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Photoelectric Effect and Photocell
Concepts tested here
- Photocurrent and intensity
All Questions
2006 AIPMT-PRE 1 question
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A photo-cell employs photoelectric effect to convert :-A photocell is a device that converts light energy into electrical energy using the photoelectric effect.
When light of frequency above the threshold frequency falls on the photocathode, photoelectrons are emitted and collected by the anode, giving a photoelectric current.
The number of photoelectrons emitted per second is directly proportional to the intensity of the incident light.
So a change in the intensity of illumination produces a proportional change in the photoelectric current. This is how photocells are used in light meters, automatic doors and burglar alarms.
The work function is a property of the cathode material and does not change with intensity.
A change in frequency changes the maximum kinetic energy of the photoelectrons (and the stopping potential), not the saturation current.
So a photocell converts a change in the intensity of illumination into a change in photoelectric current.