Mark out the correct statement regarding X-rays.

Options

A. When fast moving electrons strike the metal target, they enter the metal target and in a very short time, they come to rest, and thus an accelerated charged electron produces electromagnetic waves (X-rays).
B. Characteristic X-rays are produced due to transition of an electron from higher energy levels to vacant lower energy levels.
C. X-rays spectrum is a discrete spectra just like hydrogen spectra.
D. Both (a) and (b) are correct.

Answer

B

Explanation

Option (a) explains the production of X-rays on the basis of electomagnetic theory of light, which is not able to explain the characteristic X-rays and cut-off wavelength, so option (a) is wrong.
Option (b) correctly explains the production of characteristic X-rays.
Option (c) is wrong as X-ray spectra is a continusous spectra having some peaks representing characteristic X-rays.