Question
Physics Question on Nuclei
A radio isotope 'X' with a half life 1.4 × 109 years decays to 'Y' which is stable. A sample of the rock from a cave was found to contain 'X' and 'Y' in the ratio 1:7. The age of the rock is:
A
3.92 × 109 years
B
4.20 × 109 years
C
8.40 × 109 years
D
1.96 × 109 years
Answer
4.20 × 109 years
Explanation
Solution
The correct option (B): 4.20 × 109 years