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Saturday, 31 October

JEE Main 2023 · PhysicsMultiple choiceSingle correctEasyApplication

JEE Main 11 April 2023, Shift 1, Physics Q33

Question 33 of 90 in this shift, Physics question 3 of 30, Section A.

Two radioactive elements A and B initially have same number of atoms. The half life of A is same as the average life of B. If λA\lambda_A and λB\lambda_B are decay constants of A and B respectively, then choose the correct relation from the given options.
  1. (1)λAln⁡2=λB\lambda_A \ln 2 = \lambda_B
  2. (2)λA=λBln⁡2\lambda_A = \lambda_B \ln 2Official answer
  3. (3)λA=λB\lambda_A = \lambda_B
  4. (4)λA=2λB\lambda_A = 2\lambda_B

Official answer

Option 2

NTA final key.

Chapter
Nuclei
Topic
Radioactive Decay
Idea tested
Mean Life Calculation

Same idea in other shifts

Asked 2× in all
  1. 26 Feb 2021, Shift 2 · Q1A radioactive sample is undergoing α\alpha decay. At any time t1t_1, its activity is A and another time t2t_2, the activity is…EasySingle correct

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 108 of the 174 JEE Main shifts held from 2017 to 2026.