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Assertion (A) : In… (Class 12 Physics 2024, Q13)

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PhysicsCBSE Class 12 · Board exam 2024, set 55/1/1 · 1 mark · Assertion-reason

CBSE Class 12 Physics 2024: question 13

Set in the CBSE Class 12 board exam of 2024, paper 55/1/1, section A, question 13, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q13 · 1 mark · Assertion-reasonCompetency-basedDual Nature of Radiation and Matter

Assertion (A) : In photoelectric effect, the kinetic energy of the emitted photoelectrons increases with increase in the intensity of the incident light.
Reason (R) : Photoelectric current depends on the wavelength of the incident light.

  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 and Reason (R) is also false.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 55/1/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

What does the maximum KE of photoelectrons depend on?

Hint 2

What does the photocurrent depend on?

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. The maximum kinetic energy of photoelectrons depends on the frequency of the light, not its intensity, so A is false.

  2. The photoelectric current (above threshold) depends on intensity, not on wavelength, so R is also false. Option (D).

    1 mark

Answer: Option (D)

Where the marks are

  • States that KE depends on frequency and current on intensity, so both A and R are false (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Dual Nature of Radiation and Matter, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 55/1/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.