Kerala Syllabus Class 8 Basic Science Model Question Paper Set 4

To reduce exam fear, Class 8 Basic Science Question Paper Kerala Syllabus Set 4 provide good practice.

Kerala Syllabus 8th Standard Basic Science Model Question Paper Set 4

Time: 2 hour
Total score:60

Instructions:

1. The first 15 minutes is cool-off time. This time is meant for reading the questions and planning your answers.
2. This question paper includes 10 questions in sections A, B and C
3. You need to answer only one of the options provided for each of the choice-based questions.

PHYSICS

Time: 40 minutes
Total Score: 20

Section – A

Select the correct answer for questions 1 to 2. Answer all questions. (1 score for each question) (2 × 1 = 2)

Question 1.
The figure shows the lines of force between the poles of two bar magnets. Identify the poles represented by A and B.

a) A-North, B-South
b) A-South, B-South
c) A -North, B -North
d) A -South, B -North
Answer:
c) A -North, B -North

Question 2.
Two statement are given below. Examine them and choose the correct answer.
Statement 1: Charging by conduction is the method of charging an object by direct physical contact with a charged object.
Statement 2: Charging by induction is the method of charging an object with direct physical contact of a charged object.
Options:
a) Both statements are correct
b) Only the second statement is correct
c) Only the first statement is correct
d) Both statements are incorrect
Answer:
c) Only the first statement is correct

Section- B

Answer questions 3 to 8 in more than one sentence. Questions 7 and 8 have choices. (2 score for each question) (6 × 2 = 12)

Question 3.
Write down two precautions to be taken for protecting ourselves from lightning.
Answer:
• Do not operate electrical equipment’s.
• Avoid touching metal objects.
• Do not seek shelter under tall or isolated trees. (any two)

Question 4.
Classify the following situations into contact and non-contact forces.
a) Applying break in a bicycle.
b) The earth revolving around the sun.
Answer:
Contact force
a) Applying brake in a bicycle Non-Contact force
b) The earth revolving around the sun

Question 5.
Two identical balloons one filled with water and other with kerosene of equal quantity.
iMG- 1
a) Identify the balloon filled with water.
b) Why is the expansion of balloons appearing to be different in figures (a) and (b)?
Answer:
a) Figure (b)
b) Water has higher density than kerosene. As density increases, liquid pressure increases. So the balloon which is expanded has water filled in it and the other balloon which is small in size has kerosene filled in it.

Question 6.
Lightning conductors are fixed to protect tall buildings from the danger of lightning. Write down how lightning conductors work?
Answer:
A lightning conductor has sharp pointed ends where 9. the electric charge density is highest. It is connected to the earth through a conducting wire, allowing charges to safely flow into the ground. When clouds accumulate a large negative charge, positive charges are induced at the pointed ends of the conductor, which neutralizes the cloud’s charge. If the clouds carry a positive charge, negative charges gather at the pointed ends which neutralizes the cloud’s charge. When lightning occurs charge accumulate at the pointed ends and reaches to earth through the conducting wire. Thus the object or building is protected.

Question 7.
A. Classify the physical quantities given in the box as fundamental quantities and derived quantities.
Length, density, area, mass

Fundamental quantities	Derived quantities

Answer:

Fundamental quantities	Derived quantities
Length, Mass	Density, Area

B. 1 mm is the least count of a metre scale.
a) What do you mean by least count?
b) Arrange the following units in ascending order of their values.
(mm, km, nm. cm)
Answer:
a) The smallest value that can be measured using
an instrument is called its least count.
b) nm < μm < cm < km

Question 8.
A. What would be the radius of curvature of a concave mirror with a focal length of 40 cm?
Answer:
f = 40 cm
f = \(\frac{R}{2}\)
R = f × 2
R = 40 × 2 = 80 cm

OR
B. a) Copy the ray diagram and complete it showing the image formation.

Answer:

b) What are the characteristics of the image formed?
Answer:
Real, inverted and enlarged

Section – C

Questions 9 to 10 carry 3 score each. Question 10 has a choice. (2 × 3 = 6)

Question 9.
Write your inferences.
a) All magnets have same shape.
b) All magnets show N, S direction when suspended freely.
c) All magnets are man made.
Answer:
a) There are different types of magnets.

b) Yes. Because the north pole of magnet turns to geographical south of earth and south pole turns to geographical north of earth.(or Earth acts like a large magnet. Hence the poles of the suspended magnet is opposite to the poles of the earth’s magnet.)

c) No, There are natural and man made magnets.

