Question
Physics Question on Radioactivity
The half life of a radioactive isotope 'X' is 20 years. It decays to another element 'Y' which is stable. The two elements 'X' and 'Y' were found to be in the ratio 1 : 7 in a sample of a given rock. The age of the rock is estimated to be
A
40 years
B
60 years
C
80 years
D
100 years
Answer
60 years
Explanation
Solution
The correct option is (B): 60 years