Question

A parallel-plate capacitor is
charged to electric
potential of 305 V by
moving 3.75 10^16
electrons from one plate to
the other. How much work
is done in charging the
capacitor?

9 J
2 J
O 0.215 J
0.915 J​

Answer 1

Given info : A parallel-plate capacitor is charged to electric potential of 305 volts by moving 3.75 × 10¹⁶ electrons from one plate to the other.

To find : How much work is done in charging the capacitor.

solution : work done to charge the capacitor , W = qV/2

where q = total charge transferred from one plate to the other

V = electric potential

here q = 3.75 × 10^16 × 1.6 × 10^-19 C [ we know charge on each electron is 1.6 × 10^-19 C]

= 6 × 10^-3 C

and V = 305 volts.

now work done , W = 1/2 qV = 6 × 10^-3 C × 305 volts

= 3 × 305 × 10^-3 J

= 0.915 J

Therefore 0.915 J work is done in charging the capacitor.