Q. A long cylindrical conductor with large cross section carries an electric current distributed uniformly over its cross-section. Magnetic field due to this current is:

Choose the correct answer from the options given below:

Correct Answer: D Only

Solution

For a long cylindrical conductor carrying current uniformly distributed over its cross-section, the magnetic field inside the conductor varies with distance from the axis.

Using Ampere’s law, the magnetic field inside the conductor at a distance r from the axis is directly proportional to r:

B ∝ r

This means the magnetic field is zero at the axis of the conductor and increases linearly as we move away from the axis.

Hence, the magnetic field is minimum at the axis of the conductor and maximum at the surface.

Therefore, the correct statement is D only.

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