.
Answer:

1. Drop in academic performance
2. unexplained absence from school or college
3. lack of interest ¡n personal hygiene
4. deteriorating relationships with family and friends

Question 12.
a) Name the bacteria which converts milk to curd.
b) “It is essential to add a small of curd the fresh milk to get quality curd.”
Answer:
(a) Lactobacillus
(b) A small amount of curd added to the fresh milk act as an inoculum contain millions of LAB, which
at suitable temperatures multiply and convert milk to curd. It also improves the nutritional quality by increasing vitamin B₁₂

Question 13.
Observe the figure
a) Name the part labelled as ‘A’.
b) Write the functions of’A’.

Answer:
(a) Acrosome
(b) It help the sperm to enter into the cytoplasm of egg results fertilization.

Question 14.
List out FOUR ‘Evil Quartet’ which adversely affect the biodiversity.
Answer:

1. Habitat loss and fragmentation
2. Over – exploitation
3. Alien species invasions
4. Co extinctions

Question 15.
“Doctors recommended breastfeeding is inevitable in initial period of infant growth.” Do you agree with this statement? Justify your answer.
Answer:
The milk produced during the initial few days of lactation is called colostrum which contains several antibodies provide resistance for the new-born babies.

Question 16.

i.‘S’ Strain	Inject into Mice
ii. ‘R’ Strain	Mice die
iii. ‘S’ Strain (Heat Killed)	Mice live
iv. ‘S’ Strain (Heat Killed) + ‘R’ Strain (Live)	Mice live

a) Identify the experiment.
b) Why did the mice die when a mixture to heat killed ‘S’ strain and live ‘R’ strain was injected?
Answer:
(a) Griffith experiment
(b) In a mixture of heat-killed S and live R bacteria, the mice died and recovered living S bacteria from the dead mice. It is due to transforming principle transferred from the heat-killed S strain, to the R strain to synthesise a smooth polysaccharide coat and become virulent.

Question 17.
Father has ‘A’ group Mother has ‘O’ group blood. Find out the possible blood groups of their children.
Answer:
The Possible blood groups of children’s ‘A’ or O group

Question 18.

a) Identify the figure
b) What is its significance in birth control?
Answer:
(a) Tubectomy in female
(b) It is the permanent method of birth control

Question 19.
Differentiate narrowly utilitarian arguments and broadly utilitarian arguments. Give one example for each.
Answer:

Narrowly utilitarian	Broadly utilitarian
Humans get economic benefits from nature.	Biodiversity plays a major role in ecosystem services.
Eg. food, firewood, fibre, construction material, industrial products and products of medicinal importance.	Eg. Amazon forest is through photosynthesis produce 20 per cent of the total oxygen in the earth’s atmosphere.

Question 20.

a) Name the genetic disorder illustrated in this figure.
b) Redraw the amino acid sequence with normal haemoglobin.
Answer:
(a ) Sickle – cell anaemia

Question 21.
Complete the illustration showing the features of an ideal contraceptive.

Answer:
(a) User friendly
(b) Easily available
(C) Effective
(d) Reversible

Question 22.

a) Identify the figure
b) Name the part labelled as ‘P’ and write about its significance.
Answer:
(a) Blastocyst
(b) Inner cell mass – It gets differentiated into embryo.

Question 23.
Categories the following diseases under two headings
(Chlamydiasis, HIV infection, Hepatitis-B, Trichomoniasis)

Completely Curable	Non Curable

Answer:

Completely Curable	Non Curable
Chlamydiasis, Trichomoniasis	HIV infection, Hepatitis – B

Question 24.
a) Expand the term AIDS.
b) Name the causative organism.
c) Identify the diagnostic technique to detect AIDS.
d) Write any two preventive methods to avoid AIDS.
Answer:
(a) Acquired mm uno Deficiency Syndrome

(b) Human 1mm une deficiency Virus or HIV

(c) ELISA Test Enzyme Linked 1mm uno – Sorbent Assay

(d) 1. Use disposable syringe and needles.
2. Propr monitoring of blood before blood transfusion.
3. Avoid intercourse with unknown partner.

Question 25.
Fill in the blanks using the terms given below.
Answer:
(a) Opioids
(b) Papayer somniferum
(c) Hashish
(d) Cannabis sativa

Question 26.
Diagrammatic representation of the operation of Natural selection on different traits are given below.

a) Identify the figures which show stabilising and disruptive selection.
b) What is founder effect?
Answer:
(a) Figure A – Stabilising selection
Figure C – Disruptive selection

(b) The change in allele frequency in the small population from a large population leads to the evolution of new species The original drifted population becomes founders and the effect is called founder effect.

Questions 27 to 31 carries 3 scores each.

Question 27.

a) Identify the process
b) Name the parts labelled as ’A’ and ’B’.
c) Distinguish template strand and coding strand.
Answer:
(a) Transcriptional unit

(b) A – Promoter
B – Terminator

(c) Template strand – with 3-5 polarity, mRNA is produced from template strand. Coding strand Strand- with 5 ‘ 3 polarity , It does not code for anything strand.

Question 28.
a) Mention the different steps involved in test tube baby programme.
b) DifferentiateAl and IUI.
c) Write any two reasons for infertility.
Answer:
(a) In test tube baby programme, ova from the wife and sperms from the husband are collected and are induced to form zygote under simulated conditions in the laboratory.

The zygote with upto 8 blastomeres is transferred into the fallopian tube (ZIFT – zygote intra fallopian transfer) and embryos with more than 8 blastomeres, into the uterus (lUT – intra uterine transfer), to complete its further development.

(b)

AI (Artificial insemination)	lul Intra (Uterine insemination)
Semen collected from the donor isartificially into the vagina.	Semen collected from the donor is artificially into the uterus.

(c) 1. Physical or congenital problems
2. Immunological reason

Question 29.
a) Name the three layers of uterus.
b) Identify the layer which exhibits strong contractions during pregnancy.
c) Name the glandular layer that undergoes cyclical changes during menstrual cycle.
Answer:
(a) Perimetrium, Myometrium, Endometrium
(b) Myometrium
(c) Endometrium

Question 30.
a) Name the genetic disorder caused due to the presence of an additional copy of ‘X’ chromosome.
b) Write down Karyotype and mention at least two characters of that syndrome.
Answer:
(a) Klinefelter’s syndrome

(b) 44A + XXY.

