Question

A point source of light is used in an experiment on photoelectric effect. Which of the following curves best represents the variation of photo current $\left(i\right)$ with distance $\left(d\right)$ of the source from the emitter

• A. $c$
• B. $d$
• C. $a$
• D. $b$

Answer 1

The correct option is B $d$

Photocurrent $\left(i\right)$ is directly proportional to intensity $\left(I\right)$
$i\propto I$
Intensity $\left(I\right)$ is inversely proportional to the square of the distance.
$I\propto \frac{1}{d^2}$
$i\propto I$
$i\propto \frac{1}{d^2}$

Hence the correct option is (d).