The magnetic induction at the centre O in the figure shown is

In the following figure, magnetic fields at O due to sections 1, 2, 3 and 4 are considered as B1 , B2, B3 and B4, respectively.B1 = B3 = 0B2 = μ04π. πR1 ⊗B4 = μ04π. πiR2 ⊙As   B2   >  B4 So  Bnet  = B2 −B4 ⇒  Bnet  =  μ0i4  1R1 −1R2 ⊗