Plus Two

Reviewing Kerala Syllabus Plus Two Chemistry Previous Year Question Papers and Answers Pdf Board Model Paper 2023 helps in understanding answer patterns.

Kerala Plus Two Chemistry Board Model Paper 2023 with Answers

Time: 2 Hours
Maximum: 60 Scores

Answer any 4 questions from 1 to 5. Each carries 1 score. (4 × 1 = 4)

Question 1.
Identify the order of the reaction if the unit of its rate constant is mol L^-1 s^-1.
Answer:
Zero Order

Question 2.
Zirconium and Hafnium have similar chemical properties. This is due to ______________
Answer:
Lanthanoid Contraction

Question 3.
Give an example for a polydentate ligand.
Answer:
EDTA

Question 4.
Which among the following compounds do not contain an alpha hydrogen?
(a) Propanone
(b) Ethanal
(c) Ethanol
(d) Benzaldehyde
Answer:
Benzaldehyde

Question 5.
A polyhalogen compound is ______________
(a) Chloroform
(b) Chlorobenzene
(c) Chloroethane
(d) Iodobenzene
Answer:
(a) Chloroform

Answer any 8 questions from 6 -15. Each carries 2 scores. (8 × 2 = 16)

Question 6.
(i) State RaouIt’s Law. (1)
(ii) Give an example for a solution which shows positive deviation from Raoult’s law. (1)
Answer:
(i) For a solution of volatile liquids, the partial vapour pressure of each component of the solution is directly proportional to its mole fraction present in solution.
\(\mathrm{P}_{\mathrm{A}}=\mathrm{P}_{\mathrm{A}}^0 \mathrm{X}_{\mathrm{A}}\)
(ii) Ethanol + Acetone

Question 7.
What are isotonic solutions? Give an example.
Answer:
Solutions with the same osmotic pressure are called isotonic solutions.
Eg. Blood and 0.9% normal saline solution

Question 8.
Write the anode reaction, cathode reaction, and net cell reaction of Daniel Cell.
Answer:
Daniel Cell
Anode: Zn → Zn²⁺ + 2e^–
Cathode: Cu²⁺+ 2e^– → Cu
Net Reaction: Zn + Cu²⁺ + 2e^– → Zn²⁺ + Cu
Zn + Cu²⁺ → Zn²⁺ + Cu

Question 9.
A first order reaction has a rate constant 1.15 × 10^-3 s^-1. How long will it take for 5 g of the reactant to decrease to 3g?
Answer:

Question 10.
Write the IUPAC name of the following coordination compounds.
(a) K3[Fe(CN)₆] (1)
(b) [Ni(CO)₄] (1)
Answer:
(a) Potassium Hexacyano Ferrate (III)
(b) Tetra Carbonyl Nickel (0)

Question 11.
Chloroform is stored in closed, dark coloured bottles filled up to the neck. Why?
Answer:
Chloroform reacts with oxygen to form a poisonous compound, phosgene (Carbonyl Chloride).

Question 12.
Phenols are acidic. Give reason.
Answer:
Acids are those substances which can release H⁺ easily. Phenol releases H⁺ easily and the phenoxide ion is more stabilised by resonance.

Question 13.
What is meant by diazotization reaction?
Answer:
Aniline on treatment with sodium nitrite and Con. HCl in ice-cold condition gives benzene diazonium chloride. This is known as diazotisation.

Question 14.
Most transition metals from coloured compounds. Why?
Answer:
Due to d-d transition.
The transition of d electron occurs between (n-1)d orbitals.

Question 15.
Write two differences between DNA and RNA.
Answer:

DNA	RNA
(i) Deoxyribonucleic acid.	(i) Ribonucleic acid.
(ii) Double helix structure.	(ii) Single helix structure.
(iii) Nitrogen bases A, T, C, G are present.	(iii) Nitrogen bases A, U, C, G are present.
(iv) Controls hereditary factors.	(iv) Controls synthesis of proteins.

Answer any 8 questions from 16-26. Each carries 3 scores. (8 × 3 = 24)

Question 16.
(i) Which of the following is a secondary cell? (1)
(a) Daniel cell
(b) Dry cell
(c) Lead storage battery
(ii) What is a fuel cell? (1)
(iii) Write the overall cell reaction of a H₂ – O₂ fuel cell. (1)
Answer:
(i) Lead storage battery.
(ii) Fuel cells are a galvanic cell that convert the energy of combustion of fuels into electrical energy.
Eg. H₂ – O₂ fuel cell
(iii) 2H₂ + O₂ → 2H₂O

Question 17.
The effect of temperature on the rate of a reaction is given by the Arrhenius equation.
(i) Write the Arrhenius equation. (1)
(ii) Define activation energy. (1)
(iii) Write the integrated rate expression for a zero order reaction. (1)
Answer:
(i) k = \(\mathrm{Ae}^{-\mathrm{Ea} / \mathrm{RT}}\)
where k is rate constant
A – Arrhenius factor
E_a – Energy of activation
R – Universal gas constant
T – Temperature.
(ii) The excess energy supplied to the reactant molecule to undergo chemical reaction is called activation energy.
(iii) k = \(\frac{\left[R_0\right]-[R]}{r}\)
k = rate constant
R₀ = initial concentration
R = final concentration
t = time

Question 18.
Hydrolysis of ester is a pseudo first order reaction.
(i) What do you mean by a pseudo first order reaction? (1)
(ii) The moiecularity of the reaction 2NO + O₂ → 2NO₂ is ______________ (1)
(iii) The rate expression for a reaction is k = [A]² [B]^1/2. Find the order of the reaction. (1)
Answer:
(i) Reactions that appear to be of higher order but behave as first order reactions are called pseudo first order reactions.
(ii) 2 + 1 = 3
No. of molecules taking part in the reaction.
(iii) Order = 2 + \(\frac{1}{2}\) = 2\(\frac{1}{2}\) = \(\frac{5}{2}\)

Question 19.
(i) Mention the industrial preparation of KMnO₄ from MnO₂. (2)
(ii) Draw the structure of Dichromate ion. (1)
Answer:
(i) It is prepared by fusion of MnO₂ with KOH. K₂MnO₄ is produced first. This is then disproportionate in acidic solution to give KMnO₄ by electrolytic oxidation.

Question 20.
(i) Explain one difference between double salt and a coordination compound? (2)
(ii) What is the co-ordination number of nickel in [Ni(CN)₄]^2-? (1)
Answer:
(i) Double Salt: Dissociate into simple ions completely in aqueous solution. These salts exist in the solid state only.
Coordination Compound: Do not dissociate into simple ions. Exist in solid state as well as in solution.
(ii) 4

Question 21.
(i) Mention two reactions that show the acidic character of alcohols. (2)
(ii) Name the product obtained when phenol is treated with a mixture of concentrated HNO₃ and concentrated H₂SO₄. (1)
Answer:
(i) CH₃ – CH₂OH + Na → CH₃CH₂ONa
ethanol + metallic sodium → sodium ethoxide

Question 22.
Explain the hydroboration oxidation reaction of propene with the help of a chemical equation. (3)
Answer:
Hydroboration is Antimarkonikov’s addition of water.

Question 23.
Identify X, Y, Z in the following reactions:

Answer:

Question 24.
(i) How can you prepare Benzaldehyde by Etard reaction? (1½)
(ii) Identify the product obtained by the reaction between acetic acid and ethanol? What is the name of this reaction? (1½)
Answer:
(i) Etard’s Reaction: Toluene on reaction with chromyl chloride followed by hydrolysis gives benzaldehyde.

(ii) Esterification Reaction

Question 25.
(i) What is Hinsberg Reagent Chemically? (1)
(ii) What is it used for? Explain your answer. (2)
Answer:
(i) Benzene sulphonyl chloride
(ii) To distinguish primary, secondary and tertiary amines.
Primary Amine + Hinsberg reagent → Salt soluble in alkali
Secondary Amine + Hinsberg reagent → Salt insoluble in alkali
Tertiary Amine + Hinsberg reagent → No reaction

Question 26.
(i) Name a fat-soluble vitamin? Which disease is caused by its deficiency? (2)
(ii) Name the enzyme used for the conversion of sucrose to glucose and fructose. (1)
Answer:
(i) A
Xerophthalmia
(ii) Invertase

Answer any 4 questions from 27 to 31. Each carries 4 scores. (4 × 4 = 16)

Question 27.
Abnormal values are obtained for certain solutes during the determination of molecular mass by colligative property method.
(i) Mention two reasons for the abnormal molecular mass values. (1)
(ii) How can this abnormal molecular mass be corrected? Substantiate your answer. (2)
(iii) Write any one application of reverse osmosis. (1)
Answer:
(i) Dissociation or association of solute particles.
(ii) Applying Van’t Hoff factor (i) to colligative properties
\(\mathrm{i}=\frac{\text { observed colligative property }}{\text { normal colligative property }}\)

1. Relative lowering of vapour pressure \(\frac{\Delta \mathrm{p}}{\mathrm{p}^0 \mathrm{~A}}=\mathrm{i} \frac{\mathrm{n}_{\mathrm{B}}}{\mathrm{n}_{\mathrm{A}}}\)
2. Elevation in boiling point ΔT_b = i k_b.m
3. Depression in freezing point ΔT_f = ik_f.m
4. Osmotic pressure π = \(\mathrm{i} \frac{\mathrm{n}}{\mathrm{v}} \mathrm{RT}\)

(iii) Desalination of sea water.

