Two thin long parallel wires separated by a distance `b` are carrying a current `i` amp each . The magnitude of the force per unit length exerted by one wire on the other is

Options

A. `(mu_(0)i^(2))/(b^(2))`
B. `(mu_(0)i^(2))/(2pib)`
C. `(mu_(0)i)/(2pib)`
D. `(mu_(0)i)/(2pib^(2))`

Answer

B

Explanation

Force per unit length`=(mu_(0))/(4pi).(2i_(1)i_(2))/(r)=(mu_(0))/(2pi).(i^(2))/(b)`