Question

A 45-m length of wire is stretched horizontally between twovertical posts. The wire carries a current of 76 A and experiences a magnetic force of 0.15 N. Findthe magnitude of the earth's magnetic field at the location of thewire, assuming the field makes an angle of 55.5° with respect to the wire.

Answer 1

Length L = 45 m

Current I = 76 A

Angle θ = 55.5 degrees

Force F = 0.15 N

We know F = BiL sin θ

From this magnetic field B = F / ( iL sin θ)

                                        = 5.32*10^-5 T