JEE Main 2023PhysicsNuclear PhysicsMediumMCQ

JEE Main 2023 — Nuclear Physics Question with Solution

JEE Main 2023 (29 Jan Shift 2)

Question

Substance A has atomic mass number 16 and half life of 1 day. Another substance B has atomic mass number 32 and half life of 12 day. If both A and B simultaneously start undergo radio activity at the same time with initial mass 320 g each, how many total atoms of A and B combined would be left after 2 days

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Show full solutionCorrect option: A
Correct answer
A3.38 × 1024

Step-by-step explanation

Number of nuclei left after n half-lives is given by,

N=N012tt12.

As, N0A=32016=20 moles and 

N0B=32032=10 moles

Then, NA=N0A221=204=5 and 

NB=N0B220.5=1024=0.625

So total N = 5.625

 and number of atoms =5.625×6.023×1023

=3.38×1024

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About this question

This is a previous-year question from JEE Main 2023, 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.