Question

Which one of the following graphs represent the variation of maximum kinetic energy of photo electrons emitted from a photoemitter with frequency? 

(1) A 

(2) B 

(3) C

(4) D

Answer 1

Correct option :  (2)

Explanation :

Einstein’s photoelectric equation is 1/2 mv²_max = hv - ω₀ 

This is of the form y = mx, the equation of a straight line with a negative y intercept t and slope h. To come out from a photo emitter a electron needs energy equal to the work function of the emitter and gets this energy from the energy hv of the photons incident on the emitter. When the frequency of the incident photons is decreased the energy of the incident photons also decreases as ω₀ is a constant.