The average lifetime for the `n = 3` excited state of a hydrogen-like atom is `4.8 xx 10^(-8) s` and that for the `n = 2 state is 12.8 xx 10^(-8) s`. The ratio of average number of revolution made in the `n = 3` sate before any transition can take place from these state is.

Explanation

No. of revolutions before transition=frequency x time Also frequency `prop(1)/(n^(3))`
So required ratio `=(((1)/(2))xx12.8xx10^(-8))/(((1)/(3))xx4.8xx10^(-8))=9`