A helium nucleus makes full rotation in a circle of radius 0.8 metre in two seconds. The value of the magnetic field B at the centre of the circle will be
(a) \(\cfrac{10^{-19}}{\mu_0}\)
(b) 10-19 μ0
(c) 2 x 10-10 μ0
(d) \(\cfrac{2\times 10^{-10}}{\mu_0}\)