Question 10.
A. Convert the following units into SI units without changing their values.
a) 3500g
b) 2.5 km
c) 2h
Answer:
a) 3500g = \(\frac{3500}{1000}\) kg = 3.5 kg

b) 2.5km = 2.5 × 1000 m = 2500 m

c) 2h = 2 × 60 × 60s = 7200s.

OR
B. State whether the following symbol are right or wrong. Correct them if wrong.
a) m/s/s
b) 50 kg/m3
c) 100 n
d) 20 kgs
e) 3M
Answer:
a) Wrong. m/s² is the correct form.
b) Right
c) Wrong. 100 N is the correct form.
d) Wrong. 20 kg is the correct form.
e) Wrong. 3 m is the correct form.
f) Wron 1.5 kg or 1500 g is the correct form.

CHEMISTRY

Time: 40 minutes
Total Score: 20

Section – A

Answer all the questions from 1 to 2.1 score for each.

Question 1.
Match the Following

Reaction/Property	Product Basis
i) Acid reacts with a highly reactive metal	a) CO2 gas
ii) Acids react with carbonates	b) H+ ions
iii) Basis of general properties of acids	c) H2 gas
iv) Non-metal oxide reacts with water	d) Acidic properties

A) i – a, ii – c, iii – b, iv – d
B) i – c, ii – a, iii – d, iv – b
C) i – c, ii – a, iii – b, iv – d
D) i – d, ii – b, iii – a, iv – c
Answer:

Reaction/Property	Product Basis
i) Acid reacts with a highly reactive metal	c) H2 gas
ii) Acids react with carbonates	a) CO2 gas
iii) Basis of general properties of acids	b) H+ ions
iv) Non-metal oxide reacts with water	d) Acidic properties

Question 2.
Two statements are given below.
(i) Gold can be coated on a copper bangle by the process of electroplating.
(ii) In this process, the copper bangle is connected to the positive terminal of the battery. Choose the correct one from the options given below.
A. Both the statements (i) and (ii) are incorrect.
B. Statement (i) is correct. However, the statement (ii) is incorrect.
C. Both statements (i) and (ii) are correct.
D. Statement (ii) is correct. However, statement (i) is incorrect.
Answer:
B. Statement (i) is correct. However, the statement (ii) is incorrect.

Section – B

Two questions from 3 to 8 have choices. Each question carries 2 scores. (6 × 2 = 12)

Question 3.
Sodium reacts with Water to form sodium hydroxide and hydrogen gas. Is this a physical change or a chemical change? Why
Answer:
it is a chemical change because new substances are formed.

Question 4.
A) Give a reason for the following:
a) More than 65% of the body of living organisms is made up of water.
b) Ice formed on freezing water floats on it.
Answer:
a) Water has a high specific heat capacity, so it prevents sudden changes in body tempera-ture. This helps plants and animals maintain a stable internal environment and survive in dif-ferent climatic conditions.

b) When water freezes into ice, its volume in¬creases and density decreases. So, ice floats on water.

B. Water expands when it freezes.
a) What change happens to its volume and density?
b) How does this property help aquatic life in cold regions?
Answer:
a) When water freezes, its volume increases and its density decreases. This is why ice is lighter than water and floats on its surface.

b) Ice floats on water because its volume increases (density decreases) when it freezes. Floating ice acts as a protective layer (insulator). This insulation prevents the water below from freezing. This allows fish and aquatic life to survive in cold regions.

Question 5.
a) The symbol for the element hydrogen is H. What is the difference between 2H and H₂?
b) Classify the following into elements and compounds and list them.
[Carbon, Carbon dioxide, Oxygen, Sodium chloride]
Answer:
a) In a 2H refers the two atoms of Hydrogen. H₂ refers to a Hydrogen molecule formed by two atoms.

b)

Elements	Compounds
Carbon	Carbon dioxide
Oxygen	Sodium Chloride

Question 6.
a) How is soda water made?
b) Write the chemical equation for this reaction
Answer:
a) Soda water is made by dissolving carbon dioxide in water under high pressure.
b) CO₂ + H₂O → H₂CO₃

Question 7.
The degree of acidic/basic nature of soil and other substances is determined by calculating their pH value.
a) Who invented the pH scale?
b) What characteristic pH value defines a neutral solution?
Answer:
a) The pH scale was invented by the Danish scientist Sorensen.
b) The characteristic pH value that defines a neutral solution is 7.

