CBSE Class 10 Science · Exam Practice

Science Practice Paper — Set 1

Science Practice Paper — Set 1. CBSE Class 10 Science, covering chemical reactions, acids, bases and salts, metals, carbon compounds, life processes, heredity, light, electricity and the environment, with a full answer key and worked solutions.

🎯 Full Marks: 50⏱️ Time: 1½ Hours📝 Questions: 30
SectionType of questionsQsMarks
AMultiple Choice Questions1010
BFill in the Blanks & True / False88
CShort Answer Questions816
DProblem Solving416
Total3050
Before you start
  • This paper samples across the CBSE Class 10 Science chapters on MuskMeadow: chemical reactions, acids, bases and salts, metals, carbon compounds, life processes, heredity, light, electricity and the environment.
  • Attempt the paper first, without looking at the answer key at the bottom of the page.
  • Show your working for Sections C and D — method marks are given even if the final answer is wrong.
  • This is a MuskMeadow practice paper. It is not an official CBSE paper and its mark scheme does not copy the board's exact pattern.
10 MARKS

Section A — Multiple Choice Questions

Choose the correct option. (1 mark each)

1. Fe + CuSO₄ → FeSO₄ + Cu is an example of a

A. combination reactionB. decomposition reactionC. displacement reactionD. double displacement reaction

2. The pH of a neutral solution at 25 °C is

A. 0B. 7C. 10D. 14

3. The chemical formula of baking soda is

A. Na₂CO₃B. NaHCO₃C. CaCO₃D. NaOH

4. Which of these metals is the most reactive?

A. CopperB. ZincC. SodiumD. Iron

5. The general formula of the alkane series is

A. CₙH₂ₙB. CₙH₂ₙ₊₂C. CₙH₂ₙ₋₂D. CₙHₙ

6. Loss of water vapour from the aerial parts of a plant through stomata is called

A. transpirationB. translocationC. respirationD. excretion

7. A concave mirror has a radius of curvature of 30 cm. Its focal length is

A. 60 cmB. 30 cmC. 15 cmD. 7.5 cm

8. The power of a lens of focal length 25 cm is

A. +4 DB. +0.04 DC. −4 DD. +25 D

9. A potential difference of 6 V is applied across a 3 Ω resistor. The current is

A. 18 AB. 0.5 AC. 2 AD. 9 A

10. In Mendel’s monohybrid cross, the phenotypic ratio in the F₂ generation is

A. 1 : 1B. 3 : 1C. 9 : 3 : 3 : 1D. 1 : 2 : 1
8 MARKS

Section B — Fill in the Blanks & True / False

Fill in each blank, or write True / False. (1 mark each)

11. The hormone that lowers blood sugar level is ______.

12. The structural and functional unit of the kidney is the ______.

13. Rusting of iron is a chemical change. (   )

14. The SI unit of electrical resistance is the ______.

15. Aluminium oxide is an amphoteric oxide. (   )

16. An electric ______ converts mechanical energy into electrical energy.

17. The ozone layer protects living things from harmful ultraviolet radiation. (   )

18. The sex of a human child is decided by the chromosome inherited from the ______ (father/mother).

16 MARKS

Section C — Short Answer Questions

Show your working. (2 marks each)

19. Balance the equation: Fe + H₂O → Fe₃O₄ + H₂.

20. Why is sodium stored under kerosene?

21. Find the power of a concave lens of focal length 50 cm.

22. An electric bulb draws 0.5 A from a 220 V supply. Find its power.

23. State Fleming’s left-hand rule.

24. Name the plant hormone responsible for the bending of a shoot towards light.

25. Write the molecular formula and name of the first member of the alkene series.

26. In a food chain, producers hold 10,000 J of energy. Using the 10% law, how much energy reaches the secondary consumer (third trophic level)?

16 MARKS

Section D — Problem Solving

Show all steps. (4 marks each)

27. An object is placed 30 cm in front of a convex lens of focal length 10 cm. Find (a) the image distance, (b) the magnification and (c) the nature of the image.

28. Resistors of 4 Ω and 6 Ω are connected in parallel across a 12 V battery. Find (a) the equivalent resistance, (b) the current in each resistor and (c) the total current drawn.

29. (a) Write the balanced equation for the neutralisation of hydrochloric acid with sodium hydroxide. (b) Calculate the pH of a solution of HCl in which [H⁺] = 10⁻³ mol/L. (c) Will the pH rise or fall if sodium hydroxide is added gradually? Why?

30. A pure tall pea plant (TT) is crossed with a dwarf plant (tt). (a) State the genotype and phenotype of the F₁. (b) Show the F₂ genotypic and phenotypic ratios. (c) If 400 plants are raised in F₂, how many are expected to be tall?

CBSE Class 10 Science · Science Practice Paper — Set 1 · Answer Key

Answers & Worked Solutions

Check your paper, then read the solutions for the questions you missed.