Question 28.
(i) Define galvanic cell. (1)
(ii) Corrosion may be considered as an electrochemical process. Why? (2)
(iii) Mention two ways to prevent corrosion. (1)
Answer:
(i) A device which converts chemical energy to electrical energy is known as an electrochemical cell or galvanic cell.
(ii) Pure iron acts as anode
At anode
2Fe(s) → 2Fe²⁺ + 4e^–
Electrons produced move through the metal and go to the cathode (impure surface) and reduce O₂ in the presence of H⁺.
H⁺ ions are formed by the dissolution of CO₂ in moisture.
At cathode: 4H⁺ (aq) + O₂ (g) + 4e^– → 2H₂O (l)
Overall reaction is 2Fe (s) + O₂ (g) + 4H⁺ (aq) → 2Fe²⁺ (aq) + 2H₂O (l)
Ferrous ions so formed are oxidised by atmospheric oxygen to ferric ions.
2Fe²⁺ + 2H₂O + \(\frac{1}{2}\)O₂ → Fe₂O₃ + 4H⁺
Fe₂O₃ + xH₂O → Fe₂O₃.xH₂O rust hydrated ferric oxide
(iii) (1) Applying paint or grease
(2) Coating with another active metal.

Question 29.
(i) Draw the geometrical isomers of [Pt(NH₃)₂Cl₂] and label them as cis and trans. (2)
(ii) Explain homoleptic and heteroleptic complexes. (2)
Answer:
(i)

(ii) Homoleptic complexes: Complexes in which only one type of ligand is used.
Eg: [Co(NH₃)₆]³⁺
Heteroleptic Complexes: Complexes in which more than one type of ligand is used.
Eg: [Co(NH₃)₄Cl₂]⁺

Question 30.
(i) Explain the Friedel-Crafts alkylation reaction of chlorobenzene. Mention the major product in this reaction. (2)
(ii) Identify X and Y in the reaction given below. (1)

Answer:
(i)

Chlorobenzene on treatment with methyl chloride in presence of anhydrous AlCl₃ gives a mixture of P-chloro toluene and O-chlorotoluene.

Question 31.
Explain the following reactions.
(i) Cannizzaro’s reaction (1½)
(ii) Aldol condenstion (1½)
(iii) Which among CH₃COOH and CH₂ClCOOH is more acidic? (1)
Answer:
(i) Cannizzaro Reaction: Aldehydes which do not contain a hydrogen undergo self oxidation and reduction to form acid salt and alcohol in presence of concentrated alkali.


(ii) Aldol condensation: Aldehydes or ketones with α-H atom undergo condensation to form β-hydroxy aldehyde or aldol in presence of dilute alkali.

(iii) CH₂ClCOOH due to – I effect.

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.

 

Reviewing Kerala Syllabus Plus Two Computer Science Previous Year Question Papers and Answers Pdf March 2023 helps in understanding answer patterns.

Kerala Plus Two Computer Science Previous Year Question Paper March 2023

Time: 2 Hours
Total Score: 60 Marks

Part – I

Answer any 5 questions from 1 to 6. Each car-ries 1 score. (5 × 1 = 5)

Question 1.
In C++ ___________ operator is used to get the address of a memory location.
Answer:
& (address operator)

Question 2.
In ___________ data structure, the element added at last will be removed first.
Answer:
Stack

Question 3.
In HTML ___________ tag is used to create hyperlink.
Answer:
<a> or <A> or Anchor tag

Question 4.
To transfer the files of the website from our computer to the web server ___________ software is used.
Answer:
FTP Client Software (FileZilla,CuteFTP, SmartFTP)

Question 5.
In RDBMS, the minimal set of attributes that uniquely identifies a row in a relation is called ___________
Answer:
Candidate key

Question 6.
Expand DDoS.
Answer:
Distributed Denial of Service

Part – II

Answer any 9 questions from 7 to 18. Each carries 2 scores. (9 × 2 = 18)

Question 7.
Write any two features of dynamic memory allocation.
Answer:

• In dynamic memory allocation, the amount of memory to be allocated is not known in advance.
• It is allocated during run time as and when required using new operator.

Question 8.
Briefly explain about POP operation in a STACK data structure.
Answer:
POP operation: It is the process of deleting(removing) a data item from the stack. If the stack is empty and we try to delete an item from the stack makes the stack underflow.

Question 9.
Describe about QUEUE data structure
Answer:
The working principal of a queue is First In First Out (FIFO) manner. A new data item is added at the rear and removed from the front of a queue.

Question 10.
What are the features of Dynamic Web Page?
Answer:
Dynamic web page

1. Its content and layout is changed frequently
2. It uses database
3. Not at all easy to develop.

Question 11.
List the values of Type attribute of <INPUT> tag.
Answer:
Values are text, password, radio, checkbox, reset, submit and button.

Question 12.
Write any two built in – Functions used in JavaScript.
Answer:
alert(),isNaN(),charAt(),toUpperCase (), toLowerCase(),etc

Question 13.
Write short note about virtual private server.
Answer:
It is a combination of dedicated hosting and shared hosting. It is virtually partitioned into more servers using the virtualization technology like shared hosting. But it provides dedicated bandwidth to each website on the server like dedicated hosting. This is suitable for websites that require more features than shared hosting but less features than dedicated hosting.

Question 14.
What is free hosting?
Answer:
The name implies it is free of cost service and the expense is meet by the advertisements. Some service providers allow limited facility such as limited storage space and do not allow multimedia files.

Question 15.
Write short note about constraints in SQL.
Answer:
(a) NOT NULL: it specifies that a column can never have null values, i.e., not empty.

(b) UNIQUE: it ensures that no two rows have same value in the specified column.

(c) PRIMARY KEY: it declares a column or a set of columns as the primary key of the table. This constraint makes a column NOT NULL and UNIQUE.

(d) DEFAULT: it sets a default value for a column when the user does not enter a value for that column.

(e) Auto_ncrement: This constraint is used to perform auto_increment the values in a column. That is automatically generate serial numbers. Only one auto_ncrement column per table is allowed.

Question 16.
Distinguish between DROP and DELETE commands used in SQL.
Answer:

DROP	DELETE
• It is a DDL command	• It is a DML command
• It is used to remove a table from the database	• It is used to remove one or more rows from the table

Question 17.
Differentiate between serial and parallel computing.
Answer:

Serial computing	Parallel computing
• A single processor is used.	• Multiple processors are used with shared memory
• A problem is divided into a series of instructions	• A problem is divided into smaller ones that can be solved simultaneously
• Instructions executed sequentially	• Instructions executed simultaneously
• One instruction is executed on a single processor at any moment.	• More than one ‘ instruction is executed on multiple processors at any moment of time.

Question 18.
List any four applications of computational intelligence.
Answer:
A) Biometrics : Biometrics refers to the unique characteristics of a human being to recognize an individual such as finger prints, face recognition, iris, retina etc. Biometrics are used to record attendance Eg. In banks employee login is restricted by using finger print reader.

B) Robotics : It is a branch of scientific study associated with the design, manufacturing and control the movements of the robots. Roboticss are used in all the areas. Some of them are discussed below.

C) Computer vision: The world is changed from 2 dimensional images to 3 dimensional. 3D TVs are available in the market. Multiple cameras are used to capture the images and merge them to form 3D pictures. 3D scanners are used in the Medical field to diagnose the diseases

D) Natural Language Processing : It deals with how computers are communicate just like a human being communicate naturally. Natural languages are languages spoken by the people. To achieve this ability to communicate like a human being is a laborious task. NLP is further be classified into two, Natural Language Understanding (NLU) and Natural Language Generation (NLG)
NLU-The ability to understand the languages like English, Malayalam, etc.
NLG- It is deal with creation of output, i.e. generate words and giving reply.

Part – III

Answer any 9 questions from 19 to 29. Each carries 3 scores. (9 × 3 = 27)

Question 19.
Differentiate between array and structure.
Answer:

Structures	Array
• It is a user defined datatype.	• Predefined data type.
• It is a collection of different types of logically related data under one name.	• Collection of data elements of same data type having a common name.
• Elements referenced using dot operator (.).	• Elements references using its subscripts (position value).
• When an element of a structure becomes another structure nested structure and complex structures are formed.	• When an element of another becomes another array, multidimensional arrays are formed.
• Structures contains array as its elements.	• Array of structure can be formed.

Question 20.
Write short note about polymorphism.
Answer:
Polymorphism : It is the ability for a message or data to be processed in more than one form. This is achieved by function overloading, operator overloading and dynamic binding.

Question 21.
Briefly explain about any two attributes of <BODY> tag.
Answer:
Web page contents are given int the body section. Attributes of body tag are:
1) BGCOLOR-Specifies background color for the document Body
Eg. <BODY BGCOLOR= “RED”>

2) BACKGROUND -Sets the image as background for the document body
Eg.<BODYBACKGROUNG=“C:\result.jpg”>

3) TEXT-Specifies the color of the text content of the page
Eg. <BODY TEXT= “Red”>

4) LINK- Specifies colour of the hyperlinks that are not visited by the user

5) ALINK-Specifies the colour of hyperlinks

6) VLINK-Specifies the color of hyperlinks which are already visited by the viewer.
Eg. < BODY ALINK= “Cyan” LINK=” Magenta” VLINK= “Orange”>

7) Leftmargin and Right margin-Sets margin from left ‘ and top of the document window.

Question 22.
Write short note about the tags used to create a table in HTML.
Answer:
Following are the Tags used to create a table in HTML

1. <table> – Used to create a table.
2. <tr> – Used to create a row
3. <th> – Used to create heading cells
4. <td> – Used to create data cells

Question 23.
Differentiate between ordered and unordered lists in HTML.
Answer:
Ordered List (<OL>) – Items are displayed with the following type values.
Type = 1 for 1, 2, 3,
Type = i for i, ii, iii, ……..
Type = I for I, II, III
Type = a for a, b, c,
Type = A for A, B, C,
Unordered List (<UL>) – Items are displayed with square, circle or disc in front.

