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प्रश्न
A beam of monochromatic radiation is incident on a photosensitive surface. Answer the following question giving reason :
Does the kinetic energy of the emitted electrons depend on the intensity of incident radiation?
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उत्तर
No, the kinetic energy of the emitted electrons does not depend on the intensity of incident radiation. If the intensity of the incident light radiation is increased, then the number of incident photons falling per second on the metal surface also increases but the energy of each photon remains the same as the frequency of the radiation is not changing. The maximum kinetic energy of a photoelectron depends only on the frequency of incident radiation and not on the intensity of incident radiation.
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संबंधित प्रश्न
Sketch the graphs showing variation of stopping potential with frequency of incident radiations for two photosensitive materials A and B having threshold frequencies vA > vB.
(i) In which case is the stopping potential more and why?
(ii) Does the slope of the graph depend on the nature of the material used? Explain.
The photoelectric work function for a metal is 4.2 eV. If the stopping potential is 3V, find the threshold wavelength and maximum kinetic energy of emitted electrons.
(Velocity of light in air = 3 x 108m/s,
Planck's constant = 6·63 x10-34 J -s,
Charg.e ori electron = 1·6 x 10 -19 C)
Draw a plot showing the variation of photoelectric current versus the intensity of incident radiation on a given photosensitive surface.
The work functions for potassium and caesium are 2.25 eV and 2.14 eV respectively. Is the photoelectric effect possible for either of them if the incident wavelength is 5180 Å?
[Given : Planck’s constant = 6.63 x 10–34 J.s.;
Velocity of light = 3 x 108 m/s; 1 eV = 1.6 x 10–19 J]
What is photoelectri effect ? Defin (i) Stopping potential (ii) Photoelectric work function.
Plot a labelled graph of IVsl where Vs is stopping potential versus frequency f of the incident radiation.
State how will you use this graph to detennine the value of Planck's constant.
If the frequency of the incident radiation is increased from 4 × 1015 Hz to 8 × 1015 Hz, by how much will the stopping potential for a given photosensitive surface go up?
Light of wavelength 4000 Å is incident on two metals A and B. Which metal will emit photoelectrons, if their work functions are 3.8 e V and 1.6 e V respectively?
The phenomenon of photoelectric emission was observed by ______.
