A long straight wire carries a current `I_(0)`, at distance `a` and `b=3a` from it there are two other wires, parallel to the former one, which are interconnected by a resistance `R`(figure).A connector slides without friction along the wires with a constant velocity `v`.Assuming the resistance of the wires,the connector, the sliding contacts and the self-inductance of the frame to be negligible. The point of application (distance from the long wire) of magnetic force on sliding wire due to the long wire is `(2a)/(lnx)` from long wire.Then find out value of `x`.

Answer

C

Explanation

`int`(Torque of elecentary force)=Torque of net force.
`(mu_(0)I_(0))/(2pi)Iint(xdx)/x=F_(0)barx=(mu_(0)I_(0))/(2pi)I ln (b/a) barx rArr barx=(b-a)/(ln(b//a))rArrbarx=(2a)/(ln3) rArr x=3`