• Masculine development
• Gynaecomastia

Question 31.

a) Identify the figure.
b) Distinguish Homologous and Analogous organs.
c) Comment on the evolutionary significance.
Answer:
(a) Homologous Organ

(b)

Homologous Organ	Analogous organ
Same structure with different function	Similar function but differ in structure
Represent divergent evolution	Represent convergent evolution

(c) Homologous organ represent divergent evolution. Analogous organ represent convergent evolution.

Teachers recommend solving Kerala Syllabus Plus Two Zoology Previous Year Question Papers and Answers Pdf Model 2022 to improve time management during exams.

Kerala Plus Two Zoology Board Model Paper 2022 with Answers

Part – I

A. Answer any three questions from 1 to 4. Each carries 1 score.

Question 1.
Mention any one of the factors that affects Hardy Weinberg equilibrium.
Answer:
Gene migration

Question 2.
Embryo with 8-16 Blastomeres is called
Answer:
Morula

Question 3.
Expand SNPs
Answer:
Single nucleotide polymorphism

Question 4.
State the term indicating the ceasing of menstrual cycle.
Answer:
Menopause

B. Answer all questions from 5 to 6. Each carries 1 score. (2 × 1 = 2)

Question 5.
The World Summit on Systainable Development was held in 2002 in _______ South Africa.
Answer:
Johannesburg

Question 6.
The first antibiotic discovered was
Answer:
Penicillin

Part-II

A. Answer any two questions from 7 to 9. Each carries 2 scores. (2 × 2 = 4)

Question 7.
Write any four characteristic features of individual inflicted with Down’s syndrome.
Answer:

1. Short statured
2. Small round head,
3. Furrowed tongue,
4. Partially open mouth

Question 8.
Fungi forms symbiotic associations with plants. What advantages the plant derives from this association?
Answer:

1. This associations helps to absorbs phosphorus from soil:
2. Resistance to root-borne pathogens,
3. Tolerance to salinity and drought,
4. Overall increase in plant growth and development

Question 9.
Complete the table with appropriate terms.

Name of Disease	Causative Organism	Type of Pathogen
Typhoid	A	Bacteria
B	Plasmodium	Protozoa
Ringworm	Microsporum	C
Ascariasis	D	Helminth

Answer:
A – Salmonella typhi
B – Malaria
C – Fungi
D – Ascaris

Answer any two questions from 10 to 13. Each carries 2 scores. (2 × 2 = 4)

Question 10.
Differentiate active immunity and passive immunity.
Answer:

Active Immunity	Passive Immunity
When a host is exposed to antigens, which may be in the form of living or dead microbes or other proteins, antibodies are produced in the host body Active immunity is slow and takes time to give its full effective response.	When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity Passive immunity is quick and takes short time to give its full effective response.

Question 11.
(a) Name the theory of origin of life proposed by Oparin and Haldane.
(b) Who experimentally proved theory?
Answer:
a) Chemical evolution
b) S.L. Miller

Question 12.
Complete the pathway of milk secreted from the alveoli of mammary glands.

Answer:
a) Mammarytubule
b) Mammary duct

Question 13.
Describe test cross and mention its significance.
Answer:
a) Itis the crossing of a Fi progenywith its recessive parent.
b) It is used to find unknown genotype of an individual

Part – III

A. Answer any three questions from 14 to 17. Each carries 3 scors. (3 × 3 = 9)

Question 14.
‘Prevention is better than cure’. What are the measures useful for prevention and control of alcohol and drugs abuse among adolescents? (any three measures)
Answer:

1. Avoid undue peer pressure
2. Education and counselling
3. Seeking help from parents and peers.

Question 15.
Pedigree study provides a strong tool in human ‘ genetics to trace the inheritance of a specific trait.
Define Pedigree analysis and identify the following symbols used in Pedigree analysis:

Answer:
Pedigree analysis Analysis of trait in a several generations of a family is called pedigree analysis.

1. Mating between relatives (consanguineous mating)
2. Sex unspecified
3. Female
4. Mating

Question 16.
The graph showing species area relationship is given.

(b) How is species richness related to area?
(c) What is the range of ‘Z’ value?
Answer:
a)  Z = slope of the line (regression coefficient)
C = Y – intercept

b) Within a region species richness increased with increasing explored area, but only up to a limit

c) 0.1 to 0.2

Question 17.
Distinguish homologous organs and analogous organs with one example for each and mention the type of evolution that led to the formation of homologous and analogous organs.
Answer:

Homologous organs	Analogous organs
Homologus organs are organs having same structure and origin but different functions.	Analogous Organs having same function but different structure and origin
Eg: whales, bats,Cheetah and human share similarities in the pattern of bones of forelimbs	Eg: Wings of butterfly and of birds
Homologus organs are developed due to divergent evolution.	Analogous are deve-loped due to Con-vergent evolution

B. Answer the following questions. Carries 3 scores. (1 × 3 = 3)

Question 18.
In Eukaryotes the heterogenous nuclear RNA (hnRNA) is a precursor of mRNA’. Explain the steps involved in the processing of hnRNA.
Answer:
The Heterogenous nuclear RNA (HnRNA) contain both the exons and the introns and are non-functional.
Hence, it is subjected to a processing.

Splicing : Here the introns are removed and exons are joined

Capping : In capping an unusual nucleotide (rnethyi guanosine triphosphate) is added to the 5’-end of
hnRNA..

Tailing : In tailing, adenylate residues (200-300) are added at 3’-end of a template strand

Part – IV

Answer any one question from 19 to 20. Carries 5 scores. (1 × 5 = 5)

Question 19.
(a) What is the central dogma in molecular biology and name any two processes involved in it?
(b) “In Eukaryotes, gene expression can be regulated at several levels.” Which are they?
Answer:
(a) Central Dogma in molecular biology is the unidirectional flow of information from DNA-RNA- Protein Processes in central Dogma in molecular biology

1. DNA Transcription
2. DNA Translation

(b) Regulation of gene expression in Eukaryotes

1. Transcriptional level (formation of primary transcript),
2. Translational level

Question 20.
Diagrammatic sectional view of the female reproducitve system is given below.
(a) Identify the parts labelled as A, B, C and D.
(b) Mention the surgical contraceptive methods in male and female and name the part which is cut or tied up in each method.

(a) Identify the parts labelled as A, B, C and D.
(b) Mention the surgical contraceptive methods in male and female and name the part which is cut or tied up in each method.
Answer:
(a) A – Ampulla
B – Ovary
C – Fimbriae
D – Cervical canal

b) Surgical contraceptive method in male : Vasectomy
The part which is cut or tied up in Vasectomy : Vas deferens
Surgical contraceptive method in male : Tubectomy.
The pat which is cut or tied up in Tubectomy : fallopian tube.

