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 = 20 xx 10^(3) e V`
The energy of the photon is
`0.05 xx 20 xx 10^(3) e V = 10^(3) e V`
Thus `(hc)/(lambda) = 10^(3) e V`
implies `lambda = ((4.14 xx 10^(-15) e V - s) xx (3 xx 10^(8) m s^(-1)))/(10^(3) e V)`
=` (1242 e V - n m )/(10^(3) e V = 1.24 n m`