When the incident light's frequency is increased, the KE of the electron increases which means their velocity increases (as mass is constant). So, shouldn't the photo-current increase as the rate of flow of electron increases (number of electrons remains same but the time taken by them to go around the circuit decreases)?

Asked by Maharnab Mitra | 14th Oct, 2013, 01:58: PM

Expert Answer:

Velocity of emitted electrons depend upon their Kinetic energy as given by

K.E. = ½ mv2 or v =?(2KE/m).

But the K.E. of electrons are independent of the intensity of incident light.

If intensity is increased photo current will increase that means number of electrons ejected will increase.

This increase in photo current will be directly proportional to the intensity of the incident light.

But the incident light must be above the threshold frequency for the given material otherwise no electrons will be emitted however strong will be the intensity of the incident light.

Answered by Faiza Lambe | 14th Oct, 2013, 03:01: PM

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