Quest4Learn
Sign in Start free

CBSE Class 10 Science 2024 — Paper 31(B)/S

80 marks · 3 hours · 39 questions (47 with the OR choices)

Take this paper as a timed mock

Free with an account: the board's time limit, marking at the end, and the answer to every question.

Sign up free Log in

Questions 1–20 · 1 mark each

  1. Q1 1 mark

    This question is in the full bank. Sign up free to see it.

  2. Q2 1 mark

    This question is in the full bank. Sign up free to see it.

  3. Q3 1 mark

    This question is in the full bank. Sign up free to see it.

  4. Q4 1 mark

    This question is in the full bank. Sign up free to see it.

  5. Q5 1 mark

    This question is in the full bank. Sign up free to see it.

  6. Q6 1 mark

    This question is in the full bank. Sign up free to see it.

  7. Q7 1 mark

    This question is in the full bank. Sign up free to see it.

  8. Q8 1 mark

    This question is in the full bank. Sign up free to see it.

  9. Q9 1 mark

    This question is in the full bank. Sign up free to see it.

  10. Q10 1 mark

    This question is in the full bank. Sign up free to see it.

  11. Q11 1 mark
    The direction of magnetic field produced around a current carrying straight conductor is determined by using :
    1. (a)Fleming’s left hand rule
    2. (b)Left hand thumb rule
    3. (c)Right hand thumb rule
    4. (d)Fleming’s right hand rule
    Show answer
    (c) Right hand thumb rule
    Step-by-step solution →
  12. Q12 1 mark

    This question is in the full bank. Sign up free to see it.

  13. Q13 1 mark
    When a steady current flows through a long straight solenoid it behaves as a bar magnet having a north and a south pole. The strength of the magnetic field inside the solenoid is :
    1. (a)zero everywhere.
    2. (b)uniform everywhere.
    3. (c)maximum at the ends and minimum at the centre.
    4. (d)minimum at the ends and maximum at the centre.
    Show answer
    (b) uniform everywhere.
    Step-by-step solution →
  14. Q14 1 mark
    You have four resistance wires of same material. Select the wire which will offer the least resistance to the flow of current in an electric circuit :
    1. (a)Length and diameter
    2. (b)Length and diameter
    3. (c)Length and diameter
    4. (d)Length and diameter
    Show answer
    (a) Length and diameter
    Step-by-step solution →
  15. Q15 1 mark

    This question is in the full bank. Sign up free to see it.

  16. Q16 1 mark
    The resistance of a resistor is increased four times its initial value. If other parameters (current and time) remain unchanged, the percentage change in the amount of heat produced in the resistor would be :
    1. (a)100%
    2. (b)200%
    3. (c)300%
    4. (d)400%
    Show answer
    (c) 300%
    Step-by-step solution →
  17. Q17 1 mark
    Two statements are given — one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the codes (a), (b), (c) and (d) as given below.

    Assertion (A): Magnetic field lines never intersect each other.

    Reason (R): If two field lines intersect each other at a point then it would mean that at the point of intersection the resultant field has two directions, which is not possible.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer
    (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    Step-by-step solution →
  18. Q18 1 mark

    This question is in the full bank. Sign up free to see it.

  19. Q19 1 mark

    This question is in the full bank. Sign up free to see it.

  20. Q20 1 mark

    This question is in the full bank. Sign up free to see it.

Questions 21–26 · 2 marks each

  1. Q21 2 marks

    This question is in the full bank. Sign up free to see it.

  2. Q22(a) 2 marks

    This question is in the full bank. Sign up free to see it.

    OR
    Q22(b) 2 marks

    This question is in the full bank. Sign up free to see it.

  3. Q23 2 marks

    This question is in the full bank. Sign up free to see it.

  4. Q24 2 marks

    This question is in the full bank. Sign up free to see it.

  5. Q25(a) 2 marks
    The far point of a defective eye is nearer than infinity.
    1. (i)Identify the defect of vision.
    2. (ii)List two possible causes responsible for this defect.
    3. (iii)Name the type of lens (converging/diverging) used for the correction of this defect.
    Show answer

    Myopia; caused by excessive lens curvature or an elongated eyeball; corrected by a diverging (concave) lens.

