Question

Why does the needle of a magnetic compass deflect when it is kept beside a current carrying wire?

Answer 1

Hint: Moving electric charges produce an electric field, whereas stationary charges produce a magnetic field. Electric fields are created by stationary charges. When a non-relativistic proton beam passes across a region of space without deviating, we may state that the force due to the magnetic field equals the force owing to the electric field. The relationship between the magnetic and electric fields may then be determined.

Complete step by step solution:
A magnetic compass is composed of magnetised iron that points to the earth's pole. When another magnet is brought close enough, the compass will point in the direction of the second magnet since its magnetic strength is greater than that of the earth. When a current carrying wire is introduced close to a magnetic compass, the magnetic compass will deflect owing to the development of a magnetic field. A wire carrying electric current will have a magnetic field that forms concentric rings around it. One of the magnet's ends will attract, while the other will repel, depending on its orientation.
Because the electric field is exactly proportional to the magnetic field intensity, the deflection will rise as the current is increased. We may say that the magnetic field is stronger when the electric field is strong. A current carrying wire generates a magnetic field around it, which causes the needle of a magnetic compass to deviate.

Note:
When an electric current runs through a wire, the wire takes on the properties of a magnet. A magnetic compass is composed of magnetised iron that points to the earth's pole. When a non-relativistic proton beam passes across a region of space without deviating, we may state that the force due to the magnetic field equals the force owing to the electric field.