Question

A varying voltage is applied between the terminals $A,B$ so that the voltage across the capacitor varies as shown in the figure. Then

• A. The voltage between the terminals $CD$ is constant between $2t_0$ and $3t_0$
• B. The current in the resistor is $0$ between $2t_0$ and $3t_0$
• C. The average current in the resistor between $t_0$ and $5t_0$ is zero
• D. The current in the resistor between $t_0$ and $2t_0$ is twice the current between $3t_0$ and $5t_0$

Answer 1

Answer: (B), (C), (D)

The correct options are
B The current in the resistor is $0$ between $2t_0$ and $3t_0$
C The average current in the resistor between $t_0$ and $5t_0$ is zero
D The current in the resistor between $t_0$ and $2t_0$ is twice the current between $3t_0$ and $5t_0$

When the capacitor voltage is constant, its charge is constant. Hence, no current flows in the resistor. Also $\frac{dq}{dt}$ is double between $t_0$ and $2t_0$ compared to $3t_0$ and $5t_0$ since the slope of V-t is double.