The fluorescence lifetime of a molecule in a solution is $5 \times 10^{-9} \mathrm{s}$. The sum of all the noradiative rate constants ( $\Sigma \mathrm{k}_{\mathrm{nr}}$ ) for the decay of excited state is $1.2 \times 10^{8} \mathrm{s}^{-1}$. The fluorescence quantum yield of the molecule is
(a)0.1
(b)0.2
(c)0.4
(d)0.6
Answer
Answer: C ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.