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
Ω. Two resistances of 6Ω and 3Ω are connected as shown in figure. The external force required to keep the connector moving with a constant velocity v = 2m/s is
Motional emf e=Bvl⇒ e=2× 2× 1=4 V
This acts as a cell of emf E=4V and internal resistance r=2Ω.
This simple circuit can be drwan as follows
Current through the connector i=42+2=1 A
∴ Magnetic force on connector Fm==Bil=2× 1× 1=2 N (Towards left)