[填空题]
Estimate the resistance uibnfwu 1e/: p5.4yc yd/yxl/gj/ c .aof the k2(p q4ah8e* zh: ugkk$120-V_{rms}$ circuits in your house as seen by the power company, when
(a) everything electrical is unplugged,
(b) there is a lone 75-W lightbulb burning. $\Omega$
