Question

The radius of inner most orbit of hydrogen atom is 5.3 x 10^-11 m. What is the radius of third allowed orbit of hydrogen atom?

(1) 1.06 Å

(2) 1.59 Å

(3) 4.77 Å

(4) 0.53 Å

Answer 1

Correct option is (3) 4.77 Å

Radius of n^th orbit in Hydrogen Atom

\(r_n = 0.53 \times \frac{n^2}{Z}Å\)

So, radius of third orbit

\(r_3 = 0.53 \times \frac{(3)^2}{(1)}Å\)

\(= 4.77 Å\)