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