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Question:

One of the two identical conducting wires of length $\mathrm{L}$ is bent in the form of a circular loop and the other one into a circular coil of $\mathrm{N}$ identical turns. If the same current is passed in both, the ratio of the magnetic field at the central of the loop $\left(B_{1}\right)$ to that at the centre of the coil

$\left(\mathrm{B}_{\mathrm{C}}\right)$, i.e., $\frac{\mathrm{B}_{\mathrm{L}}}{\mathrm{B}_{\mathrm{C}}}$ will be:

1. $\mathrm{N}$

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

3. $\mathrm{N}^{2}$

4. $\frac{1}{\mathrm{~N}^{2}}$

Correct Option: 4

JEE Main Previous Year 1 Question of JEE Main from Physics Moving Charges and Magnetism chapter.
JEE Main Previous Year 9 Jan 2019, II

Solution:

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