Ques:

A 12 volt battery is associated in series with an initially-uncharged 120 microfarad capacitor and a 25 ohm resistor. What is the current during the resistor at the instant the connection is made?

Ans:

Just for an immediate subsequent to the connection is made but before any charge has built up on the capacitor the capacitor "acts like" a piece of wire. Therefore for that instant only it is as if the battery in the given circuit is connected across the resistor. Therefore for that instant the resistor voltage is the battery voltage. Utilizing the battery voltage in V=IR and solving for I we find that I = 0.48 A.