Question

How many electrons pass through a lamp in one minute if the current is 200mA?

Answer 1

Here, current I = 300 mA = 0.3 A

   time t = 1 minute = 60 seconds

Now, charge Q = I x t = 0.3 x 60 = 18 coulomb

and no. of electrons = (total charge)/(charge on 1 electron)

    ? no. of electrons = (18)/(1.6 x 10-19)

                    = 1.125 x 1020 electrons