Two long and parallel straight wires A and B carrying currents of 8.0 A and 5.0 A in the same direction are separated by a distance of 4.0 cm. Estimate the force on a 10 cm section of wire A.
Current in wire A, I1=8 A
Current in wire B, I2=5 A
Force exerted on 10cm section of wire A,
B=μo2I1I2l4πr=2×10−5T
Attractive force normal to A towards B, because current direction same.