Question

A long straight wire of radius 'a' carries a steady current 'I'. The current is uniformly distributed across its area of cross-section. The ratio of magnitude of magnetic field B₁ at a/2 and B₂ at distance 2a is

The current I flowing through a conductor of radius r is uniformly distributed across its cross-section. Which of the following graphs represents the variation of magnitude of magnetic field B with distance x from the axis of the conductor ?