CBSE Class 10 Science 2020 — Set 5

Questions in this 2020 Science paper (Set 5)

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 are generally poor conductors of electricity. Why?

   • (a) They have strong intermolecular forces
   • (b) They have high melting and boiling points
   • (c) They do not form ions in solution or in molten state
   • (d) They are made up of metals and non-metals
2. 2.
   State the common characteristic of the following elements: Boron, Silicon, Germanium and Arsenic
3. 3 (a).
   Read the following passage and answer questions 3(a) to 3(d): Solar power in India is a fast developing industry. The country … (a) What are solar cells?
4. 3 (b).
   (Based on Solar Energy passage) 3(b) How much voltage can be developed and how much electricity can be produced by one typical solar cell when exposed to the Sun?
5. 3 (c).
   (Based on Solar Energy passage) 3(c) The future of power generation by solar energy is bright in India. Give reason.
6. 3 (d).
   (Based on Solar Energy passage) 3(d) List two advantages of solar cells.
7. 4 (a).
   Read the following passage and answer questions 4(a) to 4(d): Thyroid Stimulating Hormone (TSH) stimulates thyroid gland to produce thyroxine. Study the table given below: Table: TSH levels during pregnancy Stage of pregnancy | Normal (mIU/L) | Low (mIU/L) | High (mIU/L) First trimester | 0.2–2.5 | <0.2 | 2.5–10 Second trimester | 0.3–3.0 | <0.3 | 3.01–4.5 Third trimester | 0.8–5.2 | <0.8 | >5.3…
8. 4 (b).
   (Based on TSH passage) 4(b) State the main function of TSH.
9. 4 (c).
   (Based on TSH passage) 4(c) Why do TSH levels in pregnant women need to be monitored?
10. 4 (d).
    (Based on TSH passage) 4(d) A pregnant woman has TSH level of 8.95 mIU/L. What care is needed for her?
11. 5.
    The image distance from the eye lens in the normal eye when we increase the distance of an object from the eye:

    • (a) increases
    • (b) decreases
    • (c) remains unchanged
    • (d) depends on the size of the eyeball
12. 6.
    The values of mA and μA are:

    • (a) 10⁻⁶ A and 10⁻⁹ A respectively
    • (b) 10⁻³ A and 10⁻⁶ A respectively
    • (c) 10⁻³ A and 10⁻⁹ A respectively
    • (d) 10⁻⁶ A and 10⁻³ A respectively
13. 7.
    A cylindrical conductor of length 'l' and uniform area of cross-section 'A' has resistance 'R'. Another conductor of length 2.5l and resistance 0.5R of the same material has area of cross-section:

    • (a) 5A
    • (b) 2.5A
    • (c) 0.5A
    • (d) (1/5)A
14. 8.
    Consider the following criticisms that are generally addressed when a new project is launched: I. Displacement of peasants and local tribals without compensation. II. Swallowing up large amount of public money without any benefits. III. Deforestation and loss of biodiversity. The criticisms about large dams in particular are:

    • (a) I and II
    • (b) II and III
    • (c) I and III
    • (d) I, II and III
15. 9.
    The Reni village of Garhwal is famous for:

    • (a) Monocultures of pine, teak and eucalyptus
    • (b) Chipko Movement
    • (c) Extensive biodiversity
    • (d) Participation of local people in efficient management of forests
16. 10.
    Strong heating of ferrous sulphate leads to the formation of a brown solid and two gases. This reaction can be categorised as:

    • (a) displacement and redox
    • (b) decomposition and redox
    • (c) displacement and endothermic
    • (d) decomposition and exothermic
17. 11.
    If 10 mL of H₂SO₄ is mixed with 10 mL of Mg(OH)₂ of the same concentration, the resultant solution will give the following colour with universal indicator:

    • (a) Red
    • (b) Yellow
    • (c) Green
    • (d) Blue
18. 12.
    An element X with atomic number 12 forms a compound with element Y with atomic number 17. The formula of the compound formed is:

    • (a) XY
    • (b) XY₂
    • (c) X₂Y
    • (d) X₂Y₃
19. 13.
    For question numbers 13 and 14, two statements are given — one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the codes (i), (ii), (iii) and (iv) as given below: Assertion (A): Carbon has a strong tendency to either lose or gain electrons to attain noble gas configuration. Reason (R): Carbon has four electrons in its outermost shell and has the tendency…
20. 14.
    Assertion (A): At high temperatures, metal wires have a greater chance of short circuiting. Reason (R): Both resistivity and resistance of a material vary with temperature.

    • (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, but (R)…
21. 15.
    A shining metal 'M', on burning gives a dazzling white flame and changes to a white powder 'N'.

