JEE Main 2020PhysicsNuclear PhysicsMediumMCQ

JEE Main 2020 — Nuclear Physics Question with Solution

JEE Main 2020 (07 Jan Shift 2)

Question

The activity of a radioactive sample falls from 700s-1 to 500s-1 in 30 minutes. Its half life is close to:

Choose an option

Show full solutionCorrect option: B
Correct answer
B62min

Step-by-step explanation

From equation of radioactivity. At=A0e-λt

         lnA0At=λt

⇒  ln700500=λ(30min) ------1

also

⇒  ln2=λt1/2 --------2

(ii)/(i)

⇒  ln2ln(7/5)=t1/2(30min)  ⇒  (2.06004)30=t1/2=61.8min

≈      62min

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About this question

This is a previous-year question from JEE Main 2020, 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.