Two thin, long, parallel wires, separated by a distance 'd' carry a current of 'i' A in the same direction. They will

Options

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

Answer

C

Explanation

Force per unit length,
`(F)/(l)=(mu_(0))(4pi)*(2i_(1)i_(2))/(d)`
`(F)/(l)=(mu_(0))/(4pi)*(2l^(2))/(d)=" " (i= i_(1)=i_(2))`
`(F)/(l)=(mu_(0))/(4pi)*(2 i^(2))/(d)=(mu_(0))/(2pi)*(i^(2))/(d)" "` ( attractive)