Solid targets of different elements are bombarded by highly en ergetic electron beams. The frequency (f) of the characteristic X-rays emitted from different targets varies with atomic number Z as

Step-by-step solution

According to Moseley's law (Z- ) f or, f (Z- )^2 . Note : The correct answer should have been f (Z- )^2 where is the screening constant. Many authors use at this level, =1 approximately.