- Describe briefly three experimentally observed features in the phenomenon of photoelectric effect.
- Discuss briefly how wave theory of light cannot explain these features.
CBSE OUTSIDE DELHI - SET 1 DEHRADUN 2015
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- There is no emission of photoelectrons i.e. no current if the frequency of the incident radiation is below a certain minimum value however large may be the intensity of the light.
- The current varies directly with the intensity of the incident radiation.
- The current becomes zero at a certain value of negative potential, applied at the anode , this is known as stopping potential.
- The value of stopping potential increases with the increase in the frequency of the incident radiation.
- Maximum kinetic energy of the photo electrons does not depend upon intensity of light.
- Maximum kinetic energy of photoelectron increases with the frequency of the incident radiation.
- The process of photoelectric emission is instantaneous.
- It fails to explain why:
- The photo electric emmission is instantaneous.
- There exists a threshold frequency for a given metal.
- The maximim KE of photoelectrons is independent of the intensity of incident radiation.
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