A wire of length l is bent in the form of an equilateral triangle and carries an electric current i. (a) Find the magnetic field B at the centre. (b) If the wire is bent in the form of a square, what would be the value of B at the centre?

Explanation

To solve the problem step by step, we will find the magnetic field at the center of a wire bent in the shape of an equilateral triangle and then for a square.

### Part (a): Magnetic Field at the Center of an Equilateral Triangle

1. **Identify the Geometry**:
- The wire is bent into the shape of an equilateral triangle with a total length \( L \). Each side of the triangle will have a length of \( \frac{L}{3} \).

2. **Determine the Center**:
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