Answer
See explanation.
Work Step by Step
The accelerating voltage gives kinetic energy to the electrons, which then produce the x ray photons.
a. $$eV=\frac{hc}{\lambda}$$
$$V =\frac{hc}{ e \lambda}=
\frac{(6.626\times10^{-34}J \cdot s)(3.00\times10^8 m/s)}{(1.602\times10^{-19}C) (0.150\times 10^{-9}m )}=8.27\times 10^{3}volts$$
b. $$eV=\frac{hc}{\lambda}$$
$$\lambda =\frac{hc}{ eV}=
\frac{(4.136\times10^{-15}eV \cdot s)(3.00\times10^8 m/s)}{(30000eV)}=4.14\times 10^{-11}m$$
