In a p-n junction photo cell, the value of the photo-electromotive force produced by monochromatic light is proportional to (a) The barrier voltage at the p-n junction. (b) The intensity of the light falling on the cell. (c) The frequency of the light falling on the cell. (d) The voltage applied at the p-n junction.

Answer: (b). In a photocell, each absorbed photon (with hν > Eg) creates an electron-hole pair that is separated by the junction field. More intensity means more photons per second, more pairs, and so a larger photo-emf. Frequency above the threshold does not increase the number of pairs. So the answer is (b) the intensity of the light falling on the cell.

In a p-n junction photo cell, the value of the photo-electromotive… | NEET 2004 (AIPMT)

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Special Purpose Diodes

In a p-n junction photo cell, the value of the photo-electromotive force produced by monochromatic light is proportional to

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Answer: (b)

In a photocell, each absorbed photon (with $h\nu > E_g$ ) creates an electron-hole pair that is separated by the junction field.
More intensity means more photons per second, more pairs, and so a larger photo-emf.
Frequency above the threshold does not increase the number of pairs.
So the answer is (b) the intensity of the light falling on the cell.

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