Answer
See answers.
Work Step by Step
a. Find the current in the transmission lines from Eq. 18–9a.
$$I_{rms}=\frac{P_{town}}{V_{rms}}=\frac{35\times10^6 W}{45\times10^3 V}=778A$$
Use Kirchhoff’s loop rule to calculate the rms value of the emf, at the generator end of the lines.
$$\epsilon-IR+V_{output}=0$$
$$\epsilon=IR+V_{output}=(777.77A)(4.6\Omega)+45\times10^3 V=49kV$$
b. The power dissipated in the lines is lost as heat, $P_{lost}=I^2_{rms}R$.
Calculate the fraction wasted.
$$f=\frac{P_{lost}}{ P_{lost}+ P_{delivered}}=\frac{(777.77A)^2(4.6\Omega)}{ (777.77A)^2(4.6\Omega)+35\times10^6 W}=0.074$$
