An electron moving in a circular orbit of radius r makes n rotations per second. The magnetic field produced at the centre has magnitude
μ0n2er
μ0ne2r
μ0ne2πr
Zero
Current in the orbit, I=eT
I=e(2π/ω)=ωe2π=(2πn)e2π=ne
Magnetic field at centre of current carrying circular coil is given by
B=μ0I2r=μ0ne2r