All Problems

Thermal Radiation. Quantum Nature of Light.

Problem 5.288

A photon is scattered at an angle \(\theta=120^{\circ}\) by a stationary free electron. As a result, the electron acquires a kinetic energy \(T=0.45 \mathrm{MeV}\). Find the energy that the photon had prior to scattering.

Reveal Answer
ω=[1+1+2mc2/Tsin2(θ/2)]T/2=0.68MeV\hbar \omega=\left[1+\sqrt{1+2 m c^{2} / T \sin ^{2}(\theta / 2)}\right] T / 2=0.68 \mathrm{MeV}