Q. Monochromatic light of frequency $f$ incident on emitter having threshold frequency $f_{0}.\ $The kinetic energy of ejected electron will be
A) $hf$
B) $h(f - f_{0})$
C) $hf_{0}$
D) $h(f + f_{0})$
Explanation
(b) According to Einstein’s photo electric equation,
Incident energy = work function + kinetic energy of emitted electron
$hf\ = \ hf_{0} + K$
or $K = h(f - f_{o})$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.