While sitting in front of a color TV with a $25 \mathrm{kV}$ picture tube potential, you have an excellent chance of being irradiated with $\mathrm{X}$-rays.

For the resulting continuous distribution, calculate the shortest wavelength (maximum energy) X-ray.
When a high voltage is applied to the picture tube, electrons emitted from the negative electrode will be accelerated by the electric field to strike the screen target. If the energy of the electrons exceeds a certain value, they can knock off inner-shell electrons in the target atoms and make holes in the inner shells. Then as the outer-shell electrons fall in to fill up these holes, X-rays are emitted.
The maximum energy of the X-ray photons produced, $h \nu_{\max }$, is equal to the energy $\mathrm{eV}$ of the incident electrons. Hence the minimum wavelength of the X-rays is

$$
\lambda_{\min }=\frac{h c}{e V}=\frac{12000}{V}=\frac{12000}{25 \times 10^{3}}=0.48 \AA .
$$