Question

The graph shows photoelectric current with anode potential.

1. The potential at ‘O’ is called

• accelerating potential
• retarding potential
• stopping potential
• saturation potential

2. Why current becomes constant in the region BC?

3. 

Is the above graph possible? Justify your answer

Answer 1

1. Stopping potential

2. The whole electrons emitted from the cathode will reach at anode. Hence current becomes saturation at BC.

3. This graph is not possible. Stopping potential is directly proportional to frequency of incident light, ie. when frequency of incident light increases, stopping potential also increases. Hence we expect a high stopping potential for v₂.