Q. 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
A) $f \propto \sqrt{Z}$
B) $f \propto Z^{2}$
C) $f \propto Z$
D) $f \propto Z^{3/2}$
Explanation
(b) $\lambda \propto \frac{1}{Z^{2}} \Rightarrow \frac{c}{v} \propto \frac{1}{Z^{2}} \Rightarrow v \propto Z^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.