Atoms and Nuclei-Radioactive Decay Law (KVPY Stream SB-SX (Class 12 & 1st Year BSC) Physics): Questions 1 - 3 of 3

Get 1 year subscription: Access detailed explanations (illustrated with images and videos) to 250 questions. Access all new questions we will add tracking exam-pattern and syllabus changes. View Sample Explanation or View Features.

Rs. 200.00 or

Question number: 1

» Atoms and Nuclei » Radioactive Decay Law

Appeared in Year: 2012

MCQ▾

Question

A parent nucleus X is decaying into daughter nucleus Y which in turn decays to Z. The half-lives of X and Y are 4000 years and 20 years respectively. In a certain sample, it is found that the number of Y nuclei hardly changes with time. If the number of X nuclei in the sample is 4 × 1020, the number of Y nuclei present in it is –

Choices

Choice (4) Response
a.

2×1017

b.

4×1020

c.

2×1020

d.

4×1023

Question number: 2

» Atoms and Nuclei » Radioactive Decay Law

Appeared in Year: 2012

MCQ▾

Question

A radioactive nucleus A has a single decay mode with half-life τA. Another radioactive nucleus B has two decay modes 1 and 2. If decay mode 2 were absent, the half-life of B would have been τA2 . If decay mode 1 were absent, the half – life of B would have been 3τA . If the actual half – life of B is τB , then the ratio τBτA is –

Choices

Choice (4) Response
a.

73

b.

1

c.

37

d.

72

Question number: 3

» Atoms and Nuclei » Radioactive Decay Law

MCQ▾

Question

A parent nucleus X is decaying into daughter nucleus Y which in turn decays to Z. The half-lives of X and Y are 6000 years and 30 years respectively. In a certain sample, it is found that the number of Y nuclei hardly change with time. If the number of X nuclei in the sample is 6×1020, the number of Y nuclei present in it is –

Choices

Choice (4) Response
a.

3×1018

b.

6×1020

c.

3×1020

d.

6×1023

Sign In