Target Exam

CUET

Subject

Physics

Chapter

Dual Nature of Radiation and Matter

Question:

The figure shows a plot of photocurrent versus anode potential for a photosensitive surface for three different radiations. Which one of the following is a correct statement?

Options:

Curves a and b represent incident radiations of different frequencies and different intensities

Curves a and b represent incident radiations of same frequency but of different intensities

Curves b and c represent incident radiations of different frequencies and different intensities

Curves b and c represent incident radiations of same frequency having same intensity

Correct Answer:

Curves a and b represent incident radiations of same frequency but of different intensities

Explanation:

The energy of the incident photon is hν.


Hence frequency determines the energy of incident photons. This energy is imparted on the photosensitive surface to cause photo ejection. At the points where curve cuts the x axis, the incident photon energy is equal to the work potential of material. Hence energy, hence frequency, is same for radiation of curves a & b.
 
Intensity is the measure of number of photons striking per unit time. Thus they determine the amount of photocurrent produced. Thus it is same for b & c.