A rectangular coil of size 3.0 cm X 4.0 cm and having 100 turns, is pivoted about the z-axis as shown in figure the colil carries an electric current of 2.0 A and a magnetic field of 1.0 T is present along the y-axis. Find the torque acting on the coil if the side in the x-y plane makes an angle `theta= 37^@` with the x - axis.

Explanation

The magnetic moment of the loop is `vecmu = nivecA where n is the number of truns, I is the current and vec A is the area vecto . The direction of vecA is determined by the sense of the current and in this case it lies in the fourth quadrant making an angle theta=37^@ with the megativ y-axis. Torque `vec GAMMA = vecmuX vecB= ni vecAX vecB. Thus, GAMMA = vec 100X(2A)X(12X10^(-4)m^2)X 1 TX sin37@. = 0.14Nm. The torque is along the positive z-axis.