Two long parallel straight wires X and Y separated by a distance `5cm` in air carry currents of `10A` and `5A` respectively in opposite directions. Calculate the magnitude and direction of force on a `20cm` length of the wire Y. Figure

Answer

`4xx10^-5N`; Repulsion

Explanation

`F=(mu_0)/(4pi)(2I_1I_2l)/(r)=10^-7xx(2xx10xx5xx0*20)/(0*05)`
`=4xx10^-5N`
The distance of `vecF` is perpendicular to the length Y and acts away from X (i.e. repulsion).