Question

Disintegration constant of a radioactive material is `lambda`:
A. Its half life equal to `(log_(e)2)/(lambda)`
B. It mean life equals to `(1)/(lambda)`
C. At time equal to mean life, `63%` of the Initial radioactive material is left undecayed
D. After `3-` half 1/3 rd of the initial radioactive material is left undecayed.

Answer 1

Correct Answer - A::B
`N = N_(0)e^(-lambdat) rArr (N_(0))/(10) = N_(0)e^(-lambdaT_(1//2))`
`rArr T_(1//2) = (log_(e)2)/(lambda) rArr T_(mean) = (1)/(lambda)`