Question

A photon has momentum of magnitude 8.59x10-28kgm/s. What is the energy of this photon in eV?

Answer 1

`"1.61 eV"`

Explanation:

For a photon wavelength is given as `λ = h/p` where `p` is momentum.

`λ = h/p = (6.626 × 10^-34 "J s") / (8.59 × 10^-28 "kg m/s") = 7.71 × 10^-7 "m"`

Energy is given as `E = (hc)/λ`

`E = (hc)/λ = (6.626 × 10^-34 "J s" xx 3 × 10^8 "m/s")/(7.71 × 10^-7 "m") = 2.58 × 10^-19 "Joule"`

Now, convert energy in joules to energy in eV

`2.58 × 10^-19 cancel"Joule" × "1 eV"/(1.602 × 10^-19 cancel"Joule") = "1.61 eV"`