## Answers

If energy of photon = E (= hν) work function of metallic surface = ϕ = (hν0)

kinetic energy of emitted electron = 12mv2

E = ϕ+1/2mv^2

1/2mv^2=h(v−v0)

Einstein's equation

Two charactristics of photons

(i) This equation is based on particle nature of light

(ii) Total energy of photon is transffered completly to single electron.

(iii) If incident frequency ν < threshold frequency (ν0), then kinetic energy (12mv2) will be negative which is not possible because kinetic energy can not be negative. This shows that photoelectric emission is not possible if frequency (v) of incident light is less than the threshold frequency (v0) of the metal.

(iv) One photon can emit only one electron from the metal surface, so the number of photoelectrons emitted

per second is directly proportional to the intensity of incident light which depends upon number of photons present in the incident light.

(v) From eqn. it is clear that kinetic energy,12mv2 increases with the increase in the frequency (v) of the incident light.