Two long and parallel straight wires A and B carrying currents of 8.0 A and 5.0 A in the same direction are seperated by a distance of 4.0 cm . Estimate the force on a 10 cm section of wire A.

Explanation

`I_1 = 8.0 A, I_2 = 5.0 A, r = 4.0 cm = 4.0 xx 10^(-2) m `
I = 10 cm = 0.1 m
`F= (2 xx 10^(-7) I_1I_2)/(r) = (2 xx 10^(-7) xx 8 xx 5 xx 0.1)/(4 xx 10^(-2))= 2 xx 10^(-3)N` ( towards B)