Question

Solid targets of different elements are bombarded by highly energetic electron beams. The frequency $\left(f\right)$ of the characteristic X-rays emitted from different targets varies with atomic number $Z$ as:

• A. $f\propto \sqrt{Z}$
• B. $f\propto Z^2$
• C. $f\propto Z$
• D. $f\propto Z^{3/2}$

Answer 1

The correct option is B $f\propto Z^2$

Solid targets of different elements are bombarded by highly energetic electron beams. The frequency (f) of the characteristic X-rays emitted from different targets varies with atomic number Z
as $f\propto Z^2$
From Mosley law, $f=a(Z-b{)}^2$. Hence, $f\propto Z^2$.