Science · Sample Paper 1

General instructions

Section A · Objective

1. Question 11 mark

   In which state of matter is the rate of diffusion the highest?

   1. A.Solid
   2. B.Liquid
   3. C.Gas
   4. D.It is the same in all three
2. Question 21 mark

   The boiling point of water at normal atmospheric pressure, on the Kelvin scale, is about

   1. A.273 K
   2. B.373 K
   3. C.100 K
   4. D.0 K
3. Question 31 mark

   Which of the following is a homogeneous mixture?

   1. A.Sand and water
   2. B.Muddy water
   3. C.Sugar dissolved in water
   4. D.Oil and water
4. Question 41 mark

   Which of the following shows the Tyndall effect?

   1. A.Salt solution
   2. B.Sugar solution
   3. C.Milk
   4. D.Copper sulphate solution
5. Question 51 mark

   The chemical formula of aluminium sulphate is

   1. A.AlSO₄
   2. B.Al₂SO₄
   3. C.Al₂(SO₄)₃
   4. D.Al₃(SO₄)₂
6. Question 61 mark

   The number of particles in one mole of a substance is

   1. A.6.022 × 10²³
   2. B.6.022 × 10²²
   3. C.1.66 × 10⁻²⁴
   4. D.3.011 × 10²³
7. Question 71 mark

   An element has the electronic configuration 2, 8, 3. Its atomic number is

   1. A.11
   2. B.12
   3. C.13
   4. D.3
8. Question 81 mark

   Isotopes of an element have

   1. A.the same mass number but different atomic numbers
   2. B.the same atomic number but different mass numbers
   3. C.the same number of neutrons
   4. D.different numbers of protons
9. Question 91 mark

   Which cell organelle is known as the powerhouse of the cell?

   1. A.Ribosome
   2. B.Mitochondrion
   3. C.Golgi apparatus
   4. D.Lysosome
10. Question 101 mark

    Which of the following is absent in an animal cell?

    1. A.Cell membrane
    2. B.Nucleus
    3. C.Cell wall
    4. D.Mitochondria
11. Question 111 mark

    Which tissue connects a muscle to a bone?

    1. A.Ligament
    2. B.Tendon
    3. C.Cartilage
    4. D.Areolar tissue
12. Question 121 mark

    A car moves with a uniform velocity. Its acceleration is

    1. A.zero
    2. B.constant but not zero
    3. C.increasing
    4. D.decreasing
13. Question 131 mark

    The SI unit of momentum is

    1. A.kg m/s²
    2. B.kg m/s
    3. C.N/s
    4. D.J s
14. Question 141 mark

    The acceleration due to gravity on the surface of the Moon is about

    1. A.half of that on the Earth
    2. B.one-sixth of that on the Earth
    3. C.six times that on the Earth
    4. D.the same as on the Earth
15. Question 151 mark

    A body of mass 2 kg moves with a speed of 3 m/s. Its kinetic energy is

    1. A.6 J
    2. B.9 J
    3. C.18 J
    4. D.3 J
16. Question 161 mark

    Sound cannot travel through

    1. A.water
    2. B.steel
    3. C.air
    4. D.vacuum
17. Question 171 mark

    Assertion (A): Evaporation causes cooling.

    Reason (R): During evaporation, the particles of the liquid absorb energy from the surroundings to regain the energy they lose, so the surroundings become cool.

    1. A.Both Assertion (A) and Reason (R) are true, and R is the correct explanation of A.
    2. B.Both Assertion (A) and Reason (R) are true, but R is not the correct explanation of A.
    3. C.Assertion (A) is true, but Reason (R) is false.
    4. D.Assertion (A) is false, but Reason (R) is true.
18. Question 181 mark

    Assertion (A): An atom is electrically neutral.

    Reason (R): An atom has equal numbers of protons and neutrons.

    1. A.Both Assertion (A) and Reason (R) are true, and R is the correct explanation of A.
    2. B.Both Assertion (A) and Reason (R) are true, but R is not the correct explanation of A.
    3. C.Assertion (A) is true, but Reason (R) is false.
    4. D.Assertion (A) is false, but Reason (R) is true.
19. Question 191 mark

    Assertion (A): An object weighs less on the Moon than on the Earth.

    Reason (R): The mass of an object changes from place to place.

    1. A.Both Assertion (A) and Reason (R) are true, and R is the correct explanation of A.
    2. B.Both Assertion (A) and Reason (R) are true, but R is not the correct explanation of A.
    3. C.Assertion (A) is true, but Reason (R) is false.
    4. D.Assertion (A) is false, but Reason (R) is true.
20. Question 201 mark

    Assertion (A): Adding manure improves the texture of the soil.

    Reason (R): Manure adds organic matter (humus) to the soil.

    1. A.Both Assertion (A) and Reason (R) are true, and R is the correct explanation of A.
    2. B.Both Assertion (A) and Reason (R) are true, but R is not the correct explanation of A.
    3. C.Assertion (A) is true, but Reason (R) is false.
    4. D.Assertion (A) is false, but Reason (R) is true.

Section B · Very short answer

1. Question 212 marks

   Convert the following temperatures to the Celsius scale: (a) 300 K (b) 573 K

2. OR

   Question 212 marks

   Why do we see water droplets collected on the outer surface of a glass containing ice-cold water?

3. Question 222 marks

   Differentiate between a compound and a mixture. Give any two points.

