Question

At what potential difference must an X-ray tube operate to produce X-rays with a
minimum wavelength of 2A. °

Answer 1

From the conservation of energy:

$$eU=\frac{hc}{λ}$$

$$U=\frac{hc}{eλ}=\frac{1239.84 eVnm}{(1e)(0.2 nm)}=6200 V=6.2 kV$$