JEE Main 2021PhysicsNuclear PhysicsHardMCQ

JEE Main 2021 — Nuclear Physics Question with Solution

JEE Main 2021 (20 Jul Shift 1)

Question

A nucleus of mass M emits γ-ray photon of frequency v. The loss of internal energy by the nucleus is: [Take c as the speed of electromagnetic wave]

Choose an option

Show full solutionCorrect option: D
Correct answer
Dhv1+hv2Mc2

Step-by-step explanation

Energy of γ ray Eγ=hv

Momentum of γ ray Pγ=hλ=hvc
Total momentum is conserved.

P→γ+P→Nu=0
where P→Nu= momentum of decayed nuclei

⇒Pγ=PNu
⇒hvc=PNu
⇒KE of nuclei

=12Mv2=PNu22M=12Mhvc2
Loss in internal energy =Eγ+KENu
=hv+12Mhvc2
=hv1+hv2Mc2

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About this question

This is a previous-year question from JEE Main 2021, covering the Nuclear Physics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.