Chapter 38 - Photons and Matter Waves - Problems - Page 1182: 32a

$\Delta \lambda = 4.85\times 10^{-12}~m$

We can find the Compton shift $\Delta \lambda$: $\Delta \lambda = \frac{h}{mc}(1-cos~\phi)$ $\Delta \lambda = \frac{h}{mc}(1-cos~180^{\circ})$ $\Delta \lambda = \frac{2h}{mc}$ $\Delta \lambda = \frac{(2)(6.63\times 10^{-34}~J~s)}{(9.109\times 10^{-31}~kg)(3.0\times 10^8~m/s)}$ $\Delta \lambda = 4.85\times 10^{-12}~m$