CBSE NOTES CLASS 12 PHYSICS
CHAPTER 11 DUAL NATURE OF RADIATION AND MATTER
Laws of photoelectric effect
- Effect of potential on photoelectric current
The photoelectric current increases with increase in accelerating (positive) potential. If we keep increasing the accelerating potential current reaches a maximum beyond which it does not increase. This maximum value of the photoelectric current is called saturation current.
For a particular frequency of incident radiation, the minimum negative (retarding) potential V0 for which the photocurrent stops or becomes zero is called the cut-off or stopping potential.
Maximum kinetic energy of the ejected electron,
Kmax = eV0For a given frequency of the incident radiation, the stopping potential is independent of its intensity.