Please answer parts A and B in the link. Thanks! http://i.imgur.com/YPZqCdY.png
ID: 1438558 • Letter: P
Question
Please answer parts A and B in the link. Thanks! http://i.imgur.com/YPZqCdY.png A single conducting loop of wire has an area of 8.0 times 10^-4 m^2 and a resistance of 110 H. Perpendicular to the plane of the loop is a magnetic field of strength 0.18 T. At what rate (in T/s) must this field change if the induced current in the loop is to be 0.19 A? A magnetic field increases from 0 to 0.13 T in 2.1 s. How many turns of wire are needed in a circular coil 12 cm in diameter to produce an induced emf of 6.6 V?Explanation / Answer
A.
Emf = I*R = 0.19*110 = 20.9 V
Also Emf = N*d(phi)/dt
phi = B*A*cos X
Emf = N*d(B*A*cos X)/dt
N = 1 and X = 0
EMF = (-dB/dt)*A
dB/dt = -20.9/(8*10^-4) = -26125 T/sec
B.
EMF = N*A*cos X*dB/dt
N = EMF/(A*cos X*dB/dt)
N = 6.6/(3.14*0.06^2*1*0.13/2.1) = 9431.65 = 9432 turns