Answer
a. 160$\Omega$, 0.68 A
b. 48$\Omega$, 2.3 A
Work Step by Step
a. Use equation 18–6b to calculate the power, and solve for the resistance R.
$$P=\frac{V^2}{R}$$
$$R=\frac{V^2}{P}=\frac{(110V)^2}{75W}=160\Omega$$
Use equation 18–5 to calculate the power, and solve for the current I.
$$P=IV$$
$$I=\frac{P}{V}=\frac{75W}{110V}=0.68A$$
b. Use equation 18–6b to calculate the power, and solve for the resistance R.
$$P=\frac{V^2}{R}$$
$$R=\frac{V^2}{P}=\frac{(110V)^2}{250W}=48\Omega$$
Use equation 18–5 to calculate the power, and solve for the current I.
$$P=IV$$
$$I=\frac{P}{V}=\frac{250W}{110V}=2.3A$$
