Two straight wires A and B of lengths 10 m cach carrying currents of 4.0 A and 6.0 A in opposite directions lic parallel to each other at a distance of 2 cm. Estimate the force on a 10 cm section of the wire B near its centre.

Explain why two parallel wires carrying currents in opposite directions repel each other.

Two straight parallel wires A and B, cach 20 cm long are separated by 10 cm. They carry 20 A and 30 A current respectively in opposite directions. Calculate the magnetic field (i) the mid point

Two straight parallel wires A and B, cach 20 cm long are separated by 10 cm. They carry 20 A and 30 A current respectively in opposite directions. Calculate the magnetic field at (ii) the point 5 cm from A and 15 cm from B on the line joining them.

Two long straight thin conductors carrying currents I_1 and I_2 respectively along the same direction are placed parallel to each other in air. Derive an expression for the force per unit length acting on any one of the conductors and hence define one ampere current.

Find the force between two straight parallel wires, each of length one metre and cach carrying a current of 100 amperes when separated by a distance of one metre (given mu_0 = 4pi x 10^-7 N/m) .