Question

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

• A. X and Y decay at same rate always
• B. X will decay faster than Y
• C. Y will decay faster than X
• D. X and Y have same decay rate initially

Answer 1

Answer: (C)

Y will decay faster than X

Answer 2

: $T_{X} = T_{Y(avg)} = 1.44T_{Y}$

i.e. $T_{X} > T_{Y}\therefore\lambda_{X} < \lambda_{Y}$

$\because$R $= \lambda$ N and N is same for both

$\therefore R_{X} < R_{Y}orR_{Y} > R_{X}$

i.e. Y will decay faster than X