Question

The charge on a capacitor plate in a circuit, as a function of time, is shown in the figure:


What is the value of current at $t=4\text{s}$?

• A. $2\mu \text{A}$
• B. $1.5\mu \text{A}$
• C. $3\mu \text{A}$
• D. Zero

Answer 1

The correct option is D Zero

$\text{Current,}I=\frac{dq}{dt}$

Clearly, from the graph, the charge is constant from $t=2\text{s}\text{to}t=6\text{s}$

$\text{Therefore,}I=\frac{dq}{dt}=0\text{at t = 4 s}$

Hence, option $\left(A\right)$ is correct.