Question 24.
Write short note about Data types in JavaScript. JavaScript
Answer:
Unlike C++ it uses only three basic data types

1. Number: Any number(whole or fractional) with or without sign.
   Eg: +1977,-38.0003,-100, 3.14157,etc
2. String: It is a combination of characters enclosed within double quotes.
   Eg: “BVM”, “jobi_cg@rediffmail.com”, etc
3. Boolean : We can store either true or false. It is case sensitive. That means can’t use TRUE OR FALSE

Question 25.
Briefly explain about any two control structures in JavaScript.
Answer:
In general the execution of the program is sequential, we can change the normal execution by using the control structures.
■ Simple if’

Syntax:
if(test expression)
{
statements;
}

First the test expression is evaluated, if it is true then the statement block will be executed otherwise not.

* if-else
Syntax:
if(test expression)
{
statement block 1;
}
else
{
statement block2;
}

First the test expression is evaluated, if it is true then the statement blockl will be executed other wise statement block2 will be evaluated.

■ Switch
It is a multiple branch statement. Its syntax is given below.

switch(expression)
{
case value1: statements;break;
casevalue2: statements;break;
case value3: statements;break;
case value4: statements.break;
case value5: statements;break;
..................
default : statements;
}

First expression evaluated and selects the statements with matched case value.

■ for loop
The syntax of for loop is given below For(initialisation; testing; updation)

{
Body of the for loop;
}

■ while loop
It is an entry controlled loop The syntax is given below Loop variable initialised

while(expression)
{
Body of the loop;
Update loop variable;
}

Here the loop variable must be initialised out side the while loop. Then the expression is evaluated if it is true then only the body of the loop will be executed and the loop variable must be updated inside the body. The body of the loop will be executed until the expression becomes false.

Question 26.
Write short note about following terminologies in RDBMS:
(a) Relation
(b) Domain
(c) Foreign key
Answer:
a) Relation means table
b) Domain – A pool of possible values from which column values are drawn.
c) Foreign key – A single or a set of attributes, which is a candidate key in another table is called foreign key.

Question 27.
Write short note about data types in SQL.
Answer:

1. Char – It is used to store fixed number of characters. It is declared as char(size).
2. Varchar – It is used to store characters but it uses only enough memory.
3. Dec or Decimal – It is used to store numbers with decimal point. It is declared as Dec (size, scale). We can store a total of size number of digits.
4. Int or Integer – It is used to store numbers with-out decimal point. It is declared as int. It has no argument. Eg: age int.
5. Smallint – Used to store small integers.
6. Date – It is used to store date. The format is yyyy- mm-dd. Eg:‘1977 – 05 – 28’.
7. Time – It is used to store time: The format is
   HH:MM:SS
   Eg. ‘10:05:25’

Question 28.
Briefly explain about operators in PHP.
Answer:
Operators are the symbols used to perform an operation

a) Assignment operator(=)
The value of RHS is assigned to LHS variable.
If $a=10 and $b=3 then $a=$b. This statement sets the value of $a and $b are same ,i.e. it sets a to 3.

b) Arithmetic operators
It is a binary operator. It is used to perform addition(+), subtraction(-), division (/), multiplication(*) ,modulus(%-gives the remainder).
Eg. If $x=10 and $y=3 then

c) Relational (Comparison) operators
It is used to perform comparison or relational operation between two values and returns either true or false.
Eg: If $X= 10 and $Y=3 then

d) Logical operators
Here (and , &&), (or, ||), xorare binary operators and not(!) is a unaryoperator. It is used to combine relational operations and it gives either true or false
lf$X=trueand$Y=falsethen

Both operands must be true to get a true value in the case of && operation
If $X=true and $Y=false then

Both operands must be true to get a true value in the case of ‘and’ operation lf$X=trueand$Y=falsethen

Either one of the operands must be true to get a true value in the case of || operation
If $X=true and $Y=false then

Either one of the operands must be true to get a true value in the case of or operation
If$X=trueand $Y=falsethen

Either one of the operands must be true to get a true value in the case of xor operation
If $X= true and $Y=false then

!$X	!$Y
false	true

e) String addition operator(‘.’, ‘.=’)
This is also called concatenation operator. It joins(concatenates) two strings and forms a string. They are ‘.’ and ‘.=’.
Eg:
$x= “BVM HSS”;
$y= “ Kalparamba”;
$z=$x.$y;
• Here the variable z becomes “BVM HSS Kalparamba”.
$x.=$y;
• Here the variable $x becomes “BVM HSS Kalparamba”.

f) Combined operators.
It is also called short hands If $X=10 and $Y= 3 then

g) Increment and decrement operators.
1) pre increment (++variable)
Eg:
If $x=10then
echo(++$x); -> It prints 10+1=11

2) post incrempnt (variable++)
lf$x=10then
echo($x++); -> It prints 10 itself.

3) pre decrement—variable)
If $x=10 then
echo(-$x); It prints 10-1=9

4) post decrement(variable-)
lf$x=10then
• echo($x-);-> It prints 10 itself.

Question 29.
Explain about the types of interactions in e-Govemance.
Answer:
Types of interactions in e-Governance
e-Governance facilitates interaction between different stakeholders in governance

• Government to Government (G2G)
• Government to Citizens (G2C)
• Government to Business (G2B)
• Government to Employees(G2E)

Part – IV

Answer any 2 questions from 30 to 32. Each carries 5 scores. (2 × 5 = 10)

Question 30.
(a) Write the basic structure of a HTML document. (3)
(b) List any two text formatting tags. (2)
Answer:
(a) Basic structure of an HTML Document

<HTML>
<HEAD>
<TITLE>
Give a title to the web page Here
</TITLE>
</HEAD>
<BODY>
This is the body Section.
</BODY>
</HTML>

(b) <B> to make the content Bold
<I>to make the content Italic

Question 31.
(a) List any four advantages of DBMS. (2)
(b) Write short note about any two operations on relational algebra. (3)
Answer:
a) Advantages of e-Business

• Data Redundancy – It means duplication of data. DBMS eliminates redundancy. DBMS does not store more than one copy of the same data.
• Inconsistency can be avoided – If redundancy occurs there is a chance to inconsistency. If redundancy is removed then inconsistency cannot occur.
• Efficient data access It stored huge amount of data efficiently and can be retrieved whenever a need arise.
• Data can be shared – The data stored in the database can be shared by the users or programs.
• Standards can be enforced – The data in the database follows some standards. Eg: a field ‘Name’ should have 40 characters long. Some standards are ANSI, ISO, etc.
• Security restrictions can be applied – The data is of great value so it must be kept secure and private. Data security means the protection of data against accidental or intentional disclosure or unauthorized destruction or modification by unauthorized person.
• Integrity can be maintained – It ensures that the data is to be entered in the database is correct.
• Crash recovery – Some times all or a portion of the data is lost when a system crashes. A good DBMS helps to recover data after the system crashed.

b) Relational algebra operations
A) SELECT operation
SELECT operation is used to select tuples in a relation that satisfy a selection condition. Greek letter CT (sigma) is used to denote the operation.
Syntax,
σ_condition(relation)
eg. a_{salary < 10000} (EMPLOYEE)-selects tuple whose salary is less than 10000 from EMPLOYEE relation.

B) PROJECT operation
PROJECT operation selects certain columns from the table and discards the other columns. Greek letter n(pi) is used to denote PROJECT operation.
Syntax, π_condition (relation)
eg.π_{name, salary} (EMPLOYEE) displays only the name and salary of all employees

C) UNION operation
This operation returns a relation consisting of all tuples appearing in either or both of the two specified relations. It is denoted by U. duplicate tuples are eliminated. Union operation can take place between compatible relations only, i.e., the number and type of attributes in both the relations should be the same and also their order. e.g. SCIENCE U COMMERCE gives all the tuples in both COMMERCE and SCIENCE.

D) INTERSECTION operation
This operation returns a relation consisting of all the tuples appearing in both of the specified relations. It is denoted by n. It can takes place only on compatible relations, e.g. FOOTBALL & CRICKET returns the players who are in both football and cricket teams.

Question 32.
(a) What are the advantages of e-Business? (2)
(b) Explain about e-Learning tools. (3)
Answer:
a) Advantages of e business

• It overcomes geographical limitations
• It reduces the operational cost
• It minimizes the time and cost
• It remains open all the time
• We can locate the product faster from a wider range of choices

b) e Learning tools
a) Electronic books reader(e Books)
With the help of a tablet or portable computer or any other device we can read digital files by using-a s/w is called electronic books reader.

b) e text
The electronic format of textual data is called e-Text.

c) Online chat
Real time exchange of text or audio or video messages between two or more person over the Internet.

d) e Content
The data or information such as text, audio, video, presentations, images, animations etc, are stored in electronic format.

e) Educational TV channels
TV channels dedicated only for the e-Leaming purpose : Eg. VICTERS (Virtual Class room Technology on Edusat for Rural Schools OR Versatile ICT Enabled Resources for Students)

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

Kerala Plus Two Zoology Question Paper March 2021 with Answers

Answer the following questions from 1 to 31 upto a maximum score of 30. (7 × 1 = 7)
I. Each question from 1 to 7 carries 1 score.

Question 1.
Name the oral contraceptive for female developed by CDRI.
Answer:
Saheli

Question 2.
Name the genetic’disorder in which a blood clotting protein is affected leading to non-stop bleeding even through a simple wound.
Answer:
Haemophilia

Question 3.
Under microscope, chromatin is seen as ‘beads-on-string’ like structure. Here, ‘beads’ represent the structures called.
Answer:
Nucleosome

Question 4.
During luteal phase of menstrual cycle, Graafian follicle transforms into
Answer:
Corpus luteum

Question 5.
Organic pollutants in sewage water is measured as
(a) GMO
(b) MPT
(c) BOD
(d) HGP
Answer:
BOD

Question 6.
Select an example for homologous organs.
(a) Eyes of octopus and mammals
(b) Forelimbs of Whales and Bats
(c) Flippers of Penguins and Dolphins
(d) Wings of Birds and Butterflies
Answer:
Forelimbs of Whales and bats

Question 7.
Enzyme used in detergents for removing oily stains from laundry is _____.
(a) Lipase
(b) Protease
(c) Amylase
(d) Pectinase
Answer:
Lipase

II. Each question from 8 to 26 carry 2 scores. (19 × 2 = 38)

Question 8.
‘In a cell, euchromatin and Heterochromatin can be observed under microscope’. Distinguish between euchromatin and Heterochromatin.
Answer:

Euchromatin	Heterochromatin
i) It is loosely packed.	It is densely packed.
ii) It is Trascriptionally active.	It is Transcriptionally Inactive.

