Question

A long, straight, hollow cylindrical wire with an inner radius $R$ and an outer radius $2R$ carries a uniform current density. Which of the following graphs best represents the magnitude of the magnetic field as a function of distance from axis of wire?

• A. Diagram
• B. Diagram
• C. Diagram
• D. Diagram

Answer 1

The correct option is A Diagram

$J=\frac{I_0}{3\pi R^2}$
For $x<R$ field is zero
For $R<x<2R$
$B.2\pi x=\frac{{\mu }_0{l}_0\pi }{3\pi R^2}(x^2-R^2)$