4. Question 232 marks

   Calculate the molecular mass of H₂SO₄. (Atomic masses: H = 1 u, S = 32 u, O = 16 u)

5. OR

   Question 232 marks

   How many moles are present in 52 g of helium? (Atomic mass of He = 4 u)

6. Question 242 marks

   Why is the plasma membrane called a selectively permeable membrane? Name one process by which substances move across it.

7. Question 252 marks

   A train starting from rest attains a speed of 72 km/h in 5 minutes. Find its acceleration, assuming it is uniform.

8. Question 262 marks

   A sound wave has a frequency of 220 Hz and travels at 440 m/s in a medium. Find (a) its wavelength (b) its time period.

Section C · Short answer

1. Question 273 marks

   Write the electronic configuration and the valency of: (a) sodium (atomic number 11) (b) chlorine (atomic number 17) (c) magnesium (atomic number 12)

2. Question 283 marks

   Give one location in the body and one feature of each of these muscle tissues: (a) striated muscle (b) smooth muscle (c) cardiac muscle

3. OR

   Question 283 marks

   Name the tissue that: (a) transports water and minerals in plants (b) stores fat in our body (c) connects two bones

4. Question 293 marks

   A bullet of mass 10 g, travelling horizontally at 150 m/s, strikes a stationary wooden block and comes to rest in 0.03 s. Calculate (a) the distance it penetrates into the block (b) the magnitude of the force exerted by the block on the bullet.

5. Question 303 marks

   State the universal law of gravitation. What happens to the force between two objects if the distance between them is halved?

6. OR

   Question 303 marks

   An object has a mass of 10 kg. Find (a) its weight on the Earth (b) its weight on the Moon (c) its mass on the Moon. (Take g = 9.8 m/s² on Earth; g on the Moon is one-sixth of that on Earth.)

7. Question 313 marks

   A boy of mass 40 kg runs up a staircase of 8 m vertical height in 10 s. Calculate (a) the work done by him against gravity (b) his power. (Take g = 10 m/s²)

8. Question 323 marks

   How would you separate a mixture of common salt, sand and iron filings? Write the steps in order.

9. Question 333 marks

   Distinguish between manure and fertilisers. Give three points.

Section D · Long answer

1. Question 345 marks

   (a) A car accelerates uniformly from 18 km/h to 36 km/h in 5 s. Calculate (i) its acceleration (ii) the distance it covers in that time.

   (b) Another car moving at 20 m/s is brought to rest by applying brakes that produce a uniform retardation of 4 m/s². How long does it take to stop, and how far does it travel before stopping?

2. OR

   Question 345 marks

   (a) Distinguish between distance and displacement, with an example.

   (b) An athlete completes one round of a circular track of radius 7 m in 20 s. Find the distance covered, the displacement at the end of 20 s, and the average speed. (Use π = 22/7)

3. Question 355 marks

   (a) Write three differences between a plant cell and an animal cell.

   (b) What would happen if the plasma membrane of a cell ruptures or breaks down?

4. OR

   Question 355 marks

   (a) What is osmosis?

   (b) What happens when (i) a plant cell is placed in a hypertonic solution (ii) an animal cell is placed in a hypotonic solution?

   (c) Why are lysosomes called 'suicide bags' of the cell?

5. Question 365 marks

   (a) State the law of conservation of mass and the law of constant proportions.

   (b) In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g of water and 8.2 g of sodium ethanoate. Show that these observations agree with the law of conservation of mass.

Section E · Case study

1. Question 374 marks

   Case study — SONAR. Ships use SONAR to measure the depth of the sea and to locate underwater objects. A transmitter sends out pulses of ultrasound, and a detector records the echo that returns after being reflected from the sea bed. Bats use a similar idea, called echolocation, to fly in the dark.

   (i) What is ultrasound? (1 mark)

   (ii) Give one use of ultrasound in medicine. (1 mark)

   (iii) A ship sends an ultrasonic pulse and receives the echo from the sea bed after 4 s. If sound travels at 1500 m/s in sea water, find the depth of the sea. (2 marks)

   OR

   (iii) For a distinct echo, the reflected sound must reach us at least 0.1 s after the original sound. If the speed of sound in air is 344 m/s, find the minimum distance of the reflecting surface. (2 marks)

2. Question 384 marks

   Case study — A falling ball. During a physics activity, students drop a ball of mass 2 kg from the top of a building 20 m high and discuss how its energy changes as it falls. Ignore air resistance and take g = 10 m/s².

   (i) What is the potential energy of the ball at the top? (1 mark)

   (ii) What is its kinetic energy just before it hits the ground? (1 mark)

   (iii) Find the speed of the ball when it is halfway down. (2 marks)

   OR

   (iii) State the law of conservation of energy and show that the total mechanical energy of the ball halfway down is the same as at the top. (2 marks)

3. Question 394 marks

   Case study — Composite fish culture. A farmer in West Bengal rears five or six species of fish together in one pond: catla, rohu, mrigal, common carp, grass carp and silver carp. Each species feeds in a different zone of the pond or on different food. His fish yield has increased considerably.

   (i) What is composite fish culture? (1 mark)

   (ii) Name one surface feeder among these fish. (1 mark)

   (iii) Why does composite fish culture give a higher yield? (2 marks)

   OR

   (iii) State one problem of composite fish culture and how it is overcome. (2 marks)