Half-lives of elements A and B are 1h and 2h respectively. Which of the following is correct?

Options

A. Element A decays slower
B. Decay constant of A is smaller
C. If initial number of nuclei are same then activity of A is more
D. Mean life of A is more

Answer

C

Explanation

Let, initial number of nuclei of each element `=N_(0)`
Decay constants `lamda_(A)=(0.693)/(1)hr^(-1),lamda_(B)=(0.693)/(2)hr^(-2)`
`lamda_(A)gtlamda_(B)`
Activities `R_(A)=lamda_(A)N_(0)`
`R_(B)=lamda_(B)N_(0)`
`impliesR_(A)gtR_(B)` as `lamda_(A)gtlamda_(B)`
Less half-life of element A implies faster decay
Mean life `tau=(1)/(lamda)`
`tau_(A)=(1)/(lamda_(A)),tau_(B)=(1)/(lamda_(B))`
`tau_(A)lttau_(B)` as `lamda_(A)gtlamda_(B)`