A long straight wire of radius 10mm carries a current uniformly distributed over its cross section. The ration of magnetic fields due to the wire at distance of 5mm and 15 mm, respectively from the axis of the wire is

A long, straight wire of radius R carries a current distributed uniformly over its cross section. The magnitude of the magnetic field is

A long, straight wire of radius R carries a current distributed uniformly over its cross section. The magnitude of the magnetic field is

A long, straight wire of radius R carries a current distributed uniformly over its cross section. The magnitude of the magnetic field is

A long straight wire of radius a carries a steady current I. The current is uniformly distributed over its cross section. The ratio of the magntic fields B and B' at radii distance (a)/(2) and 2a respectively, from the axis of the wire is

A long straight wire of radius carries a steady current I. The current is uniformly distributed over its cross - section. The ratio of the magnetic fields B and B', at a radial distances a/2 and 2a respectively, from the axis of the wire is