Question

Two elements `P` and `Q` have half-line of `10` and `15` minutes repectively. Freshly preapared sample of mixuture containing equal number of atoms is allowed to decay for `30` minutes. The ratio of number of atoms of `P` and `Q` in left in mixture is:
A. `0.5`
B. `2.0`
C. `3.0`
D. `4.0`

Answer 1

Correct Answer - `(a)`
`N_(p) = N_(OP).e^((0.693xx30)/(10)) = N_(op).e^(-0.693xx3)`
`N_(Q) = N_(oQ).e^(-(0.693xx30)/(15)) = N_(OQ).e^(-0.693xx2)`
`:. (N_(p))/(N_(Q)) = e^(-0.693) = 0.5`