A 49m length of wire is stretched horizontally between two v

A 49-m length of wire is stretched horizontally between two vertical posts. The wire carries a current of 62 A and experiences a magnetic force of 0.15 N. Find the magnitude of the earth\'s magnetic field at the location of the wire, assuming the field makes an angle of 65.0° with respect to the wire.

Solution

Using the relation F = Bil sin(theta)

The magnetic field B = F/il sin (theta)

Hence B = 0.15 / (62A)(49m) sin (65) = 5.44x10^-5 T