Question

A Capacitor is a circuit component that stores energy and can be charged when current flows through it. A current of 3A flows through a capacitor that has an initial charge of 2μC (micro Coulombs). After two microseconds, how much is the magnitude of the net electric charge (in μC) of the capacitor?

Answer 1

8 μC

Step-by-step explanation:

By definition, current is the rate of change of charge, so we can write the following equation for current I:

I = ΔQ / Δt

As charge must be conserved, all the charge carried by the current must add to the charge on the plates of the capacitor, so we can finf this incremental charge as follows:

ΔQ = I* Δt (assuming that current remains constant during the charging process)

⇒ ΔQ = 3 A* 2 μsec = 3 coul/sec*2 μsec = 6 μC

As the initial charge must be conserved also, the magnitude of the net electric charge of the capacitor must be as follows:

Qnet = Q₀+ ΔQ = 2 μC + 6 μC = 8 μC