Teachers recommend solving Kerala Syllabus Plus Two Zoology Previous Year Question Papers and Answers Pdf Model 2023 to improve time management during exams.

Kerala Plus Two Zoology Board Model Paper 2023 with Answers

I. Answer any 3 q uestions from 1 -5. Each carries 1 score. (3 × 1 = 3)

Question 1.
Write the part of fallopian tube where fertilization takes place in human beings.
Answer:
Aampullary-isthmic junction

Question 2.
Select the completely curable sexually transmitted infections (STIs) from the following:

Genital herpes SPphilis Chiamydiosis Hepatities-B

Answer:
Syphilis, Chlamydiasis

Question 3.
obserye the given figure showing global magnitude of biodiversity in vertebrates. Identify the group of animals labelled as A.

Answer:
Fishes

Question 4.
Expand:
(a)UTR
(b)VNTR
Answer:
(a) Untranslated Regions
(b) Variable Number of Tandem Repeats

Question 5.
Identify the first word pair relationship and fill theblank with suitable word for second pair.
Answer:
Brain

II. Answer any 9 questions from 6-16. Each carries 2 scores.

Question 6.
(a) Define placenta.
(b) Write any 2 hormones secreted from placenta.
Answer:
(a) Structural and functional connection between embryo and maternal body is called placenta I Chorionic villi and uterine tissues together form the placenta.

(b)
1. Human chorionic gonadotropin
2. Human placental lactogen

Question 7.
Biodiversity loss is dangerous threat facing planet earth in present days. Write the four reasons of Biodiversity loss given as evil quartet.
Answer:

1. Habitat loss and fragmentation
2. Over-exploitation
3. Alien species invasions
4. Co-extinctions

Question 8.
(a) Define homologous organs.
(b) Analogous structures are a result of the evolution.
Answer:
(a) Organs that has similar structure but having different function.
(b) Convergent evolution.

Question 9.
Name the microbes which produce the following bioactive molecules and write use of (a) and (b).
(a) Cyclosporin A
(b) Statin
Answer:
(a) Trchodenna polysporum.
Used as Immunosuppressive agent.

(b) Monescus purpureus,
Blood diolesterol lowering agents.

Question 10.
Complete the table by filling (A) and (B)

Birth Control Methods
Sterilisation	(B) ________
Vasectomy (A) _______	Multiload 375 Lipper’s Loop

Answer:
(A) – Tuboctomy
(B) – Non-medicated IUDs

Question 11.
Identify the given symbols of Pedegree.

Answer:
(a) MaleorUnaffected male
(b) Female or Unaffected female
(C) Mating
(d) Mating between relatives or consanguineous mating.

Question 12.
Observe the given figure and answer the following questions:

(a) Identify the given strucutre
(b) Name (A) and (B)
Answer:
(a) Nudeosorne
(b) (A)-DNA
(B) Histone octamer

Question 13.
Complete the given representation:

Answer:
(A) Skin
(B) Physiological Barrier
(C) PMNL – neutrophils or Monocytes
(D) Cytokine Barriers.

Question 14.
(a) A man with blood group ‘AB marries a woman with blood group ‘O’. Write the possible genotes of blood grotipsAB and O.
(b) Write the possible genotypes of their offsprings by suing Punnet Square.
Answer:
(a) AB blood group genotpe – \(\|\left.^A\right|^B\)
O blood group genotype – ii

Question 15.

Scientists	Contribution
George Gamow	DNA finger-printing
Alec Jeifreys	Chargaff Rule
Frederick Griffith	Genetic Code
Taylor and Colleagues	Transformation experiment
	DNA replication

Answer:

Scientists	Contribution
George Gamow	Genetic Code
Alec Jeifreys	DNA finger-printing
Frederick Griffith	Transformation experiment
Taylor and Colleagues	DNA replication

Question 16.
Using the given terms in brackets complete the evolutionary stages of man. (homo habilis, Ramapithecus, Homo erectus, Neanderthal man)

Answer:
(A) Ramapithecus
(B) Homo erectus
(C) Neanderthal man
(D) Homo sapiens (Not given in question)

III. Answer any 3 questions from 17 to 20. Each carries 3 scoers. (3 × 3 = 9)

Question 17.
Observe the given figures A and B. Answer the following questions:

(a) Name the embryoñic stages in figure A and B.
(b) In figure B outertayer is trophoblast, and inner group of cells attached to trophoblast is ___
(C) Define implantation.
Answer:
(a) A – Morula
B – Blastocyst
(b) Inner cell mass
(c) Blastocyst embedded in the endometrium of the uterus is called implantation.

Question 18.
Answer the following questions:
(a) Complete the given representation.

(b) Categorie the following bases into Purines and Pyrimidines:
Adenine, Cytosine, Uracil, Guanine
(c) DNA is made up of two polynucleotide chains where back bone is constituted by ______ and bases project inside.
Answer:
(a) (A) – Transcription
(B) Translation
(b) Purines – Adenine and Guanine. Pyrimidines – Uraail & Cytosine.
(c) Sugar – phosphate.

Question 19.
(a) Cancer causing agents are called ____
(b) Differentiate between benign tumour and malignant tumour.
(c) Write any two methods to detect cancer of the internal organs.
Answer:
(a) Carcinogens.

(b) Benign Tumors:
The cancer, which are localized to a particular tissue, are called benign tumor. They cause little damage.

Malignant Tumors:
Mali gnant tumors consist of mass of proliferative cells. The cells can invade to other tissues

(c) (i) Radiography
(ii) MRI (magnetic resonance imaging).

Question 20.
Observe the figures given in (A), (B) and (C) and answer the questions.
(a) Identify and write the genetic disorder in (A), (B) and (C).
(b) Write any three Mendalian disorders.

Answer:
(a) (A) Down’s Syndrome
(B) Klinefelter’s Syndrome
(C) Turner’s Syndrome
(b) Haemophilia, Sickle-cell anaemia, Phenylketonuna,

Teachers recommend solving Kerala Syllabus Plus Two Zoology Previous Year Question Papers and Answers Pdf SAY 2019 to improve time management during exams.

