A circuit contains a 6.0-V battery,a 4.0-Ω resistor,a 0.60-µF capacitor,an ammeter,and a switch all in series.What will be the current reading immediately after the switch is closed?
A)zero
B)0.75 A
C)1.5 A
D)10 A

Question

A circuit contains a 6.0-V battery,a 4.0-Ω resistor,a 0.60-µF capacitor,an ammeter,and a switch all in series.What will be the current reading immediately after the switch is closed? 
A)zero 
B)0.75 A 
C)1.5 A 
D)10 A

Quizplus · Accepted Answer

Before the switch is closed, the capacitor is uncharged and behaves like an open circuit. Therefore, initially the current is zero. When the switch is closed, the capacitor starts to charge and begins to act like a resistor, but with an increasing resistance as it charges. However, at the instant when the switch is closed, the capacitor behaves like a short circuit and the circuit becomes a simple series circuit with a 6V battery and a 4Ω resistor, so the current is I = V/R = 6V/4Ω = 1.5A. Therefore, the correct answer is choice C.

A Circuit Contains a 6