PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Two horizontal, frictionless conducting rails are 0.40m apart and connected at one end through a resistance of 0.20Ω. A conducting rod of negligible resistance and length equal to the rail separation is pulled along the rails with a constant speed of 3.0m s−1 by an external force directed to the right. A uniform magnetic field of 0.50T is directed vertically downward.
(a) Calculate the magnitude and state the direction of the induced current in the circuit.
(b) Determine the magnitude of the force that must be exerted on the rod to keep its speed constant.
(c) Compute the electrical power dissipated in the resistor and show that it equals the mechanical power delivered by the applied force.