Kerala Plus Two Zoology Question Paper SAY 2019 with Answers

Answer all questions from 1 to 3. Each carries 1 Score. (3 × 1 = 3)

Question 1.
Find out the correct sequence:
a) Fertilisation – Zygote – Blastula – Morula – Cleavage – Implantation
b) Fertilisation – Zygote – Cleavage – Morula – Implantation – Blastula
c) Fertilisation – Zygote – Morula – Cleavage – Implantation – Blastula
d) Fertilisation – Zygote – Cleavage – Morula – Blastula – Implantation
Answer:
Fertilisation-Zygote – cleavage-Morula-blastula Implantation

Question 2.
Identify the following symbols in pedigree Analysis :

Answer:
a) Mating
b) Marriage between relatives

Question 3.
In a double strandard DNA, the ratios between Adenine and Thymine, Guanine and Cytosine are constant and equal one. Who observed this fact?
Answer:
Ervin Chargaff

Answer any 9 questions from 4-14. Each carries 2 Scores.

Question 4.
Observe the cross of a pure violet and white flower.

a) By using the F₁ progeny design a test cross.
b) Mention the significance of test cross.
Answer:

b) It helps to find out the unknown genotype of organism

Question 5.
‘Don’t die of ignorance.
a) About which it is mentioned?
b) List two measures taken by WHO to prevent it.
Answer:
a) HIV infection

b) 1. blood transfusion must be safe
2. use dispossible syringes and needles in public and private Hospitals

Question 6.
Match the following:

A	B
a) Citric Acid	i) Acetobactor aceti
b) Acetic Acid	ii) Clostridium butylicum
c) Lactic acid	iii) Aspergillus niger
d) Butyric Acid	iv) Lacto bacillus
	v) Trycoderma polysporum
	vi) Saccharomyces cervisiae

Answer:

A	B
a) Citric Acid	Aspergillus niger
b) Acetic Acid	Acetobacter aceti
c) Lactic acid	Lactobacil lus
d) Butyric Acid	Clostridium butylicum

Question 7.
Each symptom of two chromosomal disorders are given below:
Gynaecomastia Rudimentary ovary and lack of secondary sexual characters.
Answer:
Gynaecomastia- Kilnefelter’s syndrome Rudimentary ovary and lack of secondary sexual characters – Turner’s Syndrome

Question 8.
Observe the diagram of a double stranded DNAstrand:

Identify the bonds A, B, C & D A, B, C, D
Answer:
A – Hydrogen bond
B – phospho esterbond
C – phospho di esterbond
D – Glycosidic bond

Question 9.
‘LH Surge’ induces the rupture of Graafian follicle.
a) Which gland produces LH and in which day LH Surge happens?
b) Write the role of LH in males.
Answer:
a) Pituitary gland, 14th day

b) LH acts at the Leydig cells and stimulates synthesis and secretion of androgens

Question 10.
Bio-fertilisers are organisms that enrich the nutrient quality of the soil. How these biofertilisers enrich the soil nutrients? Give two examples.
Answer:
a) Microbes can fix atmospheric N₂
Eg. Azospirillum and Azotobacter

Question 11.
Based on evolution in the geological period arrange the plants and animals in the correct order in various million years ago. Choose the appropriate organisms from the bracket.
a) 500 m ya :
b) 350 m ya :
c) 320 m ya :
d) 200 m‘ya :
Answer:
a) 500 mya – Invertebrates
b) 35Omya – jawless fish
c) 320m ya – sea weeds
d) 200mya – Reptiles

Question 12.
The following diagram shows a process in the Ribosome:

Identify the process and explain.
Answer:
Translation step of protein synthesis During this process, ribosome moves from codon to codon along the mRNA and the amino acids are joined by peptide bond i.e polymerisation of amino acids to form a polypeptide.

Question 13.
Make a flow chart using the following terms :
[Natural selection, Struggle for existence, Variation, Origin of species, Over production, Survival of the fittest]
Answer:

Question 14.
Observe the figure and answer the following questions:

a) Identify the given molecule.
b) Mention two types of immune respones in human body.
Answer:
a) Antibody or Immunoglobulin
b) Humoral immune response Cell mediated immunity

Answer any 3 Questions from 15 to 18. Each carries 3 scores. (3 × 3 = 9)

Question 15.
Write the effect of the following drugs in human body:
a) Ophiods
b) Cannabinoids
c) Coca alkaloids
Answer:
a) Ophioids – Effect on central nervous system
b) Can nabinoids – Effect on brain or cardiovascular system of body
c) coca alkaloids – It has a stimulating action on central nervous system, producing a sense of euphoria and increased energy

Question 16.
There are several method of in vitro fertilisation to assist couples who lack the ability of fertilisation.
a) Give the popular name of the programme.
b) Suggest two techniques of in vitro fertilisation and their conditions of transfer to assist these people.
Answer:
a) Assisted reproductive technologies

b) ZIFT : zygote intra fallopian transfer: The zygote or early embryos upto 8 blastomeres transferred into the fallopian tube

GIFT : gamete intra fallopian transfer: Transfer of an ovum collected from a donor into the fallopian tube of another female who cannot produce one, but provide suitable environment for fertilisation and further development

Question 17.
In your school the Science Club decided to conduct a seminar about “Biodiversity conservation – Approaches.” You are invited to present a paper on this seminar. List out the main points you include d in the presentation. [Hint: In Situ, Ex-Situ conservation]
Answer:
In situ conservation – Organisms are protected in their natural habitat Eg. sacred groves, biosphere reserves, national parks and sanctuaries. Ex situ conservation – It is the conservation of threatened animals and plants outside their natural habitat. Examples are Zoological parks, botanical gardens and wildlife safari parks.

Question 18.
Transcription of eukaryotes are more complicated than that of prokaryotes. Explain any two additional complexities found in the transcription of eukaryotes.
Answer:
Three types of RNA polymerases in eukaryotes RNA processing Three important steps are involved – Splicing, capping, Tailing

1. In splicing the introns are removed and exons are joined toether.
2. In capping an methyl guanosine triphosphate is added to the 5’-end of hnRNA.
3. In tailing, adenylate residues are added at 3-end in a template.

Teachers recommend solving Kerala Syllabus Plus Two Zoology Previous Year Question Papers and Answers Pdf March 2020 to improve time management during exams.

Kerala Plus Two Zoology Question Paper March 2020 with Answers

I. Answer any 3 questions from 1 – 5. Each carries 1 score. (3 × 1 = 3)

Question 1.
From the following, find out the symbol used in the human pedigree analysis representing male.

