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 is
`K = eV = 20 xx (10^3)eV.
The energy of the photon
`= 0.05 xx 20 xx (10^3) eV = (10 ^3) eV.
Thus, `(hc)/(lambda) = (10 ^ 3) eV`
or, `lambda = (hc)/(10 ^3 eV)`
`=((4.14 xx 10 ^(-15)eVs) xx(3 xx 10 ^(8)ms^(-1)))/(10^3eV)`
= `(1242 eV nm)/(10^3 eV) = 1*24 nm`.