37.
(a) Since the mass of an electron is m = 9.109
× 10
−31
kg, its Compton wavelength is
λ
C
=
h
mc
=
6.626
× 10
−34
J
·s
(9.109
× 10
−31
kg)(2.998
× 10
8
m/s)
= 2.426
× 10
−12
m = 2.43 pm .
(b) Since the mass of a proton is m = 1.673
× 10
−27
kg, its Compton wavelength is
λ
C
=
6.626
× 10
−34
J
·s
(1.673
× 10
−27
kg)(2.998
× 10
8
m/s)
= 1.321
× 10
−15
m = 1.32fm .
(c) We use the formula developed in Exercise 3: E = (1240 eV
·nm)/λ, where E is the energy and λ
is the wavelength. Thus for the electron, E = (1240 eV
·nm)/(2.426 × 10
−3
nm) = 5.11
× 10
5
eV =
0.511 MeV.
(d) For the proton, E = (1240 eV
·nm)/(1.321 × 10
−6
nm) = 9.39
× 10
8
eV = 939 MeV.