Answer:

Question 2.
Name the technique of transferring embryos upto 8 blastomeres into the fallopian tube.
a) GIFT
b) ZIFT
c) ICSI
d) IUI
Answer:
b) ZIFT

Question 3.
Microbe which help in the production of Biogas.
a) Aspergillus nicier
b) Trichoderma Polvsoorum
c) Saccharomyces derevisiae
d) Methanobacterium
Answer:
d) Methanobacterium

Question 4.
Which of the following human ancestor is more ‘ape’ like?
a) Homo habilis
b) Drypithecus
c) Australo pithecines
d) Homo erect us
Answer:
b) Drypithecus

Question 5.
Select the cause of etinction of Cichlid fish in lake Victoria of East Africa.
a) Habitat loss and fragmentation
b) Over-exploitation
c) Alien species invasions
d) Co-extinctions
Answer:
c) Alien species invasions

II. Answer any 9 questions from 6-16. Each carries 2 scores. (9 × 2 = 18)

Question 6.
Some examples of microbes in human welfare are given. Classify them under the heading given below.

Microbes in house hold products	Microbes as biofertil izers

Answer:

Microbes in house hold products	Microbes as biofertil izers
. Pmponibactonum sharmani	. Rhizobium
. Lactic acid bacteria	. Azospinllum
. Sacharomyces cervisiae	. Anabaena
	. Azotobacter
	. Aspergillus niger

Question 7.
Observe the figure given below showing Mendel’s experiment using pea plants.

a) Identify the’crossg!
b) Which are the laws proposed by Mendel based on this observations?
Answer:
a) Monohybrid cross

b) 1. Law of dominance
2. Law of segregaton or Law of purity of gametes

Question 8.
“All copulations lead to fertilization and pregnancy”. Do you agree with this statement? Justify your answer.
Answer:
No.
Fertlisaton can only occur if the ovum and sperms are transported simultaneously to the ampullary isthmic junction.

Question 9.
Fill the blanks in Column A and B using appropriate terms.

Theory	Scientists
a) Theory of natural selection	A
b) Use and disuse of organs	B
c) Theory of mutation	C
d) Theory of spontaneous generation	D

Answer:

Theory	Scientists
a) Theory of natural selection	Charles Darwin
b) Use and disuse of organs	Jean Baptste de
c) Theory of mutation	La marck
d) Theory of spontaneous generation	Hugo deVries

Question 10.
One of the salient features of genetic code is “Universal”.
a) Write any other two salient features of Genetic code.
b) Which is the initiator codon? And name the amino acid it codes.
Answer:
a) 1. The codon is triplet
2. One codon codes for only one amino acid, hence, it is unambiguous and specific

b) AUG-Methionine

Question 11.
Amniocentesis for sex determination is legally banned now.
a) What is amniocentesis?
b) Why it is banned?
Answer:
a) It is the prenatal 1oetal sex determination test based on the chromosomal pattern in the amniotic fluid surrounding the developing embryo

b) It is banned for preventing female foeticides

Question 12.
Name any two protozoan diseases, its causative organism and any two symptoms.
Answer:
Malaria and Amoebiasis
Malaria : Pathogen : Plasmoidum vivax, P. malaria and P. falciparum Symptom: Chill and high fever recurring every three to four days

Amoebiasis: Pathogen: Entamoeba histolytica Symptom: constipation, abdominal pain and cramps

Question 13.
Tropical Amazonian rainforest in South America has the greatest biodiversity on earth. Do you agree with this? Explain.
Answer:
Yes

1. Temperate regions subjected to frequent glaciations in the past but the tropics undisturbed for millions of years, so in tropics evolution leads to species diversification.
2. Tropical environments are less seasonal, constant and predictable. Such constant envronments promote niche specialis.ation and lead to a greater species diversity
3. The availability more solar energy In the tropics causes higher productivity, so it leads to greater diversity.

Question 14.
Complete the illustration chart given below.

Answer:
a) Oploids
b) Central nervous system
C) Papayer somniferum
d) Cannabis sativa

Question 15.
Correct the following statements, if there is any mistake:
a) Haemophilia is an autosome linked recessive disease.
b) Turner’s syndrome is due to the presence of an additional copy of X chromosome.
Answer:
a) Haemophilia is a sex linked recessive disease
b) Turner’s sidrome is due to the absence one of the X chromosome

Question 16.
p² + 2pq + q² = 1 denotes an evolutionary principle.
p² + 2pq + q² = 1 agianto)”
a) Name the principle.
b) Mention any three factors affecting this.
Answer:
a) Hardy—Weinberg prindple

b) i) Gene migratiop
ii) Genetic drift
iii) Mutation

III. Answer any 3 questions from 17 – 20. Each carries 3 scores. (3 × 3 = 9)

Question 17.
Observe the figure given below:

a) Identify the process in the picture.
b) Name any two enzymes needed for this process,
c) Write the peculiarities of the newly synthesized daughter strands.
Answer:
b) Helicase and DNA ligase
c) Among the two newly synthesized strands,One strand is continuously produced and other strand is discontinuously produced.

Question 18.
Explain the measures useful for prevention and control of alcohol and drugs abuse among adolescents.
Answer:

1. Avoid undue peer pressure
2. Education and counseling
3. Seking help from parents and peers

Question 19.
The graph given below shows the level of the ovarian hormones in a normally menstruating woman during the follicular phase.

a) Name ‘A’ and ‘Bi.
b) Reconstruct the graph showing the level of hormones in luteal phase.
c) Name the hormone secreted by Corpus Luteum and mention its function.
Answer:
A – Progesterone

B – Estrogen

(c) Progesterone Function:
It support during pregnancy or it maintain Endometrium of uterus

Question 20.
A DNA sequences is provided below.
a) Write down the sequence of its complementary strand.
b) Name the enzyme involved in transcription of DNA.
c) What would happen if both the strands of the DNA act as templates for transcription?
Answer:
a) 3’-TACG TACG TACG TACG TACG TACG TA-5’

b) DNA dependent RNA polymerase

c) If both strand act as a template the following things will happen

1. Two RNA molecule will be produced with different sequences and results in the formation of 2 different protein.
2. Two RNA molecu’e will be produced, they are complementary to each other, hence ds RNA will not translate into protein.

Reviewing Kerala Syllabus Plus Two Physics Previous Year Question Papers and Answers Pdf March 2024 helps in understanding answer patterns.

