Answer
(a) $P = 2.0~W$
(b) $P = 16~W$
(c) $P = 8.0~W$
Work Step by Step
We can write an expression for the average power:
$P = \frac{\epsilon_0^2}{2R}$
(a) If the resistance $R$ is doubled, then the power decreases by a factor of $\frac{1}{2}$
$P = 2.0~W$
(b) If the peak emf $\epsilon_0$ is doubled, then the power increases by a factor of $4$
$P = 16~W$
(c) If both the resistance $R$ and peak emf $\epsilon_0$ are doubled, then the power increases by a factor of $2$
$P = 8.0~W$
