Assertion:The photoelectrons produced by monochromatic light beam incident on a metal surface,have spread in their kinetic energy
Reason: The work function of the metal varies as a function of depth from the surface
If both assertion and reason are true and the reason is the correct explanation of assertion
If both assertion and reason are true and the reason is not the correct explanation of assertion
If assertion is true but reason is false
If assertion is false but reason is true
Electrons being emitted as photoelectrons have different velocities. Actually, all the electrons do not occupy the same level of energy but they occupy continuous bands and levels.so, electrons being knocked off from different levels come out with different energies. The work function is the energy required to pull the electron out of the metal surface. Naturally, electrons on the surface will require less energy to be pulled out and hence will have lesser work function as compared with those deep inside the metal. So assertion and reason are correct and reason correctly explains the assertion.