Kerala Plus Two Physics Previous Year Question Paper March 2024

Time: 2 Hours
Total Scores : 60

I. Answer any 5 questions from 1 to 7. Each carries 1 score. (5 × 1 = 5)

Question 1.
The SI unit of electric flux
(a) NC^-1
(b) NmC
(c) Nm²C²
(d) Nm²C
Answer:
(c) Nm²C²

Question 2.
The net electric field inside a conductor when placed in an external electric field is
(a) Zero
(b) Half
(c) Two times
(d) Four times
Answer:
(a) Zero

Question 3.
The SI unit of power of lens
(a) N
(b) J
(c) W
(d) D
Answer:
(d) D

Question 4.
‘The locus of points which have the same phase is called a wave front” the statement is True/Faise.
Answer:
True.

Question 5.
The expression for de Broglie wavelength associated with a particle is ………….. .
Answer:
\(\frac{h}{mV}\) = \(\frac{h}{P}\)

Question 6.
Which element in the periodic table shows maximum binding energy per nucleon?
Answer:
Fe⁵⁶ (Iron)

Question 7.
What is an intrinsic semiconductor?
Answer:
A semiconductor in its pure form is called in-trinsic semiconductor.

Answer any 5 questions from 8 to 14. Each carries 2 scores. (5 × 2 = 10)

Question 8.
What is an equipotential surface? Give an example.
Answer:
An equipotential surface is a surface in a region of space where every point on that surface has the same electric potential. In other . words, it’s a surface where the electric potential is constant.
Example: All points equidistant from a point charge.

Question 9.
Define drift velocity, give its equation.
Answer:
Drift velocity is defined as the average velocity acquired by and electron under the applied electric field.
V_d = \(\frac{-eEτ}{m}\)

Question 10.
State Gauss’s law in maghetism.
Answer:
The net magnetic flux through ant closed surface is zero.
ϕ_B = \(\sum_{\text {all }} \mathrm{B} \cdot \Delta \mathrm{~S}=0\)

Question 11.
What is magnetic flux and how is it measured?
Answer:
Magnetic flux is defined as the number of magnetic field lines passing through a given area.
The number of magnetic field lines passing through the surface gives the measure of magnetic flux.
ϕ = \(\sum_{\text {all }} \overrightarrow{\mathrm{B}} . \Delta \overrightarrow{\mathrm{S}}\)

Question 12.
The household line voltage of ac measured is 220 V, calculate its peak voltage.
Answer:
V_m = V_rms × \(\sqrt{2}\)
= 1.414 × 220
= 311 V

Question 13.
What is stopping potential?
Answer:
This is minimum negative potential given to collector plate for which the photo electric current becomes zero.
Stoping potential is denoted as V₀
\(\frac{1}{2}\) mV² max = eV₀

Question 14.
What is nuclear fission? Give one example.
Answer:
Nuclear fusion is the splitting of a heavy nucleus into two lighter nuclei.
Splitting of the uranium-235 nucleus when it is bombarded with neutrons.

Answer any 6 questions from 15 to 21. Each carries 3 scores. (6 × 3=18)

Question 15.
State and explain the force between electric charges.
Answer:

The force of attraction or repulsion between two point charges is directly proportional to the product of the charge and inversely proportional to the square of the distance between them. The force between the charges is given by,
F ∝ q₁q₂
F ∝ \(\frac{1}{r^2}\)
F ∝ \(\frac{q_1 q_2}{r^2}\)
F = \(K \frac{q_1 q_2}{\mathbf{r}^2}\)
when the medium between the charges is air or vacuum.
\(F_{\text {vecuum }}\) = \(\frac{1}{4 \pi \varepsilon_0} \frac{q_1 q_2}{r^2}\)

Question 16.
Figure shows the two current carrying conductors. Derive the expression for force between the conductors.

Answer:

The magnitude of the magnetic induction B-p at the right side conductor Q is,
\(B_{P}\) = \(\frac{\mu_0 i_1}{2 \pi d}\)
The force on a length L of the ‘Q’ conductor is Fg/> = Bpi2L
\(F_{QP}\) = \({B_P i_2 L}\)
= \(\frac{\mu_0 i_1}{2 \pi d} i_2 L\)
= \(\frac{\mu_0 i_1 i_2}{2 \pi d} L\)
Force per unit length can be written as
\(F_{QP}\) = \(\frac{\mu_0 i_1 i_2}{2 \pi d}\)

Question 17.
Compare dia, para and ferromagnetic substances with suitable examples.
Answer:
Diamagnetic substance:

• These substances when placed in a magnetic field, acquire feeble magnetism opposite to the direction of the magnetic field.
• They are feebly repelled by a magnet.
• The relative permeability of these substances are slightly less than 1 .
• The susceptibility has a small and negative value.
• When they are placed in a magnetic field, the magnetic lines of force are repelled. They do not pass through the material.
• Examples: Copper, Silver, Bismuth.
  

Paramagnetic substance:

• These substances when placed in a magnetic field, acquire feeble magnetism in the direction of the magnetic field.
• They are feebly attracted by a magnet.
• The relative permeability of these substances are slightly greater than 1.
• The susceptibility value is small and positive.
• When they are placed in a magnetic field, the magnetic lines offeree pass through them.
• Examples: Aluminium, Sodium, Calcium, Oxygen (at STP)
  

Ferromagnetic substance :

• These substances when placed in a magnetic field are strongly magnetised in the direction of the magnetic field.
• They are strongly attracted by a magnet.
• The relative permeability of these substances is very high.
• The susceptibility is large and positive.
• When they are placed in a magnetic field, most of the magnetic lines of force pass through them.
• Examples : Iron, Nickel, Cobalt, natural magnet.

Question 18.
What is self-induction and define the expression for self-inductance of a solenoid.
Answer:
When current in a coil changes the magnetic flux linked with the coil also changes and a back emf is induced in the coil. This phenomenon is known as self induction.
The magnetic flux through one turn of the solenoid is given by,
ϕ = BA = (μ₀nI)A
The magnetic flux linkage in the solenoid with a total number of n/turns is given by,
ϕ = μ₀n²AIl
But ϕ = LI
LI = μ₀n²AIl
L = μ₀n²Al

Question 19.
Briefly explain the electromagnetic spectrum.
Answer:
Electromagnetic spectrum is the arrangement of electro magnetic waves in the increasing order of wavelength. Thee.m waves have been arranged in terms of increasing wavelength y-ray, X – ray, Ultraviolet rays,Visible light, Infrared rays, Microwaves, Radio waves.

