`(Bi)_212^83` can disintegrate either by emitting an `alpha` -particle or by emitting a `beta`-particle. (a) write the two equations showing the products of the decays. (b) The probabilities of disintergration by `alpha` and `beta` -decays are in the ratio 7/13. The overall half-life of `Bi^212` is one hour. If 1 g pure `Bi^212` is taken at `12.00` noon,what will be the composition of this sample at 1 p.m the same day?

Answer

A, B, C, D

Explanation

``_(83)^(212)Bi rarr _(91)^(289) T1 + _(2)^(4)He (alpha)`
``_(83)^(21)Bi rarr _(64)^(212)Bi + _(84)^(212)P_(0) + e`
`t_(1/2) = 1h, Time elapsed = 1h`
At `t = 0 , `_(212)Bi Present = 1g`
` :. At t = 1, _(212) Bi Present = 0.5 g`
Probability `alpha-decay and beta - decay` are in
ratio 7/13
`:. T/(remained) = 0.175g`
`:. P_0 remained = 0.325g.`