378 7 Nuclear Physics – I
Maximum shift in wavelength(Δλ)max= 2 λc (7.38b)Shift in frequency
ν=ν 0 /(1+α(1−cosθ)) (7.39a)
whereα=hν 0 /mc^2 (7.39b)
Δν=ν 0 −ν=αν 0 (1−cosθ)/(1+α(1−cosθ))Energy of recoil electron
T=hν 0 −hν=αhν 0 (1−cosθ)/(1+α(1−cosθ)) (7.40)Angular relation
cotφ=(1+α)tan(θ/2) (7.41)Compton attenuation coefficients
I=I 0 exp(−μcx) (7.42)Ifxis in cm thenμcis in cm−^1 ;ifxis in g/cm^2 which is obtained by multiplying
xcm byρ(the density), thenμis in cm^2 /g
Photoelectric effect
If the incident photon is absorbed by an electron in the atom or metal, and the
electron is ejected then the process is known as photoelectric effect. The kinetic
energy of the photoelectron
T=hν−W ( Einstein’s equation) (7.43)whereWis the ionization energy of the ejected electron
eVo=1
2
mν^2 max=hν−W (7.43a)Threshold energyhν 0 =W (7.44)