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AP EAMCET · PHYSICS · Magnetic Effects of Current

A square frame of side \(1 \mathrm{~m}\) carrying a current \(I\) produces a magnetic field \(B\) at its centre. The same current is passed through a circular coil having the same perimeter as the square. The magnetic field at the centre of the circular coil is \(B^{\prime}\). The ratio of \(\frac{B}{B^{\prime}}\) is

  1. A \(\frac{8}{\pi^2}\)
  2. B \(\frac{8 \sqrt{2}}{\pi^2}\)
  3. C \(\frac{16}{\pi^2}\)
  4. D \(\frac{16}{\sqrt{3} \pi^2}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{8 \sqrt{2}}{\pi^2}\)

Step-by-step Solution

Detailed explanation

Given, Side of square frame, \(a=1 \mathrm{~m}\) Electric current \(=I\) For square, Let \(r\) be the distance of centre \(O\) from all sides, \(r=\frac{a}{2}\) Since, all sides of square produces equal field in the same direction. Using,…