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The variation of the stopping… (Class 12 Physics 2024, Q8)

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PhysicsCBSE Class 12 · Board exam 2024, set 55/5/1 · 1 mark · MCQ

CBSE Class 12 Physics 2024: question 8

Set in the CBSE Class 12 board exam of 2024, paper 55/5/1, section A, question 8, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q8 · 1 mark · MCQDual Nature of Radiation and Matter

The variation of the stopping potential () with the frequency () of the incident radiation for four metals A, B, C and D is shown in the figure. For the same frequency of incident radiation producing photo-electrons in all metals, the kinetic energy of photo-electrons will be maximum for metal

  1. (A)A
  2. (B)B
  3. (C)C
  4. (D)D

Figure in the paper: Graph of V0 (vertical axis) versus frequency v (horizontal axis) with four parallel straight lines labelled A, B, C, D, each with positive slope, starting at increasing frequency intercepts on the v-axis from A (smallest intercept) to D (largest intercept). See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 55/5/1.

Hints

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

Hint 1

The intercept on the frequency axis is the threshold frequency.

Hint 2

Use Einstein's equation .

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. . For the same , is largest for the smallest threshold frequency .

    ½ mark

  2. Metal A has the smallest intercept on the -axis, so its photoelectrons have maximum KE. Option (A).

    ½ mark

Answer: Metal A, option (A)

Where the marks are

  • Relates max KE to lowest threshold frequency, picks A (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 55/5/1: 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.