An electron revolves in a circle of radius 0.4A⁰ with a speed of 10⁶ m/s in a hydrogen atom. The magnetic field produced at the centre of the orbit due to motion of the electron, in tesla, is $\left[{\mathrm{\mu }}_0=4\mathrm{\pi }\times {10}^{-7}\mathrm{H}/\mathrm{m}\right]$