Question 9.
Presence of an additional copy of chromosome 21 was observed in a person during diagnosis.
(a) Identify the genetic disorder
(b) Write the characteristic features of this disorder.
Answer:
(a) Down’s Syndrome

(b) 1. Short stature and small round head,
2. Furrowed tongue and partially open mouth

Question 10.
Fill in the blanks to complete the table:

Micro-organism	Use of Micro-organism
i. (a) _____	Curding of Milk
ii. Bacillus thuringiensis	(b) ______
iii. Aspergillus niger	(c) ______
iv. (d) ______	Production of butyric acid

Answer:
(a) Lactic acid bacteria
(b) Control butterfly catterpillars
(c) Citric acid
(d) Clostridium butylicum

Question 11.
If a father is with ‘O’ blood group and mother is with ‘B’ blood group, write the possible blood groups of their children.
Answer:
‘B’ group and ‘O’ roup

Question 12.
Observe the figure

(a) Identify the molecular strucuture given in the figure.
(b) Name the regions labelled as A, B and C.
Answer:
(a) Antibody or Immunoglo’bulins
(b) A – Antigen binding site
B – Light chain
C – Heavy chain

Question 13.
In eukaryotes, gene expression can be regulated at several levels. Write diffèrent levels at which gene expression can be regulated.
Answer:
(i) Transcriptional level
(ii) Translational level

Question 14.
Expand the following terms related with Assisted Reproductive Technologies:
Answer:
(a) Intra Cytoplasmic Sperm Injection
(b) Gamete Intra Fallopian Transfer

Question 15.
Fill in the blanks to complete the schematic repre sentation.

Answer:
(a) Lippes loop
(b) Multiloäd 375
(c) LNG-20
(d) Progestasert

Question 16.
Write any four objectives of Reproductive and Child Health Care (RCH) programmes.
Answer:

1. Creating awareness among people about various reproduction related aspects.
2. Providing facilities and support for building up a reproductively healthy society.
3. Provide right information to the young so as to discourage children from believing in myths and
   having misconceptions about sex-related aspects.
4. Proper information about reproductive organs, adolescence and related changes, safe and hygienic sexual practices, sexually transmitted diseases.

Question 17.
‘Now-a-days, the world is facing a problem of increased rate of species extinction due to huma
activities’. Write major causes of biodiversity losses.
Answer:

1. Habitat loss and fragmentation
2. Over-exploitation
3. Alien špecies invasion
4. Co-extinctions

Question 18.
Drug/Alcohol abuse results in immediate and far reaching effects. Write some effects you have studied.
Answer:

1. Use of alcohol causes stomach ulcer and pancreatitis.
2. Causes lack of interest in personal hygiene, isolation, depression, aggressiveness etc.
3. Causes deteriorating relationship with family and friends change in eating and sleeping habit.
4. The excess usage of alcohol causes liver cirrhosis and damage to nervous system.

Question 19.
Evolution of Darwin finches in an example for ‘Adaptive radiation’.
(a) What is meant by ‘Adaptive radiation’?
(b) Give two other example for organisms those exhibitAdaptive radiation.
Answer:
(a) The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of habitat is called adaptive radiations.

(b) Marsupia[ mammal in Australia & Placental mammals.

Question 20.
Write any four differences between Spermatogenesis and Oogenesis.
Answer:

Spermatogenesis	Oogenesis
1. Four sperms from one primary from spermatocyte.	1. It is the process of formation of ovum oregg.
2. It is the process of formation of sperms.	2. It take place in ovary.
3. It take place in male.	3. It take place in female.
4. It take place in testis.	4. Starts in embryonic stage.

Question 21.
Micrograph of Red blood cells of two persons (A) and (B) are shown below. Person B is affected with
a specific genetic disorder.
(i) Identify the genetic disorder.
(ii) Write reason for this disorder.

Answer:
(i) Sickle-cell anemia
(ii) The defect is due to substitution of glutamic acid (Glu) by valine (Val) at sixth position of beta globulin chain of haemoglobin.

Question 22.
In women, some hormones are secreted only durng pregnancy. Name any such hormones.
Answer:

1. Human chorionic gonadotropin (hCG)
2. Human placental lactogen (hPL)

Question 23.
Match following:

A	B
i. L.H. Surge	Fertilisation
ii. Leydig cells	Nutrition to
iii. Ampullary-isthmic junction	Spermatids
iv. Sertoli cells	Ovulation

Answer:

A	B
i. L.H. Surge	Ovulation
ii. Leydig cells	Androgens
iii. Ampullary-isthmic junction	Fertilisation
iv. Sertoli cells	Nutrition to Spermatids

Question 24.
“Species diversity is greater in tropical regions than in temperate regions.” Give reasons.
Answer:
Tropical environment are more constant and predictable. Solar energy is more in tropical area than temperate area.

Question 25.
Vaccines are given to children at various stages of their development.
(a) What is meant by ‘vaccine’?
(b) Write the principle of vaccination.
Answer:
(a) Vaccines are preparation of antigenic proteins of pathogen or inactivated or weakened pathogen
(b) Property of memory of the immune system

Question 26.
Match following:
Answer:

1. 1^st month – Heart sound is noticed using stethescope.
2. 2^nd month – Limbs and digits are developed in foetus
3. 5^th month – First movement of foetus is observed
4. 6^th month – Eye lids are separated and eye lashes are formed

III. Each question from 27 to 31 carries 3 scores. (5 × 3 = 15)

Question 27.
(a) Identify the equation related with genetic equilib rium given below:
p² + 2pq + q² = 1
(b) Write the factors affecting genetic equilibrium resulting in evolution.
Answer:
(a) Hardy Weinberg Equilibrium
(b) Gene flow ,Genetic drift, Mutation and Natural selection

Question 28.
LH and FSH play significant role in spermatogenesis.
(a) Write the funchons of LH and FSH in spermato genesis.
(b) Write a single term used to denote LH and FSH together.
Answer:
(a) LH – Act on the Leydig cell and stimulate t he production of and rogens
FSH – Acton Sertoli cells and stimulates some factors which help in spermatogenesis.

(b) Gonadotropins

Question 29.
Figure of ‘lac operon’ in the absence of lactose (inducer) is given below. Draw the diagram of ‘lacoperon’ in the presence of lactose and label it.

Answer:

Question 30.
SexuallyTransmitted Diseases (STDs) are seen to be high among people with age group 15 -24 yrs.
(a) Write the names of any 4 STDs
Answer:
(a)

1. AIDS
2. Genital Herpes
3. Genital Warts
4. Trichomoniasis

(b)

1. Avoid sex with unknown partner
2. Always use condoms during coitus
3. In case of doubt consult a doctor for diagnosis and treatment

Question 31.
‘Incomplete Dominance’ is an example for deviation from Mendelian Inheritance. Illustrate with example.
Answer:
It is the inheritance in which the heterozygous offspring show intermediate character between two parents. Cross given below shows the genotypic and phenbtypic ratio in F₁ and F₂ generation.

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

Kerala Plus Two Computer Science Previous Year Question Paper March 2024

Time: 2 Hours
Total Score: 60 Marks

Answer any 5 questions from 1 to 6. Each carries 1 score. (5 × 1 = 5)

Question 1.
Choose the indirection or value at operator used in C++ from the options given below.
(a) ++
(b) *
(c) &
(d) +
Answer:
(b) *

Question 2.
Which of the following is used for creating controls in a form in HTML?
(a) <TABLE>
(b) <OL>
(c) <INPUT>
(d) <FRAME>
Answer:
(c) <INPUT>

Question 3.
Name the type of web hosting in which client leases the entire Webserver and it’s resources.
Answer:
Dedicated hosting

Question 4.
The smallest unit of stored data in DBMS is called …………………….
Answer:
Field or Attribute

Question 5.
The full form of DML is ………………..
Answer:
Data Manipulation Language

Question 6.
Legal right given to the creators for an original work is
(a) Geographical indication
(b) Trademark
(c) Copyright
(d) Industrial design
Answer:
(c) Copyright

Answer any 9 questions from 7 to 18. Each carries 2 scores. (9 × 2 = 18)

Question 7.
Write the syntax for the following :
(a) Declaration of pointer variable in C++
(b) Dynamic memory allocation in C++
Answer:
(a) data_type*variable;
(b) pointer = new data_type;

Question 8.
Define the term self – referential structure, Give example.
Answer:
Self-referential structure: A structure contains an element that is a pointer to the same structure.

Question 9.
Write any two advantages of using OOP.
Answer:

• OOP allows modularity
• It is good for defining abstract data types.

Question 10.
Name any four operations on data structures.
Answer:
Traversing, Searching, Inserting, Deleting, Sorting, Merging (Write any four of them)

Question 11.
What do you mean by stack overflow and stack underflow?
Answer:
Stack overflow: If the stack is full and we try to add a new item into the stack means stack over flow.
Stack underflow: If the stack is empty and we try to delete an item from the stack makes the stack underflow.

Question 12.
Define the following terms:
(a) HTTPS
(b) Software ports
Answer:
(a) HTTPS (Hyper Text Transfer Protocol Secure): It is the technology used to protect data that are transferred from client to web server.

(b) Software port is used to connect a client computer to a server to access different types of services. For example HTTP, FTP, SMTP etc. Unique numbers are assigned to software ports to identify them.

Question 13.
Name any four attributes of <TD> tag.
Answer:
Align: Specifies horizontal alignment. Its value are left, right, centre or justify
Valign: Specifies vertical alignment. Its values are top, middle, bottom or baseline.
Bgcolor: Specifies border color for the cell.
Rowspan: Specifies the number of rows span for the cell.

