Two thin long parallel wires separated by a distance 'b' are carrying a current ' I' amp each . The magnitude of the force3 per unit length exerted by one wire on the other is

Options

A. `(mu_0i^2)/(b^2)`
B. `(mu_0i^2)/(2pib)`
C. `(mu_0i)/(2pib)`
D. `(mu_0i)/(2pib^2)`

Answer

B

Explanation

Force per unit length between two wires carrying currents `i_1`
and `i_2` at distance r is given by
`F/l=(mu_0)/(2pi) (i_1i_2)/r`
Here, `i_1=i_2=i and r=b`
`F/l=(mu_0i^2)/(2pib)`