Concepts Of Physics MCQ Edition [Volume 2]PhysicsPhotoelectric Effect and Wave–Particle Duality
A photon of energy h is absorbed by a free electron of a metal with a work function < h .
Options
- AThe electron either does not emerge or it emerges with a kinetic energy of h - .
- BThe electron is certain to be emitted.
- CThe electron may emerge with a kinetic energy less than h - .
- DThe electron is certain to be emitted with a kinetic energy of h - .
Correct answer
C. The electron may emerge with a kinetic energy less than h - .
Step-by-step solution
According to Einstein's photoelectric equation, the maximum kinetic energy of an emitted photoelectron is given by K_ = h - . This maximum kinetic energy corresponds to the electrons emitted from the surface without suffering any collisions. However, when a photon is absorbed by an electron deeper inside the metal, the electron may suffer collisions with other atoms or electrons before reaching the surface, thereby losing a part of its energy. As a result, the kinetic energy of the emitted electron can be any value