Two mutually perpendicular concentric current carrying coils have the same radius 2π cm.  If currents 3 A and 4 A flow in each coil respectively, then calculate the magnitude of magnetic induction (in Wb/m2) at the common centre of the two coils.μ0=4π×10−7WbAm−1

The magnetic field at the centre of a circular of a circular loop is given by ;B=μ0i2rThus,B1=μ0i12r=μoi122π×10−2=μo×3×1024π B2=μ0i22r=μoi222π×10−2 =μo×4×1024πSince B1 and B2 are perpendicular to each other, resultant magnetic field is :Bnet=B12+B22=μo4π5×102Bnet =10−7×5×102Bnet=5×10−5Wb/m2