JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyRecall

JEE Main 3 August 2021, Shift 2, Physics Q12

Question 12 of 90 in this shift, Physics question 12 of 30, Section A.

A

Z

and

M

represents the number of nucleons, protons and mass of the nucleus respectively, then mass defect

\Delta M

is represented by (

m_p

and

m_n

are mass of a proton and a neutron respectively)

(1) $\Delta M = [Am_p + (A-Z)m_n] - M$
(2) $\Delta M = [Am_p + (A-Z)m_n] - M$
(3) $\Delta M = [Zm_n + (A-Z)m_p] - M$
(4) $\Delta M = [Zm_p + (A-Z)m_n] - M$ Official answer

Official answer

Option 4

NTA final key.

Chapter: Nuclei
Topic: Nuclear Binding Energy
Idea tested: Mass Defect Calculation

Same idea in other shifts

Asked 4× in all

5 Apr 2026, Shift 2 · Q44Assuming the experimental mass of ${}^{12}_{6}\mathrm{C}$ as 12 u, the mass defect of ${}^{12}_{6}\mathrm{C}$ atom is ________…EasySingle correct
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31 Jan 2024, Shift 1 · Q60The mass defect in a particular reaction is 0.4g. The amount of energy liberated is $n\times10^7$ kWh, where $n=$ _______. (speed of light…EasyNumerical value

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.