Question

What is the velocity of electron present in first Bohr orbit of hydrogen atom?

• A. $2.18\times {10}^{5}m/s$
• B. $2.18\times {10}^{6}m/s$
• C. $2.18\times {10}^{-18}m/s$
• D. $2.18\times {10}^{-9}m/s$

Answer 1

The correct option is B $2.18\times {10}^{6}m/s$

The velocity of electron of the $n^{th}$ stationary state for a hydrogen-like specie is expressed as :

$v_n=2.18\times {10}^6\times \frac{Z}{n}m/s$

where $Z=$atomic number and $n=$ orbit.

For First Bohr orbit of Hydrogen atom, n=1 and Z=1

thus for Hydrogen $v_1\left(H\right)=2.18\times {10}^6\times \frac{1}{1}$ m/s

or the velocity of electron present in first Bohr orbit of hydrogen atom=$v_1\left(H\right)=2.18\times {10}^6$ m/s