A long flexible wire is bent either into a square coil or into a circular coil

PHYSICS · Single correct · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism

Problem

A long flexible wire is bent either into a square coil or into a circular coil, each having the same total length of wire and the same number of turns. Both coils carry the same current

I

and are kept in the same uniform magnetic field

B

with their planes parallel to each other and positioned for maximum torque. What is the ratio of the maximum torque on the circular coil to that on the square coil? (a)

\dfrac{\pi}{4}

(b)

\dfrac{4}{\pi}

(c)

1

(d)

\pi

Related theory

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Torque on current loop
Torque on a current loop
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