Question 14.
Write the HTML code for the following :
(a) To create an email hyperlink to
dhsekerala@qmail.com
(b) To insert a video file video 1. mp4 in the webpage
Answer:
(a) <a href=mailto:” dhsekerala@qmail.com”
> DHSE</a>

(b) <embed src=”video1 .mp4″>

Question 15.
Write the names of the following :
(a) Operator used for adding two strings in Java Script.
(b) Function used in JavaScript to convert string type data containing numbers to number data type.
Answer:
(a) +
(b) Number()

Question 16.
Define the term data independence. What are the different levels of data independence?
Answer:
Data Independence is the ability to modify the scheme definition in one level without affecting the scheme definition at the next higher level. There are two types of data independence

• Physical Data Independence
• Logical Data Independence

Question 17.
Write any two advantages of parallel computing.
Answer:

• If one or more node fails, the entire system will not failed instead it works with reduced performance. This method is called fault tolerance.
• Sharing the computing power and storage resources with each other.

Question 18.
Write short note on cloud computing.
Answer:
It is an emerging computing technology. Here with the uses of Internet and central remote servers to maintain data and applications. Example for this is Email service, Office Software graphic software etc. The information is placed in a central remote server just like clouds in the sky hence the name cloud computing.

Answer any 9 questions from 19 to 29. Each carries 3 scores. (9 × 3 = 27)

Question 19.
Compare Arrays and Structures
Answer:

STRUCTURE	ARRAY
It is a user defined data type	It is a predefined data type
It is a collection of different types of logically related data under one name.	Collection of data elements of same data type having a common name.
Elements referenced using dot operator (.)	Elements reference using its subscripts (positive value)
When an element of a structure becomes another structure nested structure and complex structures are formed.	When an elements of another becomes another becomes array, multidimensional arrays are formed.
Structure contains array as its elements.	Array of structure can be formed.

Question 20.
Define the following OOP terms :
(a) Data Abstraction
(b) Inheritance
(c) Function overloading
Answer:
(a) Data Abstraction: It refers to the act of representing essential features without including the background details. Abstraction supports data hiding so that only the relevant information is expressed to the user and the rest of information remains hidden from the user.

(b) Inheritance: It is the capability of one class of things to inherit properties from another class. The class from which attributes are inherited is called the base class. The inherited class is called derived class.

(c) Function overloading: Functions with same name and different signatures (the number of parameters or data types is different)

Question 21.
Write short note on :
(a) Linked list
(b) Circular Queue
(c) Stack
Answer:
(a) Linked List: It follows dynamic data structure method. It grows and shrinks as and when the new items are added and removed respectively.

(b) Circular Queue: It is linear data structure in which the operations are performed based on FIFO principle and the last position is connected back to the first position.

(c) Stack: A stack is a linear structure in which items can be added or removed only at one end called top. Add an item into the stack is called push and deleting an item from the stack is called pop.

Question 22.
Differentiate client side scripting and server side scripting.
Answer:

Client Side Scripting	Server Side Scripting
Script is copied to client browser	Script is copied to the web browser
Executed by the client	Executed by the server and result is get back to the browser window.
Used for client level validation	Connect to the database in the server
It is possible to block by the user	It is not possible to block
Client side scripts depends the type and version of the browser.	It does not depefld the type and version of the browser.

Question 23.
Write the HTML code to display the following list:
1. Input devices
• Keyboard
• Mouse
• Scanner
2. Output devices
• Monitor
• Printer
Answer:

<HTML>
<BODY>
<OL>
<LI> Input devices</LI>
<ULTYPE=”disc”>
<LI> Keyboard </LI>

<LI> Mouse </LI>
<LI> Scanner </LI>
</UL>
<LI> Output devices </LI>
<ULTYPE=”disc”>
<LI> Monitor </LI>
<LI> Printer </LI>
<UL>
</OL>
</BODY>
</HTML>

Question 24.
Name the following :
(a) Built-in function used in JavaScript to get the character at a particular position in a string.
(b) Built-in function in JavaScript used to check whether a value is number or not
(c) Data type used in JavaScript for repre-senting true or false values.
Answer:
(a) charAt()
(b) isNaN()
(c) Boolean

Question 25.
Consider the following JavaScript code to find the sum of numbers upto a given limit.
Fill the blanks.
__________ sum Limit ()
{
_________ sum = 0, i, limit;
limit =
___________ (document, frmSum.txtLimit, );
___________ (i = 1 ; i <=limit; i++)
sum + = i;
docuemt. frmSum.txtSum __________ = sum;
}
Answer:
function sumLimit()
{
var sum=0, i, limit;
limit=Number(document.frmSum.txtLimit. Value):
Number (i=1 ;i<=limit;i++)
sum+=i;
document.frmSum.txtSum.Value = sum;
}

Question 26.
Briefly explain the following terms :
(a) Free hosting
(b) CMS
(c) Responsive web design
Answer:
(a) Free hosting: The name implies it is free of cost service and the expense is met by the advertisements. Some service providers allow limited facility such as limited storage space, do not allow multimedia files.

(b) CMS (Content Management System) is a collection of programs that is used to create, modify, update and publish websites contents.

(c) Responsive web design- The home page is displayed differently according to the screen size of the browser window we used. By responsive web design, companies have to design only one website that suitably displayed according to the screen size of the devices.

Question 27.
Briefly explain any three aggregate or column functions is SQL
Answer:

1. Sum() – find the total od a column
2. Avg() – find the average of a column
3. Min() – find the smallest value of a column

Question 28.
Write SQL queries for the following :
(a) To create a table with the following fields
Employee name
Designation
Basic pay
DA
Gross pay
(b) To display all employees whose Basic pay is more than 50,000
(c) To update .the DA of employees whose designation is manager to 20% of Basic pay.
Answer:
(a) CREATE TABLE
Employee (Employee_name
VARCHAR(70), Designation
VARCHAR(70), Basic_pay DEC(7,2),
DA DEC(7,2), Gross_pay DEC(7,2));

(b) SELECT *FROM Employee WHERE Basic_pay>50000;

(c) UPDATE Employee SET DA= Basic _pay*20/100 WHERE Designation =” Manager”;

Question 29.
Explain briefly about any three core data types in PHP.
Answer:
Integer – Two types -ve and +ve. PHP does not support unsigned integer data type. Eg: 8172,-22
Float/Double – Numbers with decimal point. Eg: 81.72, 7E-10, 123E12
String – Combination of characters enclosed in quotes. Eg: “BVM”, ‘HSS’ etc.

Answer any 2 questions from 30 to 32. Each carries 5 scores. (2 × 5 = 10)

Question 30.
(a) Write the basic structure of an HTML document (3)
(b) Write the HTML code for the following
(i) To display a scrolling text “welcome to my webpage” with 5 second delay in scrolling. (1)
(ii) To display the text H₂SO₄ (1)
Answer:
(a)

<HTML>
<HEAD>
<TITLE> Exampoint </TITLE>
</HEAD>
<BODY>
Body Section
</BODY>
</HTML>

(b) (i) <MARQUEE Scrolldelay=5000> welcome to my webpage</ MARQUEE>
(ii) H<SUB>2</ SUB> SO < SUB > 4</SUB>

Question 31.
(a) Define the following terms in RDBMS :
(i) Primary Key (2)
(ii) Attributes (3)
(b) Briefly explain any three operations in relational algebra
Answer:
(a) (i) Primary Key: It is a set of one or more attributes used to uniquely identify a row.
(ii) Attributes: Attributes means columns.

(b

1. Select Operation
2. Project Operation
3. Cartesian Product

Question 32.
(a) Define E-Govemance (2)
(b) W rite any four benefits of E-Govemance (3)
Answer:
(a) The integration of computers and communication technology for the benefit of government functions to the public is termed as E-Governance by this Govt, can serve the public in a convenient, efficient and transparent manner.

(b)

1. It enables automation of Govt, services.
2. It ensures the participation of citizens hence strengthen the democracy
3. It ensures more transparency hence eliminates corruption
4. It enhances responsibilities of various Govt. Departments’

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

Kerala Plus Two Zoology Question Paper March 2022 with Answers

A. Answer any three questions from 1 to 4. Each carries 1 score. (3 × 1 = 3)

Question 1.
Homologous organ: Divergent evolution:: Analogous organ:
Answer:
Convergent evolution

Question 2.
Expand the term ZlFT.
Answer:
Zygote Intra Fallopian Transfer

Question 3.
Mitotic division of zfgote results in the formation of blastomeres is called
Answer:
Cleavage

Question 4.
Name the enzyme that joins the DNA fragments in dis-contthuous strand during replication.
Answer:
DNA Ligase

B. Answer all questions from 5 to 6. Each carries 1 score.

Question 5.
The term ‘Biodiversity’ was popularised by the scientist ______
Answer:
Edward Wilson

Question 6.
The first antibiotic discovered was ______
Answer:
Penicillin

Part-II

A. Answer any two questions from 7 to 9. Each carries 2 scores.

Question 7.
‘Codon AUG is known as initiator codon.
(a) Name the amino acid coded by AUG.
(b) Write any two stop codons
Answer:
(a) Methionine
(b) U, UAG

Question 8.
Write the functions of the following
(a) Leydig cells
(b) Corpus luteum
Answer:
(a) Secrete testicular hormones called androgens or Testosterone.
(b) Secretes progesterone

Question 9.
Match the following:

(A)	(B)
i) Trtchoderma	a. Citric acid
ii) Monascus purpureus	b. Ethanol
iii) Saccharomyces cerevisiae	c. Cyclosponn A
iv) Aspergillus niger	d. Statin

Answer:

A	B
Trichoderma polysporum	a. Cyclosporin A
Monascus purpureus	b. Statin
Sacoharomyces cervisiae	c. Ethanol
Aspergillus niger	d. Citric acid

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

Question 10.
Choose the correct terms from the bracket to fill in the blanks and complete the table: (Bigbang theory, Miller’s experiment, Lamarkism, Darwinism)

(A)	(B)
i) Natural selection	a ____
ii) Chemical evolution	b ____
iii) Origin of Universe	c ____
iv) Use and Disuse of organs	d ____

Answer:

(A)	(B)
i) Natural selection	Darwinism
ii) Chemical evolution	Miller’s experiment
iii) Origin of Universe	Bigbang theory
iv) Use and Disuse of organs	Lamarkism

Question 11.
Write any four ill-effects of Drug/Alcohol abuse.
Answer:

1. Causes heart failure and hypertension.
2. Use of alcohol causes stomach ulcer and pancreatitis.
3. Causes lack of interest in personal hygiene,solation, depression , aggressiveness etc.
4. Causes deteriorating relationship with famil y and friends change in eating and sleeping habit etc.