    (i) The defect is myopia (near-sightedness). (ii) Causes: excessive curvature of the eye lens; elongation of the eyeball. (iii) A diverging lens, that is, a concave lens of suitable power.
    Step-by-step solution →
    OR
    Q25(b) 2 marks
    “The colour of the clear sky from the earth appears blue but the sky appears dark to the passengers flying at very high altitudes.” Explain.
    Show answer

    Scattered blue light makes the sky blue; at high altitude there is too little air to scatter light, so the sky looks dark.

    From the earth, the clear sky looks blue because the molecules of air and other fine particles in the atmosphere, being smaller than the wavelength of visible light, scatter blue light (shorter wavelength) much more strongly than red light; this scattered blue light enters our eyes. At very high altitudes there is hardly any air to scatter sunlight, so scattering is not prominent and very little scattered light reaches the passengers' eyes: the sky appears dark.
    Step-by-step solution →
  6. Q26(a) 2 marks

    This question is in the full bank. Sign up free to see it.

    OR
    Q26(b) 2 marks

    This question is in the full bank. Sign up free to see it.

Questions 27–33 · 3 marks each

  1. Q27 3 marks

    This question is in the full bank. Sign up free to see it.

  2. Q28 3 marks

    This question is in the full bank. Sign up free to see it.

  3. Q29(a) 3 marks

    This question is in the full bank. Sign up free to see it.

    OR
    Q29(b) 3 marks

    This question is in the full bank. Sign up free to see it.

  4. Q30 3 marks

    This question is in the full bank. Sign up free to see it.

  5. Q31(a) 3 marks
    A student has focussed the image of an object of height 5 cm on a screen using a convex lens of focal length 20 cm. If the object distance is 30 cm find, using lens formula, the
    1. (i)image distance and
    2. (ii)height of the image produced.
    Show answer

    cm and cm: the image is 10 cm tall and inverted, formed 60 cm from the lens.

    (i) Image distance cm: the image is formed cm from the lens, on the side opposite to the object, where the screen is. (ii) Height of the image cm: the image is cm tall and inverted (magnification ).
    Step-by-step solution →
    OR
    Q31(b) 3 marks
    Define power of a lens. The focal length of a lens is cm. Determine its nature (converging/diverging) and calculate its power. If an object is placed at a distance of 50 cm from the optical centre of this lens, list two properties of the image formed in this case.
    Show answer

    The lens is convex (converging) with power D; an object at 50 cm gives a real, inverted image of the same size.

    Power of a lens: the degree of convergence or divergence of light rays achieved by a lens. It is the reciprocal of its focal length in metres, , and its SI unit is the dioptre (D); D is the power of a lens of focal length m. Nature: the focal length is positive, so the lens is convex, that is converging. Power: D. Image of an object at cm, that is at : it is formed at , cm behind the lens ( cm, ). Two properties: (1) it is real and inverted; (2) it is of the same size as the object.
    Step-by-step solution →
  6. Q32(a) 3 marks
    Define the term dispersion of white light. State the colour of light which bends
    1. (i)the least,
    2. (ii)the most, while passing through a glass prism. Also, state the cause of dispersion of a narrow beam of white light when it passes through a prism.
    Show answer

    Dispersion is the splitting of white light into colours; red bends the least and violet the most.

    Dispersion: the splitting of white light into its component colours (violet, indigo, blue, green, yellow, orange and red) when it passes through a prism. (i) Red light bends the least. (ii) Violet light bends the most. Cause: light of different colours travels through glass with different speeds, so the refractive index of glass is different for each colour (smallest for red, largest for violet). The colours are therefore refracted through different angles with respect to the incident ray, emerge along different paths and become separated.
    Step-by-step solution →
    OR
    Q32(b) 3 marks
    When and where does a rainbow appear in the sky ? Write sequence-wise the phenomena of light responsible for the formation of a rainbow. List two essential conditions for observing a rainbow.
    Show answer

    A rainbow forms after rain, opposite the Sun, by refraction with dispersion, internal reflection and refraction again in water droplets.

    When and where: a rainbow appears in the sky after a rain shower, when the Sun is shining and tiny water droplets are still present in the atmosphere; it is always formed in the direction opposite to that of the Sun. Phenomena, in sequence: (1) refraction of sunlight as it enters a raindrop, which also disperses it into its colours; (2) internal reflection of the light at the back surface of the drop; (3) refraction of the light again as it comes out of the drop. Two essential conditions: (1) the Sun must be behind the observer; (2) there must be tiny water droplets in the air in front of the observer, as after rain or in the spray of a waterfall or a fountain.
    Step-by-step solution →
  7. Q33 3 marks
    1. (a)How is the type of current used in household supply different from the current given by a battery of dry cells ?
    2. (b)Which one of the two currents mentioned above in (a) is considered to be more advantageous for the long distance transmission of electric power and why ? (c) How does the electric fuse prevent the electric circuit and the appliances from a possible damage due to short circuiting ?
    Show answer

    Household supply is AC (direction reverses) and a battery gives DC; AC suits long-distance transmission; a fuse melts to break the circuit.

