Question

two monochromatic radiations blue and violet of the same intensity are incident on a photosensitive surface cause photoelectric emission.Would (1)the no. of electrons emitted per sec and(2) the maximum kinetic energy of the electrons be equal in the two cases? justify

Answer 1

the number of electrons emitted per sec and the maximum kinetic energy of the electrons be equal in two cases.

Answer 2

(1) The number of electrons emitted per sec will be equal in both cases.

• The reason is that the number of electrons emitted is directly proportional to the intensity and since it is given that intensities of both the radiations are the same.

• Thus, In both cases, the number of electrons emitted per sec will also be the same.

(2) The maximum kinetic energy of the electrons will not be equal in the two cases.

• Blue light has a frequency range of 450–495 nm and violet light has a frequency range of 380–450 nm. And it can be seen that blue light has more frequency than violet.

• And, also kinetic energy = hν

• Thus, the kinetic energy of the electrons will be more in case of blue light in comparison to violet light.