Q6.14 (d) Figure 6.20 shows a metal rod resting on the smooth rails and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer connects the rails through a switch . Length of the , , resistance of the closed loop containing the . Assume the field to be uniform. Suppose K is open and the rod is moved with a speed of in the direction shown. Give the polarity and magnitude of the induced emf.What is the retarding force on the rod when K is closed?
The formula to calculate the force on the conductor moving in a magnetic field is,
Where,
is the induced current.
is the magnetic field strength.
is the length of the conductor.
The induced current is calculated as,
The length of the rod is 0.15 m.
Magnetic field strength, B=0.50 T.
Substitute the value in the above formula,
Hence, the retarding force on the rod is 75× 10 −3 N.