    (a) The household supply is alternating current (AC), which reverses its direction periodically; in India it changes direction every s (frequency Hz). A battery of dry cells gives direct current (DC), which flows in one direction only. (b) AC is more advantageous, because electric power can be transmitted over long distances as AC without much loss of energy: its voltage can easily be raised for transmission, so the current in the wires, and hence the heat wasted in them, is small, and it can be lowered again before use. (c) A fuse is a wire of low melting point connected in series in the live wire. In a short circuit the live and neutral wires touch, the resistance becomes very small and the current increases abruptly. This unduly high current heats the fuse wire (Joule heating) until it melts, which breaks the circuit and stops the current, so the circuit and the appliances are not damaged.
    Step-by-step solution →

Questions 34–36 · 5 marks each

  1. Q34(a) 5 marks

    This question is in the full bank. Sign up free to see it.

    OR
    Q34(b) 5 marks

    This question is in the full bank. Sign up free to see it.

  2. Q35(a) 5 marks

    This question is in the full bank. Sign up free to see it.

    OR
    Q35(b) 5 marks

    This question is in the full bank. Sign up free to see it.

  3. Q36 5 marks
    1. (a)List two factors on which the resistance of a conductor in the shape of a straight cylinder depends. Write the relation between resistance () and the resistivity () of the material of the conductor. Use this relation to obtain the SI unit of resistivity.
    2. (b)Resistance of a metal wire of length 1 m is . If the area of cross-section of the wire is , find the resistivity of the material of the wire.
    Show answer

    Resistance depends on length and area of cross-section; gives the unit ; .

    (a) The resistance of a cylindrical conductor depends on (1) its length , , and (2) its area of cross-section , (for a given material at a given temperature). Relation: , so , and the SI unit of resistivity is (ohm metre). (b) .
    Step-by-step solution →

Questions 37–39 · 4 marks each

  1. Q37 4 marks

    This question is in the full bank. Sign up free to see it.

  2. Q38 4 marks

    This question is in the full bank. Sign up free to see it.

  3. Q39 4 marks
    Under the guidance of his teacher on a sunny day, a student took a concave mirror of large aperture in his hand and directed its reflecting surface towards the sun. After that he directed the light reflected by the concave mirror on a thick sheet of white paper held close to the mirror. He observed a bright circular spot of light on the paper. Then he moved the mirror back and forth gradually until he got the brightest and smallest spot of light on the paper. The teacher said this sharp spot of light is, in fact, the real and inverted image of the sun and the distance between the mirror and this image is the focal length of this concave mirror.
    1. (a)Define the term principal focus of a concave mirror.[1]
    2. (b)If the distance between the pole and focus of a concave mirror is 12 cm, what is the radius of curvature of the mirror ?[1]
    3. (c)(i)List two properties of the image formed due to a concave mirror of focal length 15 cm in each of the following cases : (1) object distance 20 cm (2) object distance 10 cm[2]
    4. (c)(ii)OR : A 3 cm long candle flame is placed in front of a concave mirror. If the distance between the pole and the candle flame is 40 cm and the image is formed at the same place where the candle flame is located, find the (1) focal length of the mirror, and (2) magnification of the image formed with sign as per the New Cartesian Sign Convention.[2]
    Show answer

    Radius of curvature cm; image real and inverted at 20 cm, virtual and erect at 10 cm; or cm and .

    (a) The principal focus of a concave mirror is the point on its principal axis at which rays of light incident parallel to the principal axis meet after reflection from the mirror. (b) cm. (c)(i) (1) Object at cm (between and ): cm, ; the image is real and inverted (also enlarged, formed beyond ). (2) Object at cm (between and ): cm, ; the image is virtual and erect (also enlarged, formed behind the mirror). OR (c)(ii) (1) With cm, , so cm (focal length cm). (2) : the image is real, inverted and of the same size ( cm).
    Step-by-step solution →

Other 2024 papers

All CBSE Class 10 Science papers →