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The mass density of a nucleus… (Class 12 Physics 2023, Q12)

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PhysicsCBSE Class 12 · Board exam 2023, set 55/1/1 · 1 mark · MCQ

CBSE Class 12 Physics 2023: question 12

Set in the CBSE Class 12 board exam of 2023, paper 55/1/1, section A, question 12, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q12 · 1 mark · MCQNuclei

The mass density of a nucleus of mass number A is :

  1. (A)proportional to
  2. (B)proportional to
  3. (C)proportional to
  4. (D)independent of A

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 55/1/1.

Hints

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

Hint 1

How does the nuclear radius depend on A?

Hint 2

Volume is proportional to .

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 nuclear radius is , so the volume is proportional to . The mass is also proportional to .

    ½ mark

  2. Density = mass/volume, so cancels and the density is independent of . This is option (D).

    ½ mark

Answer: Independent of A, option (D)

Where the marks are

  • Uses to show density is independent of A (1 mark)

Revise the chapter

  • Chapter: Nuclei (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Nuclei, one at a time, marked against the answer key and marking points.Back to the full paper2023 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.