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प्रश्न
Briefly explain the three observed features which can be explained by Einstein’s photoelectric equation.
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उत्तर
Three observed features which can be explained by this equation are:
(i) Solar cells: Also called photo-voltaic cells. It converts solar radiations to electrical emf.
(ii) Television telecast: The dark and bright light part of images are interpreted as high and low electrical charges as given by photoelectric emission principle. These are further processed and transmitted.
(iii) Burglar alarm: The moment the ultraviolet radiation is cut due to theif, it stops the supply of photons and thus works as ‘off’ mode and the ring bells automatically.
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संबंधित प्रश्न
Light of wavelength 488 nm is produced by an argon laser which is used in the photoelectric effect. When light from this spectral line is incident on the emitter, the stopping (cut-off) potential of photoelectrons is 0.38 V. Find the work function of the material from which the emitter is made.
Plot a graph showing the variation of photoelectric current with collector plate potential at a given frequency but for two different intensities I1 and I2, where I2 > I1.
Use Einstein's photoelectric equation to show how from this graph,
(i) Threshold frequency, and
(ii) Planck's constant can be determined.
- In the explanation of photo electric effect, we assume one photon of frequency ν collides with an electron and transfers its energy. This leads to the equation for the maximum energy Emax of the emitted electron as Emax = hν – φ0 where φ0 is the work function of the metal. If an electron absorbs 2 photons (each of frequency ν) what will be the maximum energy for the emitted electron?
- Why is this fact (two photon absorption) not taken into consideration in our discussion of the stopping potential?
A student performs an experiment on photoelectric effect, using two materials A and B. A plot of Vstop vs ν is given in Figure.
- Which material A or B has a higher work function?
- Given the electric charge of an electron = 1.6 × 10–19 C, find the value of h obtained from the experiment for both A and B.
Comment on whether it is consistent with Einstein’s theory:
Which feature of photoelectric emission could classical wave theory not explain?
What happens to photon energy when frequency increases?
Which is Einstein’s photoelectric equation?
Which expression gives the maximum kinetic energy of emitted photoelectrons?
Why does the maximum kinetic energy of photoelectrons increase when frequency increases?
