Three coplanar parallel wires, each carrying a current of 10 A along the same direction, are placed with a separation 5.0 cm between the consecutive ones. Find the magnitude of the magnetic force per unit length acting on the wires.

Explanation

For wire W_1
`(dF)/(dl) = (mu_oxx10xx10)/(2pixx5xx10^(-2) + (mu_o xx10xx10)/(2pixx5xx10^(-2)`
`=(2xx10^(-7)xx10^2)/(5xx10^(-2) + (2xx10^(-7)xx10^2 )/(10xx10^(-2)`
`=4xx10^(-4)+2xx10^(-4)`
`=6xx10(-4) N towards right`
For wire `W_2,`
`(dF)/(dl) = (mu_oxx10xx10)/(2pixx5xx10^(-2)) - (mu_oxx10xx10)/(2pixx5xx10^(-2)) = 0`
For wire `W_3`
(dF)/(dl)= (mu_oxx10xx10)/(2pixx 5 xx10^(-2)+ (mu_oxx10xx10)/(2pixx5xx10^(-2)`
towards left
`=6xx10^(-4)N towards left.`