Write a short note on Threshold Frequency (v0) and Threshold wavelength (&lemda;).
Physics
Class 12
859
Valentina
Threshold Frequency (v0) :
Minimum frequency of incident photon below which no ejection of photoelectrons from a metal surface can take place is known as threshold frequency for that metal. Its value is constant for a particular metal but may be different for different metals.
If v = Frequency of incident phtoton & v0 = Threshold Frequency then
Threshold wavelength (0) :
Maximum wavelength of incident photon above which there will be no photoelectric emission from a metal surface is known as threshold wavelength
L0 = 0 c
If L = wavelength of incident photon then
(a) if λ < 0 then photo electric effect will take place and ejected electron will possess kinetic energy.
(b) if = 0 then Photo electric effect will just take place and kinetic energy of ejected photo electron will be zero (c) if > 0 there will be no Photo electric effect.