Question

A thick copper conductor is held parallel to a freely pivoted magnetic needle, as shown in the diagram alongside. Answer the question given below:

If the magnitude of current in the conductor is gradually increased the maximum angle through which magnetic needle will turn is :

Options

• 90°

• 45°

• 60°

• none of these

Answer 1

90°

Explanation:

As the current increases, the deflection of the magnetic needle increases until the north pole points at right angles to the wire, so the maximum deflection is 90°. Angles of 45° and 60° are not the maximum deflection.