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When ultraviolet rays incident on metal plate then photoelectric effect does not occur, it occurs by incidence of : -
A
Infrared rays
B
X-rays
C
Radio wave
D
Light wave
Detailed Solution
Photoelectric emission occurs only if the frequency of the incident radiation is greater than the threshold frequency of the metal ($h\nu \gt \phi$).
Ultraviolet rays do not cause emission, so the threshold frequency of this metal is higher than the frequency of ultraviolet light.
Hence only radiation of still higher frequency (shorter wavelength) can cause emission.
Infrared, radio waves and visible light all have lower frequencies than ultraviolet, so they cannot. X-rays have a higher frequency than ultraviolet.
So photoelectric effect occurs by incidence of X-rays.
Ultraviolet rays do not cause emission, so the threshold frequency of this metal is higher than the frequency of ultraviolet light.
Hence only radiation of still higher frequency (shorter wavelength) can cause emission.
Infrared, radio waves and visible light all have lower frequencies than ultraviolet, so they cannot. X-rays have a higher frequency than ultraviolet.
So photoelectric effect occurs by incidence of X-rays.