Answer
$\lambda = 6.2\times 10^{-12}~m$
Work Step by Step
We can find the wavelength of a photon produced by a 0.20-MV x-ray machine:
$E = \frac{hc}{\lambda}$
$q~\Delta V = \frac{hc}{\lambda}$
$\lambda = \frac{hc}{q~\Delta V}$
$\lambda = \frac{(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{(1.6\times 10^{-19}~C)(0.20\times 10^6~V)}$
$\lambda = 6.2\times 10^{-12}~m$
