Nuclei

JEE Main 2025 (Online) 23rd January Morning ShiftMCQEasy📈 Topic in 5% papers+4−1

Ques. 1JEE Main 2025, 23 January (Morning Shift)

A radioactive nucleus n2 has 3 times the decay constant as compared to the decay constant of another radioactive nucleus n1. If initial number of both nuclei are the same, what is the ratio of number of nuclei of n2 to the number of nuclei of n1, after one half-life of n1 ?

Answer

(1) 1/4

Solution

N=N0e- t. In one half-life of n1: n1 halves; n2 ( 2=3 1) goes through 3 half-lives.

[figure]

N1= N02, N2= N023= N08

N2N1= 1/81/2= 14

Answer: (1)

Keep practising — Nuclei

Ques. 2JEE Main 2025, 23 January (Evening Shift)

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the correct answer from the options given below :

(A) is true but (R) is false
Both (A) and (R) are true and (R) is the correct explanation of (A)
(A) is false but (R) is true
Both (A) and (R) are true but (R) is NOT the correct explanation of (A)

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