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Which of the following… (Class 12 Physics SQP 2025-26, Q7)

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PhysicsCBSE Class 12 · Sample paper, session 2025-26 · 1 mark · MCQ

CBSE Class 12 Physics sample paper 2025-26: question 7

From the official CBSE sample question paper for 2025-26, section A, question 7, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q7 · 1 mark · MCQAtoms

Which of the following transitions corresponds to the emission of the radiation of the maximum wavelength?

  1. (A)I
  2. (B)III
  3. (C)IV
  4. (D)VI

Figure in the paper: Energy level diagram with levels 1, 2, 3, 4 and ∞. Transitions: I from 2 to 1 (down), II from 3 to 1... as drawn: I down from 2 to 1; II down from 3 to 2 region; III up from 3 to 4; IV down from 3 to 2; V up from 1 to 3; VI up from 2 to 3. See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.

Hints

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

Hint 1

Which arrows represent emission?

Hint 2

Wavelength is inversely proportional to the energy gap.

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. Transitions III, V and VI go upward, so they are absorptions. Only I, II and IV are emissions.

  2. Since , the longest wavelength comes from the smallest energy gap. Among the emissions, IV () has the smallest gap, so the answer is option (C).

    1 mark

Answer: Transition IV, option (C)

Where the marks are

  • Excludes the absorption transitions and picks the smallest emission gap (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Atoms, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2025-26: 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.