Question

One of the two identical conducting wires of length $L$ is bent in the form of a circular loop and the other one into a circular coil of $N$ identical turns. If the same current is passed in both, the ratio of the magnetic field at the central of the loop $(B_L)$ to that at the centre of the coil $(B_C)$ , i.e., $R \frac{B_L}{B_C}$ will be

• A. $\frac{1}{N}$
• B. $N^2$
• C. $\frac{1}{N^2}$
• D. $N$

Answer 1

Answer: (C)

$\frac{1}{N^2}$

Answer 2

$L = 2 \pi R$ $L = N \times2\pi r$
$R =Nr$
$B_{L} = \frac{\mu_{0} i}{2R}$