Calculate the magnetic field induction at the centre of a hydrogen atom caused by an electron moving along the first Bohrorbit.

Explanation

The revolving is electron is equivalent to a circular current
`I=(e )/(T)=(e )/(2pi r//v)=(ev)/(2pir)`
The magnetic induction
`B=(mu_(0)I)/(2r)=(mu_(0)ev)/(4pir^(2))=(mu_(0))/(4pi).e.(e^(2))/((4pi epsilon_(0)) ħ).[(me^(2))/( ħ^(2)(4pi epsilon_(0)))]^(2)`
`=(mu_(0)m^(2)e^(7))/(256pi^(4)epsilon_(0)^(3) ħ^(5))`
Substitution gives `B= 12.56T` ar the centre.
(In Gaussian units `B=(m^(2)e^(7))/(c ħ^(5))= 125.6kG.`)