Consider the direct photoreaction of fictitious compound $BC,$ which has a mixing ratio of $100$

ppbv and an average absorption coefficient between $300$ and $340nm$ of $3\mathrm{.}0{10}^{-19}c{m}^{2}ml{c}^{-1}$

$($and no absorption at longer wavelengths$).$ The excited state of $BC$ has three fates: $($i$)$

fluorescence $($to yield $BC$ and a photon$),($ii$)$ reaction to make $B$ and $C($i$.$e$.,$ separate atoms$),$ and

$($iii$)$ reaction to make $BC{O}_2.$ Quantum yields for these paths are $0\mathrm{.}50,0\mathrm{.}35,$ and $0\mathrm{.}15,$

respectively.

a$.$ If the total actinic flux between $300$ and $340nm$ is $1\mathrm{.}5{10}^{14}$ photons $c{m}^{-2}{s}^{-1},$ what is the

photochemical lifetime of $BC?$

b$.$ What is the rate of photochemical loss of $BC?$

c$.$ What is the rate of formation of $BC{O}_2?$