When using a constant current to charge the capacitor, the charging voltage on the capacitor will follow the equation:

Q=Idt=CV

If we know the input in terms of number of electrons, we can use the equation to calculate the current:

Formula :

Number of electrons ( N ) = ( I x t ) / e

Where,

I is the reading of ammeter.

t is the amount of time the current flows.

e is the charge of one electron.

e = 1.6 x 10 ^ ( -19 )

Given:

I = 0.50 A

t = 2.0 min = 1.2×102 s

I=q/t, so the magnitude of the charge is

q = It = (0.50A)(1.2×102 s) = (0.50C/s)(1.2×102 s) = 60 C

Solving for number of electrons from

q = ne

n = q/e = 60 C/1.6×10-19 C/electrons = 3.8×1020 electrons

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