Cross-section of an infinite cylinder is shown. A current `I` uniformely distributed over its cross-section is flowing along its length. Now a cylinder of radius `R//2` is checked out of this. Then

Options

A. magnetic fields at the centers of both cylinders is same both in magnitude and direction
B. magnetic fields at the centre of both cylideres is same in magnitude but opposite in direction
C. magnetic fields at the centres of both cylinders is same in direction but unequal in magnitude.
D. magnetic field at the centre of both cylinder is opposite in direction and unequal in magnetude

Answer

A

Explanation

In a cylinderical cavity like this, magnetic field uniform, i.e., same both in magnitude and direction