A generator uses a coil that has 140 turns and a 0.61-T magnetic field. The freq
ID: 2278169 • Letter: A
Question
A generator uses a coil that has 140 turns and a 0.61-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.
A generator uses a coil that has 140 turns and a 0.61-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.Explanation / Answer
120Vrms = 120*1.414 V peak = 169.7 Vpk
So the area of each coil is A = 169.7V / (2pi * 60Hz * 140turns * 0.61T) = 0.00527 m^2
So each turn of the coil is sqrt(.00527) m square = 0.073m * 0.073m
So the total length of wire is 4*0.073m per turn * 140 turns = 40.667 m (3 s.f.)