Question

The distance between $3$rd and $2$nd Bohr orbits of hydrogen atom is:

• A. $0.529\times {10}^{-8}cm$
• B. $2.645\times {10}^{-8}cm$
• C. $2.116\times {10}^{-8}cm$
• D. $1.058\times {10}^{-8}cm$

Answer 1

The correct option is B $2.645\times {10}^{-8}cm$

Radius of Bohr orbit($R_n$) = $R_0\frac{n^2}{z}$

where $R_0=0.529A$

For hydrogen atom,

$R_3=R_0\frac{9}{1}=9R_0=4.761A$

$R_2=R_0\frac{4}{1}=4R_0=2.116A$

$R_3-R_2=5R_0=2.645A=2.645\times {10}^{-8}cm$

The distance between third and second Bohr orbit of hydrogen atom is $2.645\times {10}^{-8}$ cm.