1. Radio Waves: These have the lowest frequencies and longest wavelengths in the spectrum. They are used for communication, broadcasting, and radar.
2. Microwaves: With slightly higher frequencies and shorter wavelengths than radio waves, microwaves are used in microwave ovens, satellite communication, and certain types of radar.
3. Infrared Radiation: Just beyond the visible spectrum, infrared radiation has frequencies slightly higher and wavelength slightly lower than microwaves.
4. Visible Light: This is the only part of the electromagnetic spectrum that humans can directly perceive with their eyes.
5. Ultraviolet (UV) Radiation: Beyond the visible spectrum, UV radiation has shorter wavelengths and higher frequencies than visible light.
6. X-rays: With even shorter wavelengths and higher frequencies than UV radiation, X-rays are used in medical imaging (X-ray radiography), security scanning, and industrial applications.
7. Gamma Rays: These have the shortest wavelengths and highest frequencies in the spectrum.

Question 20.
Write the postulates of Bohr’s atom model.
Answer:

1. The nucleus of an atom is a small positively charged core where whole of its mass is supposed to be concentrated.
2. The electrons revolve round the nucleus in fixed orbits of definite radii. They do not radiate any energy as long as the electron is in certain orbit.
3. The electrons can revolve only in those orbits, in which its angular momentum is an integral multiple of h/27i. L = mvr = nh/2. where n is known as quantum number of the orbit and h is Planck’s constant.
4. Electron jumps from higher energy orbit to lower energy orbit,by emitting the energy equivalent to the energy gap, in the form of radiations.
   hv = E₂ – E₁

Question 21.
What is a rectifier ? Draw the circuit diagram and input, output wave forms of a full wave rectifier.
Answer:
A rectifier is an electrical device that converts alternating current (AC) into direct current (DC). The process of converting AC to DC is known as rectification. Rectifiers are essential components in various electronic circuits and power supply systems, as many electronic devices required DC power to operate. Rectifiers can be classified into two main types:
Half-Wave Rectifier: This type of rectifier allows only one half of the AC input waveform to pass through to the output, while blocking the other half. It typically consists of a single diode connected in series with the load.

Full-Wave Rectifier: Full-wave rectifiers allow both halves of the AC input waveform to be utilized, resulting in a more continuous DC output.

Answer any 3 questions from 22 to 25. Each carries 4 scores. (3 × 4 = 12)

Question 22.
(a) Complete the diagram with proper marking of direction. (1)

Answer:

(b) Derive the expression for electric field intensity at a point from an infinitely long straight conductor carrying charge. (3)
Answer:

Consider a thin infinitely long straight rod conductor having charge density λ. (λ = \(\frac{q}{I}\))
To find the electric field at P ,we imagine a Gaussian surface passing through P.
Then according to Gauss’s law we can write,
\(\int \overrightarrow{\mathrm{E}} \cdot \mathrm{~d} \overrightarrow{\mathrm{~s}}\) = \(\frac{1}{\varepsilon_0} q\)
\(\int E d s \cos \theta\) = \(\frac{1}{\varepsilon_0} q\) (θ = 0°)
\(E \int d s\) = \(\frac{\lambda I}{\varepsilon_0}\) (Since q = λI)
Integrating over the Gaussian surface, we get (we need not integrate the upper and lower surface because, electric lines do not pass through these surfaces.)
E 2πrI = \(\frac{\lambda I}{\varepsilon_0}\) (L.S.A. of cyhnder = 2πrI)
E = \(\frac{1}{2 \pi r I} \frac{\lambda I}{\varepsilon_0}\)
E = \(\frac{1}{2 \pi \varepsilon_0} \frac{\lambda}{r}\)

Question 23.
(a) State Ohm’s, law. (1)
Answer:
Ohm’s Law states that the current through a conductor between two “points is directly proportional to the potential difference across its ends. Mathematically, we can represent it as V = IR, where V is the potential difference, I is the current, and R is the resistance of the conductor.

(b) Derive Wheatstone’s network principle.
Answer:
Four resistances P,Q,R and S are connected as shown in figure. Voltage ‘V’ is applied in between A and C. Let I₁, I₂,I₃ and I₄ be the four currents passing through P, R,Q and S respectively.

Working
The voltage across R.
When key is closed, current flows in different branches as shown in figure. Under this situation
The voltage across P, V_AB = I₁P
The voltage across Q, V_BC = I₃Q ………(1)
The voltage across R, V_AD = I₂R
The voltage across S, V_DC = I₄S
The value of R is adjusted to get zero deflection in galvanometer. Under this condition,
I₁ = I₃ and I₂ = I₄ ………(2)
Using Kirchoffs second law in loopABDA and BCDB, we get
V_AB = V_AD …………(3)
and V_BC = V_DC ……….. (4)
Substituting the values from eq(1) in to (3) and (4), we get
I₁P = I₂R …………..(5)
and I₃Q = I₄S ………….(6)
Dividing Eq(5)byEq(6)
\(\frac{I_1 P}{I_3 Q}\) = \(\frac{\mathrm{I}_2 \mathrm{R}}{\mathrm{I}_4 \mathrm{~S}}\)
\(\frac{P}{Q}\) = \(\frac{R}{S}\) [since I₁ = I₃ and I₂ = I₄]
This is called Wheatstone condition.

Question 24.
(a) State Snell’s law of refraction. (1)
Answer:
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant.
\(\frac{\sin i}{\sin r}\) = n₂₁
where n₂₁ is a constant, called the refractive index of medium 2 with respect to medium 1.

(b) Explain critical angle and total internal reflection.
Answer:
The angle of incidence for which angle of refraction becomes 90° is called critical angle and total internal reflection is the phenomenon where light travels from denser to rarer medium and the angle of incidence when becomes greater than critical angle, there is no refracted light and all the light is reflected back to the denser medium. This phenomenon is known as total internal reflection.

Question 25.
(a) What are coherent sources? (1)
Answer:
Coherent sources of light are those which have constant their difference between them.

(b) In Young’s double slit experiment, interference pattern is observed at 5 cm from the slits with a fringe width of 1 mm. Calculate the separation between the slits. (k = 500 A) (3)
Answer:
λ = 5000 A
n = 3
D = 1.5 m
wkt,
β = \(\frac{nλD}{d}\)
d = \(\frac{nλD}{ß}\)
= \(\frac{3 \times 5000 \times 10^{-10} \times 1.5}{10^{-2}}\)
= 225 × 10^-6 m
d = 0.0225 cm

Answer any 3 questions from 26 to 29. Each carries 5 scores. (3×5 = 15)

Question 26.
(a) What is the principle of a capacitor? (1)
Answer:
Whenever two neutral conductors are placed nearby, and a potential difference is applied to them, then equal and opposite charges are induced on them.
Therefore, due to these charges, Energy is stored in the form of Electric Field in the gap between them.
A capacitor is device used to store Energy.
The charge appearing on the conductors is directly proportional to the Potential difference applied to them. i.e.
Q ∝ V
⇒ Q = CV
Where C is the constant of proportionality, called capacitance of the system, it depends on physical dimensions of the conductors.

