The wires which connect the battery of an automobile to its starting motor carry a current of 300 A (for a short time). What is the force per unit length between the wires if they are 70 cm long and 1.5 cm apart? Is the force attractive or repulsive?
The force between two wires is given by the relation, F=2πrμoI2=1.2 N/m Since the direction of current in two wires is opposite, a repulsive force exists between them.
