question_answer

The half-life period of a radioactive element X is same as the mean life time of another radioactive element Y. Initially, they have the same number of atoms. Then,                                       [AIEEE 2007]

A) X will decay faster than Y

B) Y will decay faster than X

C) Y and X have same decay rate initially

D) X and Y decay at same rate always

Correct Answer: B

Solution :

[b] The half-life for element X

where,is mean life of element Y.

So, Y will decay faster than X.

(is decay constant)