In figure below, a conducting rod is pulled to the right with a speed v when a f
ID: 1441982 • Letter: I
Question
In figure below, a conducting rod is pulled to the right with a speed v when a force Fapp is applied. The load resistance R in the circuit is 6.0 ? (ignoring small internal resistance of the rod and rails) and the rail separation l is 1.20 m. A uniform 2.50-T magnetic field is directed into the page. a) At what speed should the bar be moved to produce a current of 0.500 A in the resistor? b) Calculate the applied force required to move the bar to the right at a constant speed of 2.00 m/s. c) At what rate is energy delivered to the resistor in part b? (Answer: a) 1.00 m/s, b) 3.00 N, c) 6.00 W)
Explanation / Answer
current = 0.5A
so emf = 0.5* 6 = 3V
emf = B*l*v
V = 3/2.5*1.2 = 1 m/s
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it has to move with V = 2m/s
so emf = 2.5*1.2*2 = 6V
so current I = 6/6 = 1A
so force = I*L*B = 1 * 1.2*2.5 = 3N
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.power delivered = emf *I = 6*1 = 6W