A rectangular loop with a sliding connector of length `l = 1.0 m` is situated in a uniform magnetic field `B = 2T` perpendicular to the plane of loop. Resistance of connector is `r = 2 Omega`. Two resistances of `6Omega` and `3Omega` are connected as shown in . The external force required to keep the connetor moving with a constant velocity `v = 2 m s^(-1)` is