CBSE Class 10 Science 2020 — Set 2

Questions in this 2020 Science paper (Set 2)

All 30 questions from this set, exactly as asked. Try each one, then open the question-paper PDF above for the complete paper.

1. 1.
   Covalent compounds have low melting and boiling point. Why?
2. 2.
   How many metals are present in second period of periodic table?
3. 3 (a).
   Read the passage on geothermal energy and answer: Geothermal energy is the energy produced by the heat of molten rocks formed in the deeper hot regions of the earth … (a) What are geothermal energy hot-spots?
4. 3 (b).
   (Based on geothermal energy passage) (b) Name two countries, other than India, where power plants based on geothermal energy are operational.
5. 3 (c).
   (Based on geothermal energy passage) (c) Name the phenomenon that explains the working of an electric generator.
6. 3 (d).
   (Based on geothermal energy passage) (d) State an important advantage of using AC over DC.
7. 4 (a).
   Read the passage on thyroid gland and answer: Thyroid gland is a bilobed structure situated in our neck region. It secretes a hormone called thyroxine. Iodine is necessary for the thyroid gland to make thyroxine. Thyroxine regulates carbohydrate, protein and fat metabolism in the body. It promotes growth of body tissues also. When there is an excess of thyroxine in the body, a person suffers…
8. 4 (b).
   (Based on thyroid gland passage) (b) State the function of thyroxine in human body.
9. 4 (c).
   (Based on thyroid gland passage) (c) What is hyperthyroidism?
10. 4 (d).
    (Based on thyroid gland passage) (d) How can we control hypothyroidism?
11. 5.
    Consider the following reasons for the reddish appearance of the sun at the sunrise or the sunset: A. Light from the sun near the horizon passes through thinner layers of air. B. Light from the sun covers larger distance of the earth's atmosphere before reaching our eyes. C. Near the horizon, most of the blue light and shorter wavelengths are scattered away by the particles. D. Light from the…
12. 6.
    The maximum resistance which can be made using four resistors each of 2 Ω is:

    • (a) 2 Ω
    • (b) 4 Ω
    • (c) 8 Ω
    • (d) 16 Ω
13. 7.
    A student plots V-I graphs for three samples of nichrome wire with resistances R₁, R₂ and R₃. Choose from the following the statement that holds true for this graph. (In the graph, R₃ has the steepest slope, R₁ is in the middle, and R₂ has the least slope, with I on the y-axis and V on the x-axis)

    • (a) R₁ = R₂ = R₃
    • (b) R₁ > R₂ > R₃
    • (c) R₃ > R₂ > R₁
    • (d) R₂ > R₁ > R₃
14. 8.
    Which of the following are water intensive crops?

    • (a) Wheat and rice
    • (b) Wheat and sugarcane
    • (c) Sugarcane and rice
    • (d) Wheat and gram
15. 9.
    Bandharas and Tals are age old water harvesting concepts / structures found in:

    • (a) Bihar
    • (b) Maharashtra
    • (c) Tamil Nadu
    • (d) Rajasthan
16. 10.
    Identify 'x', 'y' and 'z' in the following reaction: 2 KClO₃(x) —(y)→ 2 KCl(x) + O₂(z)

    • (a) x = gas; y = reaction condition; z = gas
    • (b) x = solid; y = liquid; z = gas
    • (c) x = number of moles of KClO₃; y = reaction condition; z = no. of molecules of oxygen
    • (d) x = physical state of KClO₃ and KCl; y = reaction condition; z = physical state of O₂
17. 11.
    A visually challenged student, has to perform a lab test to detect the presence of acid in a given solution. The acid-base indicator preferred by him will be:

    • (a) Blue litmus
    • (b) Clove oil
    • (c) Red cabbage extract
    • (d) Hibiscus extract
18. 12.
    On the basis of electronic configuration of ⁹₅X, the group number and period of the element 'X' is:

    • (a) Group 15 period 2
    • (b) Group 13 period 2
    • (c) Group 9 period 5
    • (d) Group 13 period 5
19. 13.
    For questions 13 and 14, two statements are given — one labelled Assertion (A) and the other labelled as Reason (R). Select the correct answer from the codes (a), (b), (c) and (d): (a) Both (A) and (R) are true and (R) is correct explanation of the assertion. (b) Both (A) and (R) are true but (R) is not the correct explanation of the assertion. (c) (A) is true but (R) is false. (d) (A) is false…
20. 14.
    Assertion (A): The metals and alloys are good conductors of electricity. Reason (R): Bronze is an alloy of copper and tin and it is not a good conductor of electricity.
21. 15.
    A compound 'A' is used in the manufacture of cement. When dissolved in water, it evolves a large amount of heat and forms compound 'B'.

