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Moving Charges And Magnetism

Question
CBSEENPH12037577

A square coil of side 10 cm consists of 20 turns and carries a current of 12 A. The coil is suspended vertically and the normal to the plane of the coil makes an angle of 30° with the direction of a uniform horizontal magnetic field of magnitude 0.80 T. What is the magnitude of torque experienced by the coil?

Solution

Here,
Length of the side of the square,  l = 10 cm = 0.10 m
Number of turns in the coil, N = 20
Current carried by the conductor, I = 12 A 
Angle made by the coil with the magnetic field,θ = 30° 
Magnetic field , B = 0.80 T                    
Area of the conductor A = l × l = 0.1 × 0.1 = 0.01 m2 
Therefore, 

Torque is given by, τ = NBIA sin θ    = 20 × 0.80 × 12 × (0.1)2 × sin 90°    = 0.96 Nm