Question 12.
(a) Name the cap-like structure present in sperm head.
(b) Write its function.
Answer:
(a) Acrosome

(b) Acrosome is filled with lytic enzyme that helps in the penetration of sperm in wall iayers of ovum  that leads to fertilisation

Question 13.
(a) Distinguish between Male heterogamety and Female heterogamey.
(b) Write one example for each.
Answer:

Male heterogamety	Female heterogamery
Here males are heterozygous (XY/XO)	Here females are heterozygous (ZW)
Mates produce two types of gamete	Females produce two types of gamete
Type of male gamete/sperm will determine the sex of the progeny	The type of female gamete/egg will determine the sex of the baby
This type of mechanism seen in	This type of mechanism seen in
. Human male	. Birds
. Grass hopper

(b) Male heterogamety – Different type of chromo some constitution in Male.
Eg :- Human or Drosophila
Female heterogamety -Different type of chromo some constitution in female
Eg :- Birds

Part – III

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

Question 14.
“Allele frequencies in a population are stable and is constant from generation to generation.”
(a) Name the principle
(b) Mention any four factors those affect this principle.
Answer:
(a) Hardy Weinberg Principle
(b) Gene flow mutation genetic recombination natural selection

Question 15.
“Sex of a child is determined by father”. Substantiate the statement.
(b) Name any four STDs.
Answer:
In human, the male produce two types of gametes i.e. one with X chromosome and other with Y chromosome. During fertilisation, Sperm with X chromosome fuses with egg to produce female child while sperm with Y chromosome fuses with eg to produce male child.

Question 16.
incidents of STDs are very high among the age group of 15-24 years.
(a) What is STD?
(b) Name any four STDs.
Answer:
(a) Sexually Transmitted Diseases
(b) Gonorrhoea, syphilis, genital herpes, hepatitis B,& AIDS

Question 17.
(a) Write four major causes of Biodiversity loss.
(b) Give one example for in-situ conservation and ex-situ conservation of Biodiversity.
Answer:
(a)

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

(b) In situ conservation
Eg :- Biosphere Reserves or National Park
Ex situ Conservation
Eg :- Botanical Gardens or Zoological Park

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

Question 18.
(a) Expand the term DNA. Who proposed double helical model of DNA?
(b) List out the nitrogen bases in DNA.
Answer:
(a) Deoxyribo Nucleic Acid James Watson & Francis Crick
(b) Adenine, Thyrnine, Guanine, Cytosine

Part – IV

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

Question 19.
(a) Expand thetermAlDS. Mention the name of virus that causes AIDS.
(b) Name the widely used diagnostic test for AIDS.
(c) List out any four practices for the prevention of AIDS.
Answer:
(a) Acquired Immuno Deficiency Syndrome

(b) ELISA Test

(c)

1. Use disposable syringe and needles.
2. Checking of blood before blood transfusion.
3. Use condom for male or female during intercourse.
4. Avoid intercourse with unknown partner.

Question 20.
Schematic diagram of a transcription unit is given below:

(a) Identify the pans A and B.
(b) What is transcription?
(c) Write the complementary DNA strand by observing the strand given below:
Answer:
(a) A – Promoter gene
B – Template strand

(b) It is the process of formation of mRNA from DNA

(c) 3 – TACGTACGTA-5

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

Kerala Plus Two Chemistry Previous Year Question Paper SAY 2019

Time: 2 Hours
Total Scores: 60

Questions Number 1-7 carry 1 Score each. Answer all the questions. (7 × 1 = 7)

Question 1.
The smallest repeating structural unit of a crystal is called
(a) Lattice point
(b) Bravais lattice
(c) Space lattice
(d) Unit cell
Answer:
(d) Unit cell

Question 2.
Which of the following is not a colligative property?
(a) Osmotic pressure
(b) Vapour pressure
(c) Elevation of boiling point
(d) Depression of freezing point
Answer:
(b) Vapour Pressure

Question 3.
The ion that is more effective for the coagulation of negatively charged As₂S₃ sol is
(a) Al³⁺
(b) \(\mathrm{PO}_4^{3-}\)
(c) \(\mathrm{SO}_4^{2-}\)
(d) Na⁺
Answer:
(a) Al³⁺

Question 4.
The role of NaCN in Froth flotation process involving an ore containing ZnS and PbS is as a ______________
Answer:
Depressant

Question 5.
The crystal field splitting energy for Octahedral (Δ₀) and Tetrahedral (Δ_t) complexes are related as
(a) Δ_t = \(\frac{3}{5}\) Δ₀
(b) Δ_t = \(\frac{5}{3}\) Δ₀
(c) Δ_t = \(\frac{4}{9}\) Δ₀
(d) Δ_t = \(\frac{9}{4}\) Δ₀
Answer:
(c) Δ_t = \(\frac{4}{9}\) Δ₀

Question 6.
The monomer of natural rubber is ______________
Answer:
Isoprene

Question 7.
Give an example for a Non-narcotic analgesic.
Answer:
Aspirin or Paracetamol

Questions number 8-20 carry 2 Scores each. Answer any 10 questions. (10 × 2 = 20)

Question 8.
In terms of band theory, what is the difference between a conductor and a semiconductor?
Answer:
In conductor, the valence band is partially filled and it overlaps with a high energy unoccupied conduction band. Electrons can easily flow under an applied electric field.
In semiconductors, the valence band is filled and there is a small gap between the valence band and the next higher conduction band. Some electrons can jump from the valence band to the conduction band and conduct electricity.
OR

In a conductor, the energy gap between the valence band & conduction band is very small, but in a semiconductor there is always a small energy gap between them.

Question 9.
How do galvanic cells differ from electrolytic cells?
Answer:
Galvanic cell: A device that converts chemical energy to electrical energy is known as an electrochemical cell or galvanic cell.
eg. Daniel cell.
Electrolytic cell: A device that converts electrical energy into chemical energy is known as an electrolytic cell.
eg. dry cell, lead storage cell.

Question 10.
Differentiate molecularity and order of a reaction.
Answer:

Order	Molecularity
1. It is the sum of the powers of the concentration terms in the rate law.	1. It is the no. of reacting molecules or atoms, or ions which collide simultaneously to bring about the reaction.
2. Experimentally determined.	2. Theoretical concept.
3. It can have whole no. fractional or zero values.	3. It can have only whole numbers. values other than zero.
4. Gives an idea about Mechanism.	4. No idea about mechanism.

Question 11.
Write the Arrhenius equation and identify the terms in it.
Answer:
K = \(A e^{-E a / R T}\)
or
log K = log A – \(\frac{E a}{R T}\)
or
\(\log \frac{K_2}{K_1}=\frac{E_a}{2.303 R}\left(\frac{1}{T_1}-\frac{1}{T_2}\right)\)
K – Rate constant
A – Arrhenius constant
E_a – Energy of Activation
T – Temperature
R – Universal Gas Constant
K₁ – Rate constant at temperature T₁
K₂ – Rate constant at temperature T₂

Question 12.
Write any two differences of physical absorption and chemical adsorption?
Answer:

Physisorption	Chemisorption
1. Due to Vander Waal’s forces.	1. Due to chemical bond formation.
2. Low temperature is favoured.	2. High temperature is favoured.
3. Not specific.	3. Highly specific.
4. Reversible.	4. Irreversible.

Question 13.
Match the following:

A	B
(i) Zinc	(a) Bauxite
(ii) Iron	(b) Malachite
(iii) Copper	(c) Calamine
(iv) Aluminum	(d) Magnetite
	(e) Galena

Answer:
Zinc – Calamine
Iron – Magnetite
Copper – Malachite
Aluminium – Bauxite

Question 14.
Write the main differences between the properties of white phosphorous and red phosphorous.
Answer:

White Phosphorous	Red Phosphorous
1. White waxy solid, poisonous.	1. Iron grey luster, non-poisonous, odourless.
2. Insoluble in water but soluble in CS2.	2. Insoluble in water and CS2.
3. Glows in dark.	3. Does not glow in the dark.
4. Less reactive.	4. More reactive.

Question 15.
Which element of the 3d series exhibits the largest number of oxidation states? Why?
Answer:
Manganese
Due to the completely half-filled electronic configuration. So it shows an oxidation state from +2 to +7.

Question 16.
What is Lanthanoid contraction? Give reason for it.
Answer:
The steady decrease in the size of atoms or ions of the lanthanides with increase in atomic number is called lanthanoid contraction. Along the lanthanoid series the nuclear charge increases by one unit and the new electron is added to the same inner subshell, namely 4f. The electrons in f orbital cannot effectively screen the nucleus.

Question 17.
Write the IUPAC name of the following:
(i) [Ni(CO)₄]
(ii) K₃[Fe(CN)₆]
Answer:
(i) [Ni(CO)₄] – Tetracarbonyl Nickel (O)
(ii) K₃[Fe(CN)₆] – Potassiumhexacyanoferrate (III)

Question 18.
Write the preparation of propan-2-ol from a Grignard reagent.
Answer:

Question 19.
Phenols are acidic. Why?
Answer:
Phenol forms phenoxide ion which is more stable due to delocalisation.

