Modern Physics 2 Question 12
12. Radiation of wavelength , is incident on a photocell. The fastest emitted electron has speed . If the wavelength is changed to , the speed of the fastest emitted electron will be
(2016 Main)
(a)
(b)
(c)
(d)
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Solution:
- According to the law of conservation of energy, i.e. Energy of a photon
Work function Kinetic energy of the photoelectron
According to Einstein’s photoelectric emission of light i.e.
As,
If the wavelength of radiation is changed to