Question

If a current $I$ is flowing in a loop of radius $r$ as shown in adjoining figure, then the magnetic field induction at the centre $O$ will be

• A. Zero
• B. $\frac{\mu_{0}I \theta}{4\pi r}$
• C. $\frac{\mu_{0}I sin \theta}{4\pi r}$
• D. $\frac{2\mu_{0}I sin \theta}{4\pi r^{2}}$

Answer 1

Answer: (B)

$\frac{\mu_{0}I \theta}{4\pi r}$

Answer 2

Magnetic field B = $\frac{\mu_{0}}{4\pi}\frac{2\pi I}{r}$
Here, $2\pi=\theta$
$\therefore B=\frac{\mu_{0}}{4\pi}\frac{\theta I}{r}$