Q- A horizontal wire of length 0.10m and mass 0.020kg carries a current in the earth’s magnetic field where it is horizontal and of magnitude 5.0*10^-5 T.                            

a) Determine the minimum magnitude of the current in the wire if the wire remains motionless in the air above the surface of the earth in the magnetic field.                    

b) Show, by means of a drawing, the relative direction of the current and the magnetic field.

Solution: