Consider and odd short of hand-shaken generator; see figure. The generator consi
ID: 1436027 • Letter: C
Question
Consider and odd short of hand-shaken generator; see figure. The generator consists of a coil on a short track. The Coil is rectangular and has width W and length L; he coil has N turns. It can slide freely back and forth on the track, which has length 2L. The right half of the track is between the poles of a magnet and has a uniform magnetic field of strength B perpendicular to the track. The other half of the track has no field. The generator is operated by shaking the assembly, making the coil slide from one end of the track to the other in alternation, passing into and then out of the field. The generator is shaken with frequency f, i.e., the coil slides from the left end of the track to the right end and back, f times a second. Assuming the coil moves at a uniform speed, derive a relation for the EMF E(t) produced by this generator, in terms of N, W, L, B, and f. Make a sketch graph of E(t) over one full cycle of the generator. Evaluate the generator with a hand-held unit's dimensions: W=L=2 cm, B=o.1 t, N=1000, and f=3 Hz. If the voltage drives current through a 1.5 resistor, what is the electrical power generated?Explanation / Answer
Emf = rate of change of magneric flux
=NBW dL/dt = NBW(2Lf) = 2NBWLf while going into field
-2NBWLf while coming back from the field
b)Emf = 2NBWLf = 2*1000*0.1*2*2*3 = 2400 V
Power = V2/R = 2400*2400/1.5 = 3840000 Watt = 3.84 megawatt