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A photo-cell employs photoelectric effect to convert:

1. a change in the intensity of illumination into a change in photoelectric current
2. a change in the intensity of illumination into a change in the work function of the photocathode
3. a change in the frequency of light into a change in the electric current
4. a change in the frequency of light into a change in electric voltage

Correct answer: a change in the intensity of illumination into a change in photoelectric current

Solution

A photo-cell works on the principle of the photoelectric effect, where the intensity of illumination determines the number of photoelectrons emitted, which in turn affects the photoelectric current.

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