Question
Define the terms threshold frequency and stopping potential in relation to the phenomenon of photoelectric effect. How is the photoelectric current affected on increasing the (1) frequency (2) intensity of the incident radiations and why?
✓
Answer
- Threshold frequency:
The minimum frequency of the incident radiation for a given metal below which emission of photo electrons does not take place.
- Stopping potential:
The minimum negative potential of the anode collector for which photoelectric current becomes zero.
- (1) (Practically) No effect/remain same.
As increase in frequency does not significantly change the number of photons in the beam.
(2) Increases:
The number of incident photons increases.
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