A wire of length L is bent into an arc of a circle and found to subtend an angle of θ radians at the center. If a current i is passed through it, the magnetic induction at the center of the circle is?

 μ_oiθ²/4πL

Magnetic field at the center of the circular coil carrying current : \(\frac{\mu_{o}}{4\pi}\) \(\frac{i}{r}\) \(\theta\)

Use: L = r \(\theta\)

r = \(\frac{L}{\theta}\)