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Question : 6
Total: 9
Explain giving reasons for the following:
(a) Photoelectric current in a photocell increases with the increase in the intensity of the incident radiation.
(b) The stopping potential( V 0 )
(c) Maximum kinetic energy of the photoelectrons is independent of the intensity of incident radiation.
(a) Photoelectric current in a photocell increases with the increase in the intensity of the incident radiation.
(b) The stopping potential
(c) Maximum kinetic energy of the photoelectrons is independent of the intensity of incident radiation.
Solution:
(a) Variation of photocurrent with intensity of radiation
(b) Stopping potential versus frequency for different materials
(c) Independence of maximum kinetic energy of the emitted photoelectrons
(a) The collision of a photon can cause emission of a photoelectron (above the threshold frequency). As intensity increases, number of photons increases. Hence the current increases.
(b) We have,e V s = h ( v − v 0 )
∴ V s =
( v ) + ( −
)
∴ Graph ofV s v ( = h ∕ e )
(c) Maximum for different surfacesKE = h ( v − v 0 )
Hence, it depends on the frequency and not on the intensity of the incident radiation.
(b) Stopping potential versus frequency for different materials
(c) Independence of maximum kinetic energy of the emitted photoelectrons
(a) The collision of a photon can cause emission of a photoelectron (above the threshold frequency). As intensity increases, number of photons increases. Hence the current increases.
(b) We have,
∴ Graph of
(c) Maximum for different surfaces
Hence, it depends on the frequency and not on the intensity of the incident radiation.
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