Teaching NVS PGT 2024 Test Series Physics Moving Charges and Magnetism Magnetic Field on the Axis of a Circular Current Loop
A long straight wire of radius a carries a steady current I. The current is uniformly distributed across its cross section. The ratio of the magnetic field at \(\frac{a}{2}\) and 2a from axis of the wire is :
1
1 : 4
2
4 : 1
3
1 : 1
4
3 : 4