An electron and a photon each have a wavelength of 1.00 nm. Find
(a) their momenta,
(b) the energy of the photon, and
(c) the kinetic energy of electron.

Explanation

Here `lamda=1.00nm=1.00xx10^(-9)m`
(a) Momentum of electron momentum of photon `p=(h)/(lamda)=(6.63xx10^(-34))/(1.00xx10^(-9))=6.63xx10^(-25)kg" "ms^(-1)`.
(b) Energy of photon `E=(hc)/(lamda)p*c=6.63xx10^(-25)xx3xx10^(8)=1.989xx10^(-16)J`
`=(1.989xx10^(-16))/(1.6xx10^(-19))eV=1.24xx10^(3)eV or 1.24keV`.
(c) Kinetic energy of electron `K=(p^(2))/(2m)=((6.63xx10^(-25))^(2))/(2xx9.11xx10^(-31))=2.413xx10^(-19)J`
`=(2.413xx10^(-19))/(1.6xx10^(-19))eV=1.51eV`.