Field and Wave Electromagnetics 2nd Edition by David Cheng

Exercise 61

A conducting circular loop of a radius 0.1 (m) is situated in the neighborhood of a very long power line carrying a 60-(Hz) current, as shown in Fig., with d = 0.15 (m). An a-c milliammeter inserted in the loop reads 0.3 (rnA). Assume the total impedance of the loop including the milliammeter to be 0.01 ( ).
a) Find the magnitude of the current in the power line.
b) To what angle about the horizontal axis should the circular loop be rotated in order to reduce the milliammeter reading to 0.2 (mA)
FIGURE 1: Suggested eddy-current power-loss reduction scheme (Problem P.7-6).
(a)

FIGURE 2: Suggested eddy-current power-loss reduction scheme (Problem P.7-6).
(b)

FIGURE 3: A long, straight wire and a conducting circular loop (Problem P.6- 39).