1. The problem statement, all variables and given/known data Two very long, thin, straight, parallel wires each carrying a current I in the same direction are separated by a distance, d. With the aid of a diagram which indicates the current directions, account for the force on each wire and show on the diagram the direction of one of the forces. Write an expression for the magnitude of the force per unit length of wire and hence define the ampere. 2. Relevant equations 3. The attempt at a solution did necessary steps to get to force/length=uoI2/2pi*d then at 1m separation F=2*10-7I2 From text: "if two long parallel wires 1m apart carry equal currents and experience a force of of 2*10-7N then the current is defined to be 1Ampere" I think im pretty close to the answer but I have a force of 2*10-7I2 -how do I get rid of the I2????