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Question
Briefly explain the three observed features which can be explained by Einstein’s photoelectric equation.
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Solution
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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RELATED QUESTIONS
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.
Is p − E/c valid for electrons?
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(B) The maximum kinetic energy of the photoelectrons is doubled.
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Comment on whether it is consistent with Einstein’s theory:
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Surface A: no photoemission occurs
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Surface C: photo emission occurs and photoelectrons have some kinetic energy.
Using Einstein’s photo-electric equation, explain the three observations.
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