Question: A generator uses a coil that has 100 turns and a 0.50-T magnetic field. The frequency of this generator is 60.0 Hz, and its emf has an rms value of 120 V. Assuming that each turn of the coil is a square (an approximation), determine the length of the wire from which the coil is made.
My Approach: I used the equation E = NABw(1/sq(2)). I solved for w using w = 2(pi)f. Plugged all the values into the equation and got A = .009 m^2.
This is where I’m stuck…After solving for the side of the square A = s^2 using .009 m^2 (area that was figured), I came up with s = .095 m. How can I figure the L-value??? I’m STUCK here!
Book Answer = 38 m
22. May 2010 at 1:33 pm
Hi, Jim.
You’ll probably be surprised, but you got the problem solved already. I’ve checked your work, and it is correct. Indeed, A = 0.009 m², and s = √A = 0.095 m. Just recall the coil has 100 turns, and the square has 4 equal sides. Four times 0.095 gives 0.38 m, the lenght of each turn. Multiplying by 100, that’s 38 m, the book answer.
Regards.