= Solution
The incident <photon> rate is $\dot N_\gamma=P/(hc/\lambda)\simeq2.30\times10^{15}\,\mathrm{s^{-1}}$. The stated <quantum efficiency> is $\eta=0.005$, so the emitted <electron> rate is $\eta\dot N_\gamma\simeq1.15\times10^{13}\,\mathrm{s^{-1}}$. If all emitted <electrons> are collected, the <photocurrent> magnitude is
$$
\boxed{I=e\eta\frac{P\lambda}{hc}\simeq1.84\times10^{-6}\,\mathrm A=1.84\,\mathrm{\mu A}.}
$$
The light <power> controls the number of events; the <work function> already determined the <kinetic energy> per emitted <electron> and should not be subtracted from the <photon energy> when counting incident <photons>. Incomplete collection would reduce the measured <photocurrent> below this value.
Back to article page
