Q. The radius of the first Bohr orbit of hydrogen atom is 0.529Å. The radius of the third orbit of $H^{+}$ will be

A) 8.46 Å
B) 0.705 Å
C) 1.59 Å
D) 4.79 Å
Explanation

(d)
According to Bohr model,
Radius of hydrogen atom
$\left( r_{n} \right) = \frac{0.529 \times n^{2}}{Z}\mathring{\mathrm{A}}$
(where, $n$=number of orbit, $Z$=atomic number)
$r_{3} = \frac{0.529 \times (3)^{2}}{1} = 4.761\mathring{\mathrm{A}}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.