Q. The collector plate in an experiment on photoelectric effect is kept vertically above the emitter plate. Light source is put on and a saturation photo current is recorded. An electric field is switched on which has a vertically downward direction
A) The photo current will increase
B) The kinetic energy of the electrons will increase
C) The stopping potential will decrease
D) The threshold wavelength will increase
Explanation
(b) In electric field photoelectron will experience force and accelerate opposite to the field so it’s $K.E.$ increases ($i.e.,$ stopping potential will increase), no change in photoelectric current, and threshold wavelength
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.