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The half-life of a radioactive isotope X...

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 of `1 : 7` in a sample of a given rock. The age of the rock was estimated to be.

A

60 years

B

80 years

C

100 years

D

40 years

Text Solution

Verified by Experts

The correct Answer is:
A
Value of x is `1/8=x_(0)/8=x_(0)/2^(3)implies t=3T=3xx20=60`
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