Answer
The average power is $~~1240~W$
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.
We can find the average power:
$P = (3.1\times 10^{11}~electrons)(50\times 10^6~eV/electron)(\frac{1.6\times 10^{-19}~J}{1~eV})(500~s^{-1})$
$P = 1240~W$
The average power is $~~1240~W$
