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