A current carrying coil is bent sharply so as to convert it into a double loop both carrying current in the same direction. If B be the initial magnetic field at the centre, then what will be the final concentric magnetic field?

Step-by-step solution

Radius of the double loop, r= R 2 where, R is the radius of single loop B (centre) = ₀ 4 2 I R . So, magnetic field due to each coil is double of that due to single coil. and total magnetic field =2 B+2 B=4 B