A current i is flowing in a hexagonal coil of side / [Fig.]. The magnetic induction at the centre of the coil will be

See fig. Every angle of equilateral triangle is 60°Distance OG=3l/2 The magnetic induction at O is given byB=6×BAB∴ B=6×μ0i4π(3l/2)sin⁡30∘+sin⁡30∘=6μ0i4π(3l/2)×2sin⁡30∘=3μ0iπl