Question

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

Options

• 1.06 Å

• 1.59 Å

• 4.77 Å

• 0.53 Å

Answer 1

4.77 Å

Explanation:

(c) In bohr's model, the radius of n^th orbit is

\[r_{n^{\mathrm{th}}}=r_0\frac{A^2}{Z}\]

(Symbols have their usual meanings)

For H-atom, and for n = 3

r_n^th = r₀ (3)²   

= 0.53 × 9

= 4.77Å