Question

Q. How can it be shown that magnetic field exists around a wire carrying current?

Answer 1

If we were to bring near a wire a compass needle then it would show deflection which basically proves that there is an existant magnetic field since the wire is carrying current.

The deflection that is basically shown occurs due to the force of attraction or the repulsion that is caused in the magnetic field due to the direct current and the presence of the magnet in the compass.

Answer 2

"To show the presence of a magnetic field around a wire carrying current, we need to follow the following steps;

1. Take a wire and bring it near to a compass needle.
2. As we bring it close to the compass, the needle will show some    deflection.
3. The deflection in the needle proves that there must be some "magnetic field" exists in a wire when it carries electric current.

The deflection of the needle is because of the force of "attraction or repulsion" due to a magnetic field which is because of the flow of direct current."