Section A — Multiple Choice Questions (10 marks)
Q1. C. displacement reaction

More reactive iron displaces copper from its salt solution.

Q2. B. 7

Pure water and neutral solutions have pH 7.

Q3. B. NaHCO₃

Baking soda is sodium hydrogencarbonate, NaHCO₃.

Q4. C. Sodium

Sodium is highest in the reactivity series among these.

Q5. B. CₙH₂ₙ₊₂

Alkanes are saturated hydrocarbons with formula CₙH₂ₙ₊₂.

Q6. A. transpiration

This is transpiration; it also helps pull water up the plant.

Q7. C. 15 cm

f = R/2 = 30/2 = 15 cm.

Q8. A. +4 D

P = 1/f (in metres) = 1/0.25 = +4 D (convex lens).

Q9. C. 2 A

I = V/R = 6/3 = 2 A.

Q10. B. 3 : 1

Three tall plants to one dwarf plant (3 : 1); the genotypic ratio is 1 : 2 : 1.

Section B — Fill in the Blanks & True / False (8 marks)
Q11. insulin

Insulin from the pancreas helps cells take up glucose.

Q12. nephron

Each kidney has about a million nephrons that filter blood.

Q13. True

A new substance, hydrated iron(III) oxide, forms.

Q14. ohm

1 Ω = 1 V/A.

Q15. True

It reacts with both acids and bases to form salt and water.

Q16. generator

It works on electromagnetic induction.

Q17. True

Ozone in the stratosphere absorbs UV rays from the Sun.

Q18. father

The mother always gives X; the father gives X (girl) or Y (boy).

Section C — Short Answer Questions (16 marks)
Q19. 3Fe + 4H₂O → Fe₃O₄ + 4H₂
  1. Balance O first: 4 H₂O gives 4 O atoms for Fe₃O₄.
  2. Then 3 Fe on the left and 4 H₂ on the right: 3Fe + 4H₂O → Fe₃O₄ + 4H₂ (H: 8 = 8, O: 4 = 4).
Q20. It reacts vigorously with air and water
  1. Sodium is highly reactive and reacts violently with oxygen and moisture in air.
  2. Kerosene keeps it out of contact with air and water, preventing fire.
Q21. −2 D
  1. f = −0.5 m for a concave lens.
  2. P = 1/f = 1/(−0.5) = −2 D.
Q22. 110 W
  1. P = V × I.
  2. P = 220 × 0.5 = 110 W.
Q23. Thumb = force, forefinger = field, middle finger = current
  1. Stretch the thumb, forefinger and middle finger of the left hand mutually perpendicular.
  2. If the forefinger shows the field and the middle finger the current, the thumb shows the direction of force on the conductor.
Q24. Auxin
  1. Auxin collects on the shaded side of the shoot.
  2. It makes cells on that side grow longer, so the shoot bends towards the light.
Q25. C₂H₄, ethene
  1. Alkenes have the general formula CₙH₂ₙ and contain a double bond, so n starts at 2.
  2. The first member is ethene, C₂H₄.
Q26. 100 J
  1. Producers → primary consumers: 10% of 10,000 = 1000 J.
  2. Primary → secondary consumers: 10% of 1000 = 100 J.
Section D — Problem Solving (16 marks)
Q27. (a) 15 cm (b) −0.5 (c) real, inverted, diminished
  1. Sign convention: u = −30 cm, f = +10 cm.
  2. (a) 1/v = 1/f + 1/u = 1/10 − 1/30 = 2/30, so v = +15 cm (on the other side of the lens).
  3. (b) m = v/u = 15/(−30) = −0.5.
  4. (c) v is positive, so the image is real; m is negative and |m| < 1, so it is inverted and diminished.
Q28. (a) 2.4 Ω (b) 3 A and 2 A (c) 5 A
  1. (a) 1/R = 1/4 + 1/6 = 5/12, so R = 2.4 Ω.
  2. (b) Each resistor has 12 V across it: I₁ = 12/4 = 3 A, I₂ = 12/6 = 2 A.
  3. (c) Total current I = 3 + 2 = 5 A; check: 12/2.4 = 5 A ✓.
Q29. (a) HCl + NaOH → NaCl + H₂O (b) 3 (c) rises
  1. (a) HCl + NaOH → NaCl + H₂O (salt and water).
  2. (b) pH = −log₁₀[H⁺] = −log₁₀(10⁻³) = 3.
  3. (c) The pH rises: NaOH neutralises the H⁺ ions, so [H⁺] falls and the solution moves towards pH 7 and then into the basic range.
Q30. (a) Tt, all tall (b) 1:2:1 and 3:1 (c) 300
  1. (a) Gametes T and t combine to give all Tt; T is dominant, so all F₁ plants are tall.
  2. (b) Selfing Tt × Tt gives TT : Tt : tt = 1 : 2 : 1 (genotypes), i.e. 3 tall : 1 dwarf (phenotypes).
  3. (c) Tall = 3/4 of 400 = 300 plants.
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