Consider three long straight parallel wires as shown in figure. Find the force experienced by a 25 cm length of wire C (μN)

Repulsion by wire D, F1=μ02πi1i2lr   towards right]=2×10−7(30×10)3×10−2(0.25)=5×10−4NRepulsion by wire G,F2=2×10−7(20×10)5×10−2(0.25)=2×10−4N∴ Fnet =F1−F2=300×10−6N