Question

1. 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
a/4 inside and a/4
outside from the surface of wire
is
(1) 1 : 1
(2) 7:16
(3) 15:16
(4) 16:9
​

Answer 1

1:1

throught amoere curcuital loop

outside the wire magnetuc field is indirectly propotional to a/4 and inside it is directly propotinal to a/4