A circular loop carrying a current i has wire of total length L. A uniform magnetic field B exists parallel to the plane of the loop.

(a) Find the torque on the loop.


(b) If the same length of the wire is used to form a square loop, what would be the torque? Which is larger?


Given-
Magnetic field intensity = B


Magnitude of current = i


Circumference, ,


where


r is the radius of the coil



So, area of the coil,



Torque acting on the coil,




Where


B= applied magnetic field


A= area of rectangular loop


I = current flowing through coil


= angle between the area vector and magnetic field




(b) Let s be the length of the square loop.


Then given in the question that







So, the torque in case of the circular loop is larger.


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