What is the effect on the maximum kinetic energy and the number of photoelectrons when (i) The intensity of incident light decreases. (ii) The emitting surcac is charged. (iii) Wavelength of incident light increase.

Answer

(i) Number of electrono ejected from the surface will decrease and no effect on kinetic energy of electron.
(ii) No effect on number of electrons but kinetic energy will change.
(iii) Kinetic energy will decrease and no effect on number of photo electrons.

Explanation

`KE_(max)=hv-phi`, Also `E_("photo/time")=(Nhc)/(lambda)`
(i) When intensity of light is light is decreased number of botons decreases but `KE_(max)` remains same.
When emitting surface is charged, `phi` changes. So `KL_(max)` changes. If emitter is changed then +ve no. of photoelectros becomes zero.
(iii) Increasing `lambda, [(hc)/lambda-phi]darr`