Answer
a. 20
b. $3.3\times10^{-2}$
Work Step by Step
a. Use equation 21-6 to find the turns ratio.
$$\frac{N_S}{N_P}=\frac{V_S}{V_P}$$
At the power plant, the voltage is stepped up from 12,000 V to 240,000 V.
$$\frac{N_S}{N_P}=\frac{240000}{12000}=20$$
b. Use equation 21-6 to find the turns ratio.
$$\frac{N_S}{N_P}=\frac{V_S}{V_P}$$
At the house, the voltage is stepped down from 7200 V to 240 V.
$$\frac{N_S}{N_P}=\frac{240}{7200}=\frac{1}{30}=3.3\times10^{-2}$$
