Q. Radius of the first orbit of the electron in a hydrogen atom is $0.53\ \mathring{\mathrm{A}}$. So, the radius of the third orbit will be
A) $2.12\ \mathring{\mathrm{A}}$
B) $4.77\ \mathring{\mathrm{A}}$
C) $1.06\ \mathring{\mathrm{A}}$
D) $1.59\ \mathring{\mathrm{A}}$
Explanation
(b) $r_{n} \propto n^{2} \Rightarrow \frac{r_{3}}{r_{1}} = \frac{3^{2}}{1} \Rightarrow r_{3} = 9r_{1} = 9 \times 0.53 = 4.77\mathring{\mathrm{A}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.