A photon of energy hv is absorbed by a free electron of a metal having work function ϕ<hv
A photon of energy hv is absorbed by a free electron of a metal having work function ϕ<hv
The correct option is D It may come out with a kinetic energy less than hv – φ.
As was hinted, providing an energy greater the work function does not ensure that the electron will be ejected from the surface. It may –
1. Lose all its energy in internal collisions and not come out , even when it received an energy E > W
2. Lose some of its energy in collisions but still come out with an energy less than the maximum possible
kinetic energy, K.E<K.Emax
3. Not lose energy at all, and come out with the maximum kinetic energy possible, given by Einstein's
photoelectric equation K.Emax=E−W
In the options given in the question, (a) and (b) can’t be right due to point no. 1 above. Point no. 2 makes sure option (c) is also not correct.
The statement "it may come out with a kinetic energy less than(hv−ϕ)′′ is not wrong, as it doesn’t violate any of the above points. Hence, (d) is the correct answer.
It may come out with a kinetic energy less than hv – φ.
As was hinted, providing an energy greater the work function does not ensure that the electron will be ejected from the surface. It may –
1. Lose all its energy in internal collisions and not come out , even when it received an energy E > W
2. Lose some of its energy in collisions but still come out with an energy less than the maximum possible
kinetic energy, K.E<K.Emax
3. Not lose energy at all, and come out with the maximum kinetic energy possible, given by Einstein's
photoelectric equation K.Emax=E−W
In the options given in the question, (a) and (b) can’t be right due to point no. 1 above. Point no. 2 makes sure option (c) is also not correct.
The statement "it may come out with a kinetic energy less than(hv−ϕ)′′ is not wrong, as it doesn’t violate any of the above points. Hence, (d) is the correct answer.
