JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyApplication

JEE Main 16 March 2021, Shift 2, Physics Q10

Question 10 of 90 in this shift, Physics question 10 of 30, Section A.

Calculate the time interval between 33% decay and 67% decay if half-life of a substance is 20 minutes.

(1)20 minutesOfficial answer
(2)40 minutes
(3)60 minutes
(4)13 minutes

Official answer

Option 1

NTA final key.

Chapter: Nuclei
Topic: Radioactive Decay
Idea tested: Half-Life Calculations

Same idea in other shifts

Asked 5× in all

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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.