Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Dual Nature of Radiation and Matter

Question:

The cathode of a photoelectric cell is changed such that the work function changes from W1 to W2 (W2 > W1). If the currents before and after change are I1 and I2, all other conditions unchanged, then (assuming hf> W2)

Options:

I1 = I2   

I1 < I2

I1 > I2    

 I1 < I2 < 2I1

Correct Answer:

I1 = I2   

Explanation:

As long as Energy of photon hf> W(Work Function), photoelectron will be emitted i.e the work function has no effect on the current. So, work function does not play any role here. Further, the photo-electric current is proportional to intensity of light. Here, there is no change in the intensity of light. Hence I1 = I­2.