b
(b) If a wire of length \(l\) is bent in the form of a circle of radius \(r\) then \(2\pi r = l\) \(==>\) \(r = \frac{l}{{2\pi }}\)
\(\vec F = i(\vec L \times \vec B)\)
Magnetic field due to straight wire \({B_1} = \frac{{{\mu _0}}}{{4\pi }} \cdot \frac{{2i}}{r} = \frac{{{\mu _0}}}{{4\pi }} \times \frac{{2 \times 2}}{{1 \times {{10}^{ - 2}}}}\)

also magnetic field due to circular loop \({B_2} = \frac{{{\mu _0}}}{{4\pi }} \cdot \frac{{2\pi i}}{r} = \frac{{{\mu _0}}}{{4\pi }} \cdot \frac{{2\pi \times 2}}{{\pi /2}}\)

\(==>\) \(\frac{{{B_2}}}{{{B_1}}} = \frac{1}{{50}}\)