Question 20.
What are homopolymers and co-polymers? Give one example for each.
Answer:
Homopolymer – contains the same monomer units.
eg. Polythene, Teflon, PVC
Copolymer – Contains two or more different monomer units.
eg. nylon 6, 6, Buna – S

Questions Number 21-29 carry 3 Scores each. Answer any 7 questions. (7 × 3 = 21)

Question 21.
Aluminium crystallizes in a ccp structure and its metallic radius is 125 pm. Calculate the edge length of the unit cell and also find the number of unit cells in 1 cm³ of Aluminium.
Answer:
a = 2√2r
= 2√2 × 125
= 353 pm
Volume of unit cell = a³
a³ = (353 × 10-10 cm)³ = 4.44 × 10^-23
No. of unit cell in 1 cm³ = \(\frac{1}{4.44 \times 10^{-23}}\)

Question 22.
What is meant by positive and negative deviation from Raoult’s law and how is the sign of ΔmixH related to positive and negative deviation?
Answer:

Question 23.
What is an adsorption isotherm? Describe Freundlich adsorption isotherm.
Answer:
A graph drawn between the amount of gas adsorbed per gram of the adsorbent x/m and the pressure of the gas at constant temperature is known as an adsorption isotherm.
Frendlich adsorption isotherm
\(\frac{x}{m}=k p^{1 / n}\)
k – constant
n – integers
x & m – masses of adsorbate and adsorbent
\(\log \frac{x}{m}=\log k+\frac{1}{n} \log p\)

Question 24.
Explain how nitric acid is manufactured by Ostwald’s process?
Answer:
Ostwald Process
I. Ammonia is mixed with oxygen and is passed over platinum gauze catalyst at 500 K and 9 bar pressure

II. Oxidation of NO to NO₂: NO combines with excess O2 to form NO2 when the temp is lowered.
2NO + O₂ \(\rightleftharpoons\) 2NO₂
III. NO₂ is dissolved in water to form nitric acid
3NO₂ + H₂O → 2HNO₃ + NO

Question 25.
Explain S_N1 mechanism with suitable examples.
Answer:
Reaction of ter-butylbromide with alkali (OH)
Step I: Formation of a carbocation

Step II: Addition of Nucleophile

Question 26.
Write the reaction of ethyl bromide with the following reagents:
(a) aq. KOH
(b) KCN
(c) AgCN
Answer:
(a) CH₃ – CH₂Br + aq.KOH → CH₃CH₂OH
(b) CH₃ – CH₂Br + KCN → CH₃CH₂CN
(c) CH₃ – CH₂Br + AgCN → CH₃CH₂NC

Question 27.
Explain the reaction between primary, secondary, and tertiary amines with Hinsberg’s reagent.
Answer:
1. A primary amine reacts with Heisenberg’s reagent to form alkyl benzene sulphonamide which is soluble in alkali.

2. A secondary amine reacts with Hinsberg reagent to form dialkyl benzene sulphonamide, which is insoluble in alkali

3. A tertiary amine does not react with Hinsberg reagent.

Question 28.
Write any three differences of RNA and DNA.
Answer:

RNA	DNA
1. Contains Ribonucleic acid.	1. Deoxy ribonucleic acid.
2. Single stranded α-helical structure.	2. Double stranded α-helical structure.
3. Less stable.	3. More stable.
4. Contains bases such as uracil, cytosine, adenine, and guanine.	4. Contains bases such as Thymine, Cytosine, Adenine, and guanine.
5. Controls synthesis of proteins.	5. Controls the hereditary effect.

Question 29.
Write the therapeutic action of the following drugs:
(a) Antacids
(b) Disinfectants
(c) Antibiotics
Answer:
(a) Antacid: Substances which remove excess acid in the stomach are known as antacids.
(b) Disinfectants: Disinfectants are chemicals which kill microorganisms but are not safe to be applied to living tissues.
(c) Antibiotics: Antibiotics are chemical substances which, in low concentration, destroy or inhibit the growth of microorganisms by intervening in their metabolic process.

Questions Number 30-33 carry 4 Scores each. Answer any 3 questions. (3 × 4 = 12)

Question 30.
(a) Describe the Standard Hydrogen Electrode (SHE). (3)
(b) The emf of the cell obtained by coupling an electrode with SHE was 1.37 V. If SHE is the +ve electrode, find the potential of the given electrode. (1)
Answer:
(a) Standard Hydrogen electrode (SHE)
It consists of a Pt wire sealed into a glass tube carrying a platinum foil at one end. The electrode is placed in an aqueous acid solution containing 1 M H⁺ ions, pure hydrogen gas at 1 bar pressure is bubbled through the solution at 298 K. The electrode potential of SHE is taken as zero.

Question 31.
Draw the geometrical isomers of [PtCl₂(en)₂]²⁺. Which of the isomers are optically active? Give reason. (4)
Answer:

Cis isomer is optically active because it is unsymmetric and it forms a non-superimposable mirror image.

Question 32.
(a) What is Cumene? Explain the preparation of phenol from Cumene. (3)
(b) Identify the compound A. (1)

Answer:
(a) Cumene is isopropylbenzene

Question 33.
Describe the following with equations:
(a) Etard reaction. (2)
(b) Aldol condensation. (2)
Answer:
(a) Toluene reacts with chromyl chloride in carbon disulphide to give benzaldehyde.

(b) Aldol condensation

Aldehydes containing α hydrogen atom undergo aldol condensation in the presence of dil alkali to form β-hydroxy aldehyde or aldol.

Teachers recommend solving Kerala Syllabus Plus Two Zoology Previous Year Question Papers and Answers Pdf March 2024 to improve time management during exams.

Kerala Plus Two Zoology Question Paper March 2024 with Answers

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

Question 1.
Genes which code for a pair of contrasting traits are known as _____.
Answer:
Alleles

Question 2.
The process of copying genetic information from one strand of the DNA into RNA.
Answer:
Transcription

Question 3.
Name an. oral contraceptive for females developed by scientists at Central Drug Research Institute.
Answer:
Saheli

Question 4.
The enlarged end of penis called the glans penis is covered by a loose fold of skin called _____.
Answer:
Foreskin

Question 5.
Biodiversity is the term popularized by the sociobiologist to describe the combined diversity at all the levels of biological organization.
Answer:
Edward Wilson

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

Question 6.
Differentiate between analogous organs and homologous organs and mention one example each.
Answer:

Homologous organs	Analogous organs
. Organs that have similar structure but having differentfunction	. The organs that are having similar function but differ in structure and ongins are calLed analogous organs
. Homology indioetes common ancestry.	. Analogous organ represents the convergent evolution.
. Homologous organ represents the divergent evolution.
Examples:	Examples:
. Fore limbs of whale, bat, human and cheetah.	. Wings of Butterfly and Birds.
. Hearts of Vertebrates	. Eye of Octopus and Mammals.
. Brain of Vertebrates	. Fhppers of Penguins and Dolphins
. Tendril in Cucurbits & Thom in Bougainvillea	. Tuber of Potato and Sweet Potato.

Question 7.
Observe the given diagram of male reproductive system, and identify the parts labelled as A, B, C and D.

Answer:
A – Vas deferens
B – Urethra
C – Epididymis
D – Rete testis

Question 8.
Infections or diseases which are transmitted through sexual intercourse are collectively called sexually transmitted infections.
(a) NameanytwoSTis.
(b) Suggest any two methods to prevent STIs.
Answer:
(a) Gonorrhoea
• Syphilis

(b) • Avoid sex with unknown partners
• Always use condoms during coitus.

Question 9.
Complete the following table:

Chromosomal Disorder	Karyotype	Symptoms
(A) _______	Trisomy 21	Palm is broad, Short statued
(B) _______	(C)  _______	Gynaecomastia
Turner’s Syndrome	44 + Xo	D

Answer:
A – Down’s Syndrome
B – Kllnefelter’s Syndrome
C – 47 with XXY / 44A + XXY
D – Sterile female

Question 10.
Innate immunity is non-specific type of defence, that is present at the time of birth. Which are the four types of barriers involved in innate immunity and mention one example for each.
Answer:

1. Physical Barriers
   • It includes’ the anatomical barriers like skin.
2. Physiological Barder
   • It indude body temperature Cellular Barriers
   • Phagocytic cells in our bod y such as Polymorpho-nuclear leucocytes (PMNLe neutrophils)
3. Cytokine Barriers
   • Interferons. (My one example in each)

Question 11.
Complete the following flow chart which shows the origin and evolution of man.

Answer:
A – Ram apithecus
B – Homo habilis
C – Homo erectus
D – Homo sapiens

Question 12.
A wide range of contraceptive methods are presently available.
(a) Name two surgKal methods advised for male and female partner as a terminal method to prevent any more pregnancies. (1)
(b) Give two examples for copper releasing IUDS. (1)
Answer:
(a) Male – Vasectomy.
Female – Tubectomy.
(b) CuT, Cu7 and Multiload 375 (Any two exam pies)

Question 13.
In a cross between true breeding red-flowered (RR) and true breeding white-flowered (rr) plants, the F₁ (Rr) was pink coloured.
(a) Name the inheritance pattern mentioned here. (1,4)
(b) F₁ was self-pollinated and F₂ was obtained. What is the genotypic ratio and phenotypic ratio of F₂. (1)
(c) Mention a plant which shows this inheritance. (1/2)
Answer:
(a) Incomplete dom inanc
(b) Phenotypic ratio = 1 : 2 : 1
Genotypic ratio = 1 : 2 : 1
(c) Dog flower plant or Snapdragon or Antirrhinum

Question 14.
The following diagram shows central dogma in molecular biology. Write the name of process represented asAand B.

