Manipal MET2016PhysicsMagnetic Effects of Current
A long wire carries a steady current. It is bent into a circle of one turn and the magnetic field at the centre of the coil is B . It is then bent into a circular loop of n turns. The magnetic field at the centre of the coil will be
Options
- An B
- Bn^2 B
- C2 n B
- D2 n^2 B
Correct answer
B. n^2 B
Step-by-step solution
Current, l=2 R=2 n r [ r= R n ] The magnetic field at the centre of the coil, B= ₀ 4 2 I R (i) and B^ = ( ₀ 4 2 I r ) n (ii) From Eqs. (i) and (ii), we get B^ =n^2 B