Magnetic Moment

Step 1: Understanding the concept of magnetic moment.
The magnetic moment of a current-carrying wire is given by the product of the current and the area enclosed by the wire.
Step 2: Relation for bend-shaped wire.
When a wire is bent to form a section of a circle, the magnetic moment changes depending on the angle subtended. For a section of a circle subtending an angle , the magnetic moment of the bend-shaped wire will be proportional to the original magnetic moment, modified by the fraction of the full circle subtended. The formula for the magnetic moment of the bend-shaped wire is:
Given that , the magnetic moment becomes:
Therefore, the magnetic moment of the bend-shaped wire is . Thus, the correct answer is
(B) .