Question 8.
A. a) What is the natural source from which natural rubber is obtained?
b) Explain why synthetic rubbers are predominantly used in the manufacture of tyres?
Answer:
a) Natural rubber is obtained from the latex collected from the rubber tree.

b) Synthetic rubber shows less wear and tear compared to natural rubber. That is why synthetic rubbers are used in tyre manufacture.

OR
B. a) What is the difference between thermoplastics and thermosets?
b) Which of the following is a natural polymer?
[Polythene, Nylon, Bakelite, Cellulose]
Answer:
a) Thermoplastics: Soften on heating and can be reshaped many times.
Thermosets: Harden permanently on heating and cannot be remoulded once set.
b) Cellulose.

Section – C

One question from 9 to 10 has a choice. Each question carries 3 scores. (2 × 3 = 6)

Question 9.
One molecule of nitric acid contains one hydrogen atom, one nitrogen atom and three oxygen atoms.
a) Write the chemical formula of nitric acid
b) Find the total number of atoms present in four molecules of nitric acid.
c) How many ammonia (NH3) molecules are required to obtain the same number of atoms present in four molecules of nitric acid?
Answer:
a) HNO₃

b) H = 1
N = 1
O = 3
Total = 1 + 1 + 3 = 5 atoms
For four molecules:
4 × 5 = 20 atoms

c) Atoms in one NH, molecule:
N = 1
H = 3
Total = 4 atoms
Number of ammonia molecules
= 20 ÷ 4 = 5 molecules

Question 10.
A. The stomach produces hydrochloric acid (HCl) for digestion. Excess acid can cause problems, which
are treated with medicines called antacids.
a) Define the term Neutralisation reaction?
b) What is the chemical nature of antacids (acidic or basic)?
c) Write the name of a commonly used antacid?
Answer:
a) The chemical reaction in which an acid and a base react to form water and a salt is known as a neutralisation reaction. Magnesium hydroxide, also known as milk of magnesia

b) Basic

c) Magnesium hydroxide, also known as milk of magnesia

OR
B. Take a pinch of ammonium sulphate in a test tube and mix it well with some water. Pour barium chloride solution into it. A white curdy precipitate is formed.
a) Identify the substance that forms the curdy white precipitate.
b) Write the balanced chemical equation for the reaction between ammonium sulphate ((NH₄)2SO₄) and barium chloride (BaCl).
c) What property of the precipitate is demonstrated when it is observed that adding dilute hydrochloric acid (HCl) causes no change?
Answer:
a) Barium sulphate (BaSO₄)

b) (NH₄)₂ + SO₄ + BaCl₂ → BaSO₄ + 2NH₄Cl

c) Barium sulphate is insoluble in dilute hydrochloric acid.

BIOLOGY

Time: 40 minutes
Total Score: 20

Section – A

Choices are given for questions 7, 8,10. Answer questions 1 and 2. Each question carries 1 score. (2 × 1 = 2)

Question 1.
Which of the following statements is correct regarding electron microscopes?
(A) It helps in seeing up to a thousand times larger.
(B) It helps in detailed observation of living cells, viruses and molecular structures.
(C) It uses an electron beam.
(D) It uses light.
Answer:
(B) and (C)

Question 2.
Choose and write the correct answer from the options given below where the pairs are correctly matched:

Meiosis	Period of intense mental and emotional changes
Adolescence	Fully matured ovum is released from the ovary
Cell plate	Chromosome number is reduced to half
Ovulation	Cytokinesis in plant cell

(a) A-I, B-II, C-III. D-IV
(b) A-II, B-III, C-IV, D-I
(c) A-III, B-I, C-IV, D-II
(d) A-III, B-IV, C-II, D-I
Answer:
(c) A-III, B-I, C-IV, D-II

Section – B

Write answers to questions 3 to 8. Each question carries 2 score. (6 × 2 = 12)

Question 3.
Which pair is correct?
a) Online system – Disease and pest information collection, solution – Up-to-date knowledge about climate change – Market opportunities
b) Family members – financial assistance to farmers, procurement, marketing
c) Local Government Institutions – Financial Assistance, Employment Assistance, Psychological Support.
d) Cooperative societies – Use of barren lands – Approval – Government assistance
e) Krishi Bhavan – Distribution of best planting materials – Scientific guidance and training programs for agriculture
Answer:
a) Online system – Disease and pest information collection, solution – Up-to-date knowledge about climate change – Market opportunities

e) Krishi Bhavan – Distribution of best planting materials – Scientific guidance and training programs for agriculture

Question 4.
Analyse the statements given below and give reasons for each.
a) One of the most important ecological hotspots in India is the Western Ghats.
b) Sacred groves are to be protected and maintained.
Answer:
(a) The Western Ghats is designated as one of the world’s most important ecological hotspots primarily for twp key reasons: high endemicity and significant habitat loss.

