A photoelectric cell is fitted with an adjustable anode–cathode voltage source
PHYSICS · Multi-part · CBSE · Physics · Dual Nature of Radiation and Matter · Dual Nature of Radiation and Matter
Problem
A photoelectric cell is fitted with an adjustable anode–cathode voltage source. Light of frequency 8.0×1014Hz is incident on a metal cathode whose work function is 3.2eV.
(i) Calculate the minimum negative potential that must be applied to the anode to just stop the photo-current.
(ii) If the applied potential in part (i) is kept fixed and the frequency of light is gradually decreased, find the frequency at which the photo-current will just cease.
(iii) By what factor will the number of photo-electrons emitted per second change if, keeping the frequency at 8.0×1014Hz, the intensity of light is made four times larger? Comment on the stopping potential in this situation.