    • (a) Identify 'M' and 'N'.
    • (b) Represent the above reaction in the form of a balanced chemical equation.
    • (c) Does 'M' undergo oxidation or reduction in this reaction? Justify.
22. 16.
    In the electrolysis of water:

    • (a) Name the gases liberated at anode and cathode.
    • (b) Why is it that the volume of gas collected on one electrode is two times that on the other electrode?
    • (c) What would happen if dil. H₂SO₄ is not added to water?
23. 17.
    From the elements Li, K, Mg, C, Al, S identify the:

    • (a) elements belonging to the same group
    • (b) element which has the tendency to lose two electrons
    • (c) element which prefers sharing of electrons to complete its octet (gives priority to sharing electrons)
    • (d) most metallic element
    • (e) element that forms acidic oxide
    • (f) element that belongs to group 13
24. 18.
    What is meant by trophic level in a food chain? Construct a terrestrial food chain with four trophic levels. The energy flow in a food chain is always unidirectional. Why?
25. 19 (a).
    19(a) In the process of respiration, state the function of alveoli.
26. 19 (b).
    19(b) Rate of breathing in aquatic organisms is much faster than that in terrestrial organisms. Give reasons.
27. 19 (c).
    19(c) Complete the following pathway showing the breakdown of glucose: Glucose (6-carbon molecule) → cytoplasm →

    • (i) ? (3-carbon molecule) + energy Then in the presence of O₂:
    • (i) ? → in mitochondria →
    • (ii) ? + H₂O + energy In absence of O₂:
    • (i) ? →
    • (iii) ? + energy
28. 20 (a).
    20(a) Why is the F1 progeny always of tall plants when a tall pea plant is crossed with a short pea plant?
29. 20 (b).
    20(b) How is F2 progeny obtained by self-pollination of F1 progeny different from F1 progeny? Give reason for this observation.
30. 20 (c).
    20(c) State a conclusion that can be drawn on the basis of this observation.
31. 21 (a).
    21(a) What provides nutrition to human sperms? State the genetic constitution of a sperm.
32. 21 (b).
    21(b) Mention the chromosome pair present in a zygote which determines the sex of

    • (i) a female child, and
    • (ii) a male child.
33. 22.
    Draw ray diagram in each of the following cases to show what happens after reflection to the incident ray when:

    • (a) it is parallel to the principal axis and falling on a convex mirror.
    • (b) it is falling on a concave mirror while passing through its principal focus.
    • (c) it is coming oblique to the principal axis and falling on the pole of a convex mirror.
34. 23.
    A coil of insulated wire is connected to a galvanometer. What would be observed if a strong bar magnet with its south pole towards one face of the coil is:

    • (i) moved quickly towards it?
    • (ii) moved quickly away from it?
    • (iii) held stationary near it? Name the phenomenon involved. State the conclusion based on the observations in (i),
    • (ii) and (iii).
35. 24 (a).
    A short uses spectacles of focal length – 2.5 m. (a) Name the defect of vision he is suffering from.
36. 24 (b).
    24(b) Which lens is used for the correction of this defect?
37. 24 (c).
    24(c) List two main causes of developing this defect.
38. 24 (d).
    24(d) Compute the power of this lens.
39. 25.
    Two ores X and Y were taken. On heating these ores it was observed that:

    • (a) ore X gives CO₂ gas, and
    • (b) ore Y gives SO₂ gas. Write steps to convert these ores into metals, giving chemical equations of the reactions that take place.
40. 26 (a).
    26(a) Define isomerism. Draw all possible isomers of butane.
41. 26 (b).
    26(b) 'A compound X on combustion gives a yellow flame with lots of smoke.' What inference would you draw from this statement?
42. 26 (c).
    26(c) State the role of alkaline KMnO₄ in the reaction involving conversion of an alcohol to corresponding carboxylic acid.
43. 27 (a).
    Give reasons: (a) Ventricles have thicker muscular walls than atria.
44. 27 (b).
    Give reasons: (b) Transport system in plants is slow.
45. 27 (c).
    Give reasons: (c) Circulation of blood in aquatic vertebrates differs from that in terrestrial vertebrates.
46. 27 (d).
    Give reasons: (d) During the daytime, water and minerals travel faster through xylem as compared to the night.
47. 27 (e).
    Give reasons: (e) Veins have valves whereas arteries do not.
48. 28.
    Based on the given diagram of the male reproductive system, answer the questions given below:

    • (a) Label the parts A, B, C and D.
    • (b) Name the hormone secreted by testis and mention its role.
    • (c) State the functions of B and C in the process of reproduction.
49. 29 (a).
    Two lamps rated 100 W, 220 V and 10 W, 220 V are connected in parallel to a 220 V supply. Calculate the total current through the circuit.
50. 29 (b).
    Two resistors X and Y of resistances 2 Ω and 3 Ω respectively are first joined in parallel and then in series. In each case the voltage supplied is 5 V.

    • (i) Draw circuit diagrams to show the combination of resistors in each case.
    • (ii) Calculate the voltage across the 3 Ω resistor in the series combination of resistors.
51. 30 (a).
    30(a) Draw a labelled ray diagram to show the path of a ray of light incident obliquely on one face of a glass slab.
52. 30 (b).
    30(b) Calculate the refractive index of the material of a glass slab. Given that the speed of light through the glass slab is 2 × 10⁸ m/s and in air is 3 × 10⁸ m/s.
53. 30 (c).
    30(c) Calculate the focal length of a lens, if its power is – 2.5 D.

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