A rectangular coil of 100 turns has length 5 cm and width 4 cm. It is placed with its plane parallel to a uniform magnetic field and a current of 2A is sent through the coil. Find the magnitude of the magnetic field B, if the torque acting on the coil is 0.2 N m–1.


Given-
No. of turns in the coil, n = 100



Area of the coil, A = 5 × 4 cm2 = 20 × 10−4 m2



Magnitude of current = 2 A



Torque acting on the coil, τ = 0.2 N m−1


We know that torque acting on a rectangular coil having n turns is given by



Where


B= applied magnetic field


A= area of rectangular loop


I = current flowing through coil


n = number of turns










1