Question

Which of the following graph best represents variation of photo current with respect to potential (for constant intensity)

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

+V $\to$ is anode potential
-V $\to$ is cathode potential

At some -ve potential of the anode plate, (stopping potential) the photo current is zero. No emitted electron reaches the anode plate, thereby breaking the circuit. But also photo current gradually increases upto certain +ve value after which the current saturates.
As the current varies from $0$ to saturation value, it varies non-linearly with the potential.

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


$\begin{array}{c}\text{Why this question?}\\ \text{This question combines dependence of photo electric current on anode potential with the graphical representation of it.}\end{array}$