Question

Define (i) stopping potential and (ii) threshold frequency, using Einstein’s equation and drawing necessary plot between relevant quantities.

Answer 1

Stopping potential: For a particular frequency of incident radiation, the minimum negative (retarding) potential V₀ for which the photocurrent stops or becomes zero is called the cut-off or stopping potential.

Threshold frequency: The minimum frequency required for photoelectrons to be emitted from a metal surface is called the threshold frequency.

The graph between stopping potential and frequency of incident radiation is shown below: