What potential increase vac must an electron be accelerated through if the most energetic photon it can emit will scatter off of a stationary electron at an angle ϕ=60∘ with wavelength 8.4*10-12m? express your answer in kilovolts to two significant digits?

Referring to Compton scattering

Δλ = h/m₀c (I - cos Ф)

λ' = λ = (0,0242*10⁻¹⁰) (1 - cos 60°)

λ = λ' - (0.0242 * 10⁻¹⁰) (1 - cos 60°)

7.19 ˣ 10⁻¹²m

The increased potential is given by

Vₐc = hc/eλ = 6.625 * 10 ⁻³⁴ J, s) (3 * 10⁸ m/s (1.6 ˣ 10 ⁻¹⁰C)

(7.19 ˣ 10⁻¹²m)

173kV.