Answer:
A – Transcription
B – Translation

Question 15.
Match the following:

A	B
Clostridium butylicum	Acetic acid
Aspergillus niger	Lactic acid
Acetobacter aceti	Butyric acid
Lactobacillus	Citric acid

Answer:

A	B
Clostridium butylicum	Butyric acid
Aspergillus niger	Citric acid
Acetobacier aceti	Acetic acid
Lactobacillus	Lactic acid

Question 16.
In a debate conducted in school, your friend said that AIDS can be transmitted through touch or physical contact.
(a) Do you agree with that statement? (1/2)
(b) Name theeclinical test used to diagnose AIDS. (1/2)
(c) How do HIV infect human body? (1)
Answer:
(a) No.

(b) ELISA- Enzyme Linked Immuno-Sorbent Assay.

(c)

1. HIV enters body and infect the Macrophages
2. RNA genome replicates to form viral DNA by Reverse transcriptase.
3. Viral DNA incorporates into host cell’s DNA.
4. Infected cells produce more and more viral particles.
5. Enters Helper T Lymphocytes (TH).
6. Replicates and produce progeny virus.
7. Attack other T cells so that T cells count decreases.
8. Immunity weakens.

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

Question 17.
Observe the diagrammatic presentation of various events during a menstrual cycle.

(a) Identify ‘A’ and ‘B’ in graph. (1)
(b) Name two different methods of biodiversity conservation. (1)
(c) What is so special about tropics that might account for their greater biological diversity? (1)
Answer:
(a) A – Estrogen; B – Progesterone.

(b) C – Corpus luteum. It secretes a large amount of progesterone, which maintain the endometrium of uterus.

(c) Luteinizing hormone.

Question 18.
Pedigree analysis of two Mendelian disorders are shown below:
Answer:

1. Isolation of DNA
2. Digestion of DNA by restriction endonuclease enzyme
3. Separation of DNA fragments by electrophoresis
4. Blotting of separated DNA fragments into synthetic nylon or nitrocellulose membrane.
5. Hybridisation using labelled VNTR (Variable Number of Tandem Repeats) pcobe.
6. Detection of hybridised DNA fragment by autoradÍography.

Question 19.
Answer:
(a)

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

(b) In Situ Conservat ion – Ex Situ Conservation

1. Speciation is generally a function of time.
2. Tropical latitudes have remained relatively undisturbed for millions of years and thus had a long evolutionary time for species diversification.

Question 20.
Pedigree analysis of two Mendelian disorders are shown below:

(a) Identify the trait represented asAand B.(1)
(b) Which is the symbol for consanguineous mating used in pedigree analysis? (1)
(c) What do you mean by pedigree analysis?(1)
Answer:
(a) A – Autosomal dominant trait/ Myotonic dystrophy
B – Autosomal recessive trait I Sickle cell anaemia

(b)

(c) Analysis of a genetic trait in a several generations of a family is called pedigree analysis.

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

Kerala Plus Two Zoology Question Paper March 2023 with Answers

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

Question 1.
Select the odd one. Justify your selection. (Rete testis, Vasa efferentia, Fallopian tube, Vas deferens)
Answer:
Fallopian tube.

Question 2.
Write the Central dogma in Molecular biology.
Answer:
Genetic information flows from DNA-» mRNA —» Protein

Question 3.
Which microbe is called baker’s yeast?
(A) Propionibacterium sharmanii
(B) Lacto bacillus
(C) Saccharomyces cerevisiae
(D) Aspergillus niger
Answer:
Saccharomyces cerevisiae

Question 4.
Pick out the correct pair of disease and its pathogen:
(A) Filaria – Rhino virus
(B) Typhoid – Streptococcus
(C) Malaria – Plasmodium
(D) Ascariasis – Entamoeba
Answer:
Malaria-Plasmodium.

Question 5.
Identify two ex-situ conservation approaches of or-ganisms from the following list:(Zoological Park, Biosphere Reserve, National Park, Botanical Garden)
Answer:
Zoological Park, Botanical Garden.

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

Question 6.
Placenta also act as an endocrine tissue and produce several hormones.
(A) Name any two placental hormones.
(B) Write two functions of Placenta, (other than endocrine function)
Answer:
(A) 1. Human chorionic gonadotropin
2. Human placental lactogen

(B) It facilitates the supply of oxygen and nutrients to the embryo.
• It helps to remove CO₂ and excretory wastes produced by the embryo.

Question 7.
The graph given below shows the ovarian events and ovarian hormone levels during menstrual cycle

(i) Name hormones A and B.
(ii) Write the ovarian events during luteal phase.
Answer:
(i) A-Progesterone
B – Estrogen.

(ii) The remaining parts of the Graafian follicle transform as the corpus luteum.
• It secretes large amounts of progesterone essential for maintenance of endometrium.

Question 8.
What are lUDs? Name one copper releasing and one hormone releasing lUDs.
Answer:
lUD’s (Intra Uterine Devices) :-These devices that are inserted by doctor or expert nurse into the uterus through vagina.

• Copper releasing lUDs .
Eg CuT, Cu7 & Multiload 375

• Hormone releasing lUDs.
Eg Progestasert, LNG -20 (Any one example in each)

Question 9.
Match the following:

Genetic Disorders	Genetic Reasons
Klinefelter’s syndrome	21st Trisomy
Down’s syndrome	Lack of one ‘X’ chromosome in females(XO)
Turner’s syndrome	Due to autosomal recessive trait
Phenylketonuria	Presence of an extra X chromosome in males (XXY)

Answer:

Genetic Disorders	Genetic Reasons
Klinefelter’s Syndrome	Presence of an extra X chromosome in males (XXY)
Down’s Syndrome	21st Trisomy.
Turner’s Syndrome	Lack of one ‘X’ chromosome in female (XO).
Phenylketonuria	Due to autosomal recessive trait.

(i) A-Terminator gene B – Coding strand
(ii) It determines the base sequence in mRNA

Question 10.
Schematic representation of a transcription unit is given;

(i) Fill up the missing parts A and B.
(ii) Write the role of template strand in transcription.
Answer:
(A) The organs that are having similar function but differ in structure and origins.
(B) Eyes of octopus and mammals, Wings of butterfly and birds

Question 11.
(A) Define Analogous organs.
(B) Identify analogous organs from the given ex-amples :
(i) Eyes of octopus and mammals
(ii) Vertebrate hearts
(iii) Wings of butterfly and bird
(iv) Forelimbs of Cheetah and Human
Answer:
(A) The organs that are having similar function but differ in structure and origins.
(B) Eyes of octopus and mammals, Wings of butterfly and birds

Question 12.
Using the given terms in brackets, complete the following evolutionary stages of man :
(Homo sapiens, Homo habilis, Homo erectus, Australopithecines)

A – Australopithecines
B – Homo habilis
C- Homo erectus
D – Homo sapiens

Question 13.
Differentiate between Active immunity and Passive immunity.
Answer:

• Active Immunity
  1. Antibodies are produced in the host body when pathogen is entered into body.
  2. It shows the property of memory.
• Passive Immunity
  1. Ready-made anti-bodies are directly injected into the body.
  2. Memory property is absent.

Question 14.

Write some important measures that would be use-ful for the prevention and control of alcohol and drug abuse among adolescents.(Write relevant four points)
Answer:

1. Avoid undue pressure in adolescence
2. Proper education and counselling
3. Providing help from parents
4. Peer group looking for the danger sign

Question 15.
Two bioactive molecules are given :
(i) Cyclosporin-A
(ii) Streptokinase
(A) Name the microbe,which produces these bioactive molecules.
(B) Write its use.
Answer:
(A) Trichoderma polysporum. Used as Immunosuppressive agent.
(B) Streptococcus. Used as clot buster (Removing the clot)

Question 16.
A figure showing the global biodiversity of inverte-brates and vertebrates are given.

(A) Identify the most diverse groups of vertebrates and invertebrates.
(B) What are the three important levels of biodiversity?
Answer:
(A) Vertebrates – Fishes Invertebrates – Insects
(B) Genetic Diversity, Species diversity, Ecological diversity

III. Answer any 3 questions from 17 to 20. Each

Question 17.
(A) What are STIs?
(B) Give two examples!
(C) Write any two preventive measures of STIs.
Answer:
(A) Sexually Transmitted Infections
(B) Gonorrhoea and Syphilis.
(C) Avoid sex with unknown partners. Always use condoms during coitus.

Question 18.
Cross between Red flower (RR) and white flower (rr) bearing plants of Snapdragon produced all plants with pink flowers in F₁ generation.
(A) Name the genetic phenomenon of this cross.
(B) Illustrate F2 generation of this cross using Punnet square.
Answer:
(A) Incomplete Dominance
(b)

Question 19.
The given illustration shows ‘Evil Quartet’ of biodiversity loss :

(i) Fill up A’ and ‘B.
(ii) Explain Co-extinction and Alien species invasion with suitable examples.
Answer:
(i) A-Habitat loss and fragmentation B – Over-exploitation.

(ii) Co-extinction – When a species becomes extinct, the plant and animal species associated with it also become extinct.
Eg plant and its pollinator, Host and its parasites.

Alien species invasion – New species introducing into a geographical region is called alien species. It cause decline or extinction of indigenous species.

Eg : – Nile Perch introduced into Lake Victoria in East Africa lead to extinction of Cichlid fish in the lake.

Question 20.
Explain the transformation experiments performed by Frederick Griffith with bacteria Streptococcus
Pneumoniae.
Answer:
Streptococcus pneumonia bacterium has two strains S strain cause Pneumonia. R strain did not cause Pneumonia.

Steps in Griffith’s experiment

S-strain Injected into mouse → Mouse dies of pneumonia.

R-strain → Injected into mouse → Mouse lives Heat killed S-strain → Injected into mouse → Mouse lives.
Heat killed S-strain + Live R-strain → Injected into mouse Mouse → dies

Griffith’s postulated that some ‘transforming principle’ transferred from the heat- killed S-strain to R-strain and make them virulent.