Sacred groves are patches of forest or natural vegetation protected and revered by local 8 communities on religious and cultural grounds. Their protection is vital for both biodiversity conservation and cultural heritage.

Question 5.
Complete the table.

Division	Characteristics
Carnivora	____(A)____
____(B)____	Have retractable claws and excellent night vision.
Panthera	____(C)____
Panthera tigris	____(D)____

Answer:
(A) Sharp teeth and claws adapted for hunting and eating meat.
(B) Felidae
(C) Ability to roar, large and powerful body structure.
(D) Orange fur with black stripes and strong large body.

Question 6.
Observe the illustration and answer the questions below.

(a) Which process does the illustration indicate?
(b) Explain the process that the illustration indicates.
Answer:
a) Formation of organelles found in cells.

b) Eukaryotic cell engulfs small aerobic bacteria.
Instead of digesting the small cell, it protects it. Gradually, these become mitochondria. Eukaryotic cell engulfs small photosynthetic bacteria Instead of digesting the photosynthetic bacteria, it protects it. Gradually these become chloroplasts.

Question 7.
A. Complete the flowchart:

Answer:
A – Anther
B – Filament
C – Style
D – Ovary

B. Observe the given figure and answer the following questions:

a) Identify A and B in the given figure.
b) Give an example each for A and B which shows this type of reproduction.
Answer:
a) A- Binary fission, B – Multiple fission
b) Binary fission is seen in Bacteria and amoeba. Multiple fission is seen in Plasmodium.

Question 8.
A. Obsere the picture and answer the questions below.

a) Which organelle is represented by the picture?
b) What is the function of this organelle?
Answer:
a) Endoplasmic Reticulum
b) These organelles appear as a network of tubules within the cell, serve as pathways for conducting materials. It helps in the synthesis and removal of materials required by the cell.

OR
B. Choose the answer to the statements given below from the box and write it down.

Muscle tissue, Connective tissue, Epithelial tissue, Neural tissue

a) Connects different parts of the body.
b) Controls and coordinates bodily functions.
Answer:
a) Connective tissue
b) Neural tissue

Section – C

Answer questions 9 and 10. Each question carries 3 score. (2 × 3 = 6)

Question 9.
The names of Papaya in different regions are given below:
Papaya, Karumusa, Kappalanga
a) How can a person from a different region identify this plant?
b) What is the solution to this problem?
Answer:
a) A person can identify this plant in different regions using its scientific name. Since scientific names are the same worldwide, it helps to avoid the confusion caused by different local names.

b) The solution to this problem is to use the Binomial Nomenclature system. This system gives each organism a unique and universally accepted name. This makes identification clear and unifonn everywhere.

Question 10.
A. Gene banks are an Ex-situ conservation method.
a) What is the role of gene banks in the conservation of biodiversity?
b) What are the various levels of Biodiversity?
c) Write the names of Ecological hotspots in India?
Answer:
a) These are research centres with facilities to collect seeds and gametes to preserve them for a long time. Organisms can be recreated out of them whenever required.
b) Ecosystem biodiversity, Species diversity, Genetic diversity.
c) Western Ghats, North-Eastern Himalayas, Indo- Bumia region

B. Logo of an international organisation is given.

a) Write the name of this organisation.
b) What is the obj ective of this organisation?
c) Write two instructions that can be included in the poster to create awareness in people of your locality to protect the environment.
Answer:
a) WWF

b) To understand the importance of biodiversity, i.e,, Conserving Biodiversity, Sustainable Resource Use, and Reducing Human Impact are the major objectives.

c) • Native plants support local pollinators (bees, butterflies) and require less water and maintenance than non-native species, helping conserve water and local biodiversity.

• Carry a reusable water bottle and shopping bag. Local water bodies and parks are often clogged with single-use plastic, harming wildlife and degrading our nature’s beauty.