Question

A cylindrical conductor of radius R is carrying a
constant current. The plot of the magnitude of
the magnetic field, B with the distance, d, from
the centre of the conductor, is correctly
represented by the figure :
​

Answer 1

Let i is the current through cylinderical conductor.

case 1: inside the conductor, (d < R)

magnetic field , B = $\frac{\mu_0id}{2\pi R^2}$

here it is clear that B is directly proportional to d. so, graph will be straight line which initiates from origin.

case 2 : surface of conductor (d = R)

magnetic field, B = $\frac{\mu_0i}{2\pi R}$

magnetic field at the surface of conductor is constant.

case 3 : outside the conductor (d > R)

magnetic field , B = $\frac{\mu_0i}{2\pi d^2}$

magnetic field outside the conductor is inversely proportional to d²

so, graph will be decreasing parabolic.

you can see final graph as shown in figure.

Answer 2

Answer:

3.

Explanation: