Answer
$6.25\times 10^{13}~electrons/s$
Work Step by Step
On the graph, we can see that the current is $10~\mu A$
We can find the number of photoelectrons which are ejected per second:
$\frac{10\times 10^{-6}~A}{1.6\times 10^{-19}~C} = 6.25\times 10^{13}~electrons/s$
