An electrical wire is strung horizontally between two utility poles. The current is travelling toward the east. a) State the rule used to determine the direction of the force on the wire due to Earth's magnetic field. (1C) b) Give the formula for calculating the magnitude of the magnetic force on the wire due to Earth's magnetic field. (1C) c) Predict what would happen to the magnetic field if the current were to flow toward the west. Justify your prediction. (2C)