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Nuclei — NEET & JEE Physics MCQs

30 questions written by hand against the NCERT chapter. Every wrong option is explained, not just the right one.

30questions
10/14/6easy / medium / hard
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Sample questions from this chapter

The unified atomic mass unit, denoted by u, is defined as what fraction of the mass of a carbon-12 atom?
  1. One-twelfth ✓
  2. One-sixth
  3. One-fourteenth
  4. One-sixteenth
Answer: A. By definition, 1 u is exactly one-twelfth of the mass of one neutral carbon-12 atom in its ground state.
Why not B: One-sixth is twice the defined fraction and would not reproduce the standard atomic-mass scale.
Why not C: One-fourteenth incorrectly uses nitrogen's mass number instead of the carbon-12 reference standard.
Why not D: One-sixteenth resembles an oxygen-based scale but is not the modern definition of the unified unit.
A gold-197 nucleus has atomic number 79. How many neutrons does it contain?
  1. 79
  2. 197
  3. 118 ✓
  4. 276
Answer: C. Using N = A - Z gives N = 197 - 79 = 118 neutrons.
Why not A: Seventy-nine is the proton count Z; the neutron count requires subtracting Z from A.
Why not B: One hundred ninety-seven counts all nucleons and therefore includes both protons and neutrons.
Why not D: Adding A and Z double-counts the protons instead of isolating the neutron population.
Using R = R0 A^(1/3), what is the approximate ratio of the radius of gold-197 to that of silver-107?
  1. 1.23 ✓
  2. 1.84
  3. 0.54
  4. 3.39
Answer: A. The ratio is (197/107)^(1/3), which is approximately 1.23; the constant R0 cancels.
Why not B: This is close to the direct mass-number ratio, but radius depends on its cube root.
Why not C: This inverse mass-number ratio would also predict the heavier gold nucleus to be smaller.
Why not D: This resembles an incorrectly amplified power dependence rather than the cube-root scaling law.

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Every NCERT question in this chapter is solved, free: NCERT solutions — Nuclei →

Other NEET Physics chapters

Units and MeasurementMotion in a Straight LineMotion in a PlaneLaws of MotionWork Energy and PowerSystems of Particles and Rotational Motion

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Questions

How many NEET and JEE questions are there on Nuclei?

This chapter test has 30 questions — 10 easy, 14 medium and 6 hard — all written against the NCERT Class 12 chapter.

Is this NEET and JEE Physics chapter test free?

Yes. Every chapter test is free with no login, and you get your all-India rank on every one. Nothing on the site is on sale right now.

Do the questions explain the wrong options?

Yes — every distractor carries its own explanation naming the specific misconception that makes a student pick it. That is the part most question banks skip, and it is the part that changes your next attempt.