- A photoelectric cell is illuminated by monochromatic light of frequency v. The graph of the stopping potential V versus the frequency v of the incident light is as shown in the figure. The work function of the material is:
(A) h v (B) h/v (C) h/2v (D) h/4v
The correct answer is: (B) h/v
The work function of the material is the minimum energy required to remove an electron from the metal. The stopping potential is the minimum potential required to stop the electrons from reaching the collector. The graph of the stopping potential versus the frequency of the incident light is a straight line with a negative slope. The slope of the graph is equal to the Planck’s constant divided by the charge of an electron.
- In a photoelectric experiment, the wavelength of the incident light is changed from 400 nm to 200 nm. The change in the stopping potential will be:
(A) 2 eV (B) 4 eV (C) 6 eV (D) 8 eV
The correct answer is: (C) 6 eV
The stopping potential