    • (i) Identify A and B.
    • (ii) Write the chemical equation for the reaction of A with water.
    • (iii) List two types of reactions in which this reaction may be classified.
22. 16.
    Give reasons for the following:

    • (i) Only one half of a water molecule is shown in the formula of Plaster of Paris.
    • (ii) Sodium hydrogen carbonate is used as an antacid.
    • (iii) On strong heating, blue coloured copper sulphate crystals turn white.
23. 17.
    From the elements ³⁹₁₉A, ²⁸₁₄B, ¹⁶₈C and ⁴⁰₁₈D identify:

    • (a) the most electro positive element.
    • (b) a noble gas.
    • (c) a metalloid.
    • (d) an element which will gain 2 electrons to attain nearest noble gas configuration.
    • (e) formula of compound formed between A and C.
    • (f) elements belonging to same period.
24. 18.
    Construct a terrestrial food chain comprising four trophic levels. (b) What will happen if we kill all the organisms in one trophic level? (c) Calculate the amount of energy available to the organisms at the fourth trophic level if the energy available to the organisms at the second trophic level is 2000 J.
25. 19.
    Complete the following flow chart as per the given instructions: Gastric Glands Present in the wall of Stomach → Secretions → (a), (b), (c) Each secretion has a Function: (d), (e), (f) respectively. Identify the three secretions (a, b, c) and their functions (d, e, f).
26. 20.
    Explain giving an example how the following provide evidences in favour of evolution in organisms.

    • (i) Homologous organs
    • (ii) Fossils
27. 21.
    What are chromosomes? Explain how in sexually reproducing organisms the number of chromosomes in the progeny is maintained.
28. 22.
    What happens after refraction, when:

    • (i) a ray of light parallel to the principal axis passes through a concave lens?
    • (ii) a ray of light falls on a convex lens while passing through its principal focus?
    • (iii) a ray of light passes through the optical centre of a convex lens?
29. 23.
    Two coils of insulated copper wire are wound over a non-conducting cylinder as shown. Coil 1 has comparative large number of turns. State your observations, when:

    • (i) Key K is closed.
    • (ii) Key K is opened. Give reason for each of your observations.
30. 24.
    List two causes of hypermetropia. (b) Draw ray diagrams showing (i) a hypermetropic eye and (ii) its correction using suitable optical device.
31. 25.
    What are conventional sources of energy? Name any two conventional sources of energy and state their one limitation each. (b) Burning of fossil fuels is a major cause of global warming. Give reason and suggest what steps you would take to reduce global warming. List any four steps. OR What is meant by 'bio-gas'? Name the main components of bio-gas. Explain the working of a bio-gas plant with the…
32. 26.
    What is a homologous series? Explain with an example. (b) Define the following terms giving one example of each. (i) Esterification (ii) Addition reaction
33. 27.
    Describe the structure and function of the basic filtering unit of kidney. (b) List two factors on which reabsorption of water from urine depends.
34. 28.
    List three different categories of contraception methods. (b) Why has Government of India prohibited prenatal sex determination by law? State its benefits in the long run. (c) Unsafe sexual act can lead to various infections. Name two bacterial and two viral infections caused due to unsafe sex.
35. 29.
    Find the ratio of resistances of two copper rods X and Y of lengths 30 cm and 10 cm respectively and having radii 2 cm and 1 cm respectively. (b) A current of 500 mA flows in a series circuit containing an electric lamp and a conductor of 10 Ω when connected to a 6 V battery. Find the resistance of the electric lamp.
36. 30.
    A concave mirror of focal length 10 cm can produce a magnified real as well as virtual image of an object placed in front of it. Draw ray diagrams to justify this statement. (b) An object is placed perpendicular to the principal axis of a convex mirror of focal length 10 cm. The distance of the object from the pole of the mirror is 10 cm. Find the position of the image formed.

Class 10 Science exam pattern (80 marks)

The theory paper carries 80 marks over 3 hours (39 questions, with internal choice in some). Section-wise structure:

Structure per the CBSE 2023-24 sample-paper design; question wording varies by set.

Prepare with

How to use these papers

1. 1Start chapter-wise early in the year — solve only the Science questions from a chapter you have just finished.
2. 2Switch to full timed papers 2–3 months before the exam: one complete set in the real time limit, no notes.
3. 3Self-mark against the marking scheme, then fix every mistake with our free NCERT solutions.
4. 4Re-attempt your weakest chapters until the recurring question types feel routine.

CBSE Class 10 Science 2020 paper — FAQ