JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 25 July 2021, Shift 1, Physics Q1

Question 1 of 90 in this shift, Physics question 1 of 30, Section A.

The half-life of

^{198}\mathrm{Au}

is 3 days. If atomic weight of

^{198}\mathrm{Au}

is 198 g/mol then the activity of 2 mg of

^{198}\mathrm{Au}

is [in disintegration/second] :

(1) $16.18\times10^{12}$ Official answer
(2) $2.67\times10^{12}$
(3) $6.06\times10^{18}$
(4) $32.36\times10^{12}$

Official answer

Option 1

NTA final key.

Chapter: Nuclei
Topic: Radioactive Decay
Idea tested: Activity from Sample Mass

Same topic in other shifts

All Radioactive Decay questions

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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.