Answer
There are $~~3.1\times 10^{11}~electrons~~$ per pulse.
Work Step by Step
We can find the number of electrons per pulse:
$\frac{(0.50~A)(0.10\times 10^{-6}~s)}{1.6\times 10^{-19}~C/electron} = 3.1\times 10^{11}~electrons$
There are $~~3.1\times 10^{11}~electrons~~$ per pulse.
