Question

The ratio of the speed of the electrons in the ground state of hydrogen to the speed of light in vacuum is
A. `(1)/(2)`
B. `(2)/(237)`
C. `(1)/(137)`
D. `(1)/(237)`

Answer 1

Correct Answer - C
Speed of the electron in the ground state of hydrogen atom is `v=(2pie^2)/(4piepsilon_0h)=(c)/(137)=calpha`
where , `c=`speed of light in vacuum, `alpha =(e^2)/(2epsilon_0hc)` is the fine structure constant. It is pure number whose value is `(1)/(137)`.
`therefore (v)/(c)=(1)/(137)`