(b) Derive the expression for capacitance of a parallel plate capacitor. (2)
Answer:

Electric field between the plate is given by,
E = \(\frac{\sigma}{\varepsilon_0}\) = \(\frac{Q}{\varepsilon_0 \mathrm{~A}}\) [σ = \(\frac{Q}{A}\)]

Potential difference between the two plates is,
V = Ed = \(\frac{Qd}{\varepsilon_0 A}\)]

Capacitance of capacitor,
C = \(\frac{Q}{V}\) = \(\frac{Q}{\frac{Q d}{\varepsilon_0 A}}\) = \(\frac{{\varepsilon_0 A}}{d}\)

(c) A 12 pF capacitor i connected to 50 V battery. How much electrostatic energy is stored in the capacitor? (2)
Answer:
U = \(\frac{1}{2}\) CV²
= \(\frac{1}{2}\) × 12 × 10^-12 ×50²
= 1.5 × 10^-8 J

Question 27.
(a) The direction of magnetic field around a current carrying conductor is given by . (1)
Answer:
Eight hand thumb rule or right hand grip rule or Maxwell’s Cork screw rule(write name of any one rule).

(b) State Biot-Savart law. (1)
Answer:

The strength of the magnetic field dB is
(i) directly proportional to the current
I, dB ∝ I
(ii) directly proportional to the length
dl, dB ∝ dl
(iii) directly proportional to the sine of the angle (θ) between the element and the line joining the midpoint of the element to the point, dB ∝ sin θ.
(iv) inversely proportional to the square of the distance between the element and the point,
Combining these we get
dB ∝\(\frac{1}{r^2}\)
dB ∝\(\frac{I d l \sin \theta}{r^2}\) = \(\frac{\mu_0}{4 \pi} \frac{I d l \sin \theta}{r^2}\)

(c) Derive the expression for magnetic field on the axis of a circular coil carrying current.(3)
Answer:

Consider a circular loop of radius ‘a’ and carrying current I. Let P be a point on the axis of the coil, at distance x from A and r from ‘O’. Consider a small length dl at A.
The magnetic field at ‘p’ due to this small element dI,
dB = \(\frac{\mu_0 \mathrm{Idl} \sin 90}{4 \pi \mathrm{x}^2}\)
dB = \(\frac{\mu_0 \mathrm{Idl}}{4 \pi \quad \mathrm{x}^2}\) …………..(1)
The dB can be resolved into dB cosϕ (along P_y) and dB sinϕ) (along P_x).
Similarly consider a small element at B, which produces a magnetic field ‘dB’ at P. If we resolve this magnetic field we get.
dB sinϕ (along P_x) and dB cosϕ (along P_y1)
dB cosϕ components cancel each other, because they are in opposite direction. So only dB sinϕ components are found at P, so total field at P is

Question 28.
(a) Write the expression for instantaneous emfofa.c. (1)
Answer:
V = V_m sin t or E = E₀

(b) Identify A, B and C in figure. (1)

Answer:
A – Resistance
B – Inductor
C – Capacitor

(c) Draw the phasor diagram of the above circuit and write the expression for imped-ance in the circuit, then mention the terms. (3)
Answer:

Impendence of the circuit Z is given by
Z = \(\sqrt{\mathrm{R}^2+\left(\mathrm{L} \omega-\frac{1}{\mathrm{C} \omega}\right)^2}\)
R = Resistance, XL = Lω; – inductive reactance, x_c = \(\frac{1}{\mathrm{C} \omega}\) :- Capacitive reactance.

Question 29.
(a) Derive lens maker’s formula. (3)
Answer:
Consider a thin lens of refractive index n₂ formed by the spherical surfaces ABC and ADC. Let the lens is kept in a medium of refractive index n₁. Let an object ‘O’ is placed in the medium of refractive index n₁. Hence the incident ray OM is in the medium of refractive index n1 and the refracted ray MN is in the medium of refractive index n₂.

The spherical surface ABC (radius of curvature R₁) forms the image at I₁. Let ‘u’ be the object distance and V₁ be the image distance. Then we can write,
\(\frac{n_2}{v_1}\) – \(\frac{n_1}{u}\) = \(\frac{n_2-n_1}{R_1}\) ……….(1)
This image I₁ will act as the virtual object for the surface ADC and forms the image at v. Then we can write,
\(\frac{n_1}{v}\) – \(\frac{n_2}{v_1}\) = \(\frac{n_1-n_2}{R_2}\) ……….(2)
Adding eq (1) and eq (2) we get
\(\frac{n_2}{v_1}\) – \(\frac{n_1}{u}\) + \(\frac{n_1}{v}\) – \(\frac{n_2}{v_1}\) = \(\frac{n_2-n_1}{R_1}\) + \(\frac{n_1-n_2}{R_2}\)
\(\frac{n_1}{v}\) – \(\frac{n_1}{u}\) = (n₂ – n₁) (\(\frac{1}{R_1}\) – \(\frac{1}{R2}\))
Dividing throughout by n,, we get
\(\frac{1}{v}\) – \(\frac{1}{u}\) = (\(\frac{n_2}{n_1}\) – 1) (\(\frac{1}{R_1}\) – \(\frac{1}{R2}\))
if the lens is kept in air, \(\frac{n_2}{n_1}\) = n
So the above equation can be written as,
\(\frac{1}{v}\) – \(\frac{1}{u}\) = (n – 1) (\(\frac{1}{R_1}\) – \(\frac{1}{R2}\))
From the definition of the lens, we can take,
when u = ∞, f = v
Substituting these values in the eq (3), we get
\(\frac{1}{f}\) – \(\frac{1}{∞}\) = (n – 1) (\(\frac{1}{R_1}\) – \(\frac{1}{R2}\))
This is lens maker’s formula
\(\frac{1}{f}\) = (n – 1) (\(\frac{1}{R_1}\) – \(\frac{1}{R2}\))

(b) Draw the image formation in a simple microscope. (1)
Answer:

(c) Write the value of least distance of distinct vision. (1)
Answer:
25 cm is the value of least distance of distinct vision.