Question

The magnetic field induction at the centre of a coil bent in the form of a square of side 2a carrying current I is

Answer 1

Answer:

A coil in the form of a square of a side 2a carries a current l

consider wire AB.

Distance form C = a (Ref - image )

Now, magnetic field due to a finite wire carrying current l at a point is given by at a distance.

B= Hol/2r ( sin × + sin B)

(Ref image 2)

so magnetic field at B due to AB:

B1. Hol/ 4ra (sin 45+sin 45)

B1.hol/4ra (2)

(from geometry × = 2

B=45)

Similarly other wire contributes to same field in same direction given as .

B= 4B ,=4×Hol/4ra(2)

B=2 Hol/ra