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 consist of A is smaller.
C. If initial number of nuclei are same, than activity of A is more
D. Mean-life of A is more

Answer

C

Explanation

Let initial numberof nuclei of each element `=N_(0)`
Decay constants, `lambda_(A) = (0.693)/1 h^(-1)`, `lambda_(B) = (0.693)/2 h^(-2)`
`lambda_(A) gt lambda_(B)`
Activities, `R_(A) = lambda_(A) gt lambda_(B)`
`R_(B) = lambda_(B)N_(0)`
`rArr R_(A) gt R_(B)` as `lambda_(A)gtlambda_(B)`
less half-life of element A implies faster decay.
Mean-life, `rho=1/lambda`
`rho_(A) = 1/lambda_(A)`, `rho_(B)= 1/lambda_(B)`
`rho_(A) lt rho_(B)` as `lambda_(A) gt lambda_(B)`