An X-ray tube operates at 20 kV. A particular electron loses 5% of its kinetic energy to emit an X-ray photon at the first collision. Find the wavelength corresponding to this photon.

Explanation

Kinetic energy acquired by the electron `=20xx10^(3)eV`
The energy of the photon
`=(5)/(100)xx20 xx10^(3)eV = 10^(3)eV`
Thus `(hc)/(lambda)=10^(3)eV`
or `lambda=(hc)/(10^(3)eV)=(12400eV-Å)/(10^(3)eV)=12.4Å`