Question

A current I flows along the length of an infinitely long, straight, and thin-walled pipe. Then ______

Options

• the magnetic field at all points inside the pipe is the same but not zero.

• the magnetic field at any point inside the pipe is zero.

• the magnetic field is zero only on the axis of the pipe.

• the magnetic field is different at different points inside the pipe.

Answer 1

A current I flows along the length of an infinitely long, straight, and thin-walled pipe. Then the magnetic field at any point inside the pipe is zero.

Explanation:

Applying Ampere's law, `ointB.dl = mu_0I,` to any closed path inside the pipe, we find no current is enclosed. Hence, B = 0.