Answer
(a) $I_0 = 4.0~A$
(b) $I_0 = 4.0~A$
(c) $I_0 = 4.0~A$
Work Step by Step
We can write an expression for the current:
$I_0 = \frac{emf_0}{R} = emf \cdot \omega~C$
(a) If the capacitance is doubled then the peak current is increased by a factor of $2$
$I_0 = 4.0~A$
(b) If the peak emf is doubled then the peak current is increased by a factor of $2$
$I_0 = 4.0~A$
(c) If the frequency is doubled then the peak current is increased by a factor of $2$
$I_0 = 4.0~A$
