Answer:
600 mC
Step-by-step explanation:
The charge of an electron is 1.6 x 10-19C so for a current with 10 mA, the charge going to screen in one second is 10 mC
so number of electrons, n = (10 x 10-3)/(1.6 x 10-19) = 6.25 x 1016 so in a minute the charge is 10 * 60 = 600 mC