Step response of a RC circuit asking for i(t)

[danielerbe]

Homework Statement

In attachment

Homework Equations

i don't understand why it would be asking for the current going through the capcitor, in a dc circuit it should be an open circuit but there will be a voltage over it... after searching through lecture notes and textbook can't find anything relating to I(t) in a RC DC circuit.
could anyone point me in the direction of a recourse that will explain this to me or give me some idea about what the qestion is asking?... thanks in advance.

 

[Andrew Mason]

Homework Statement

In attachment

Homework Equations

i don't understand why it would be asking for the current going through the capcitor, in a dc circuit it should be an open circuit but there will be a voltage over it... after searching through lecture notes and textbook can't find anything relating to I(t) in a RC DC circuit.
could anyone point me in the direction of a recourse that will explain this to me or give me some idea about what the qestion is asking?... thanks in advance.

When the applied voltage changes, there is a brief current that depends on the value of R and C. What is the charge in the capacitor with the 30 V battery connected? What happens to the charge when that battery is removed and the 12V battery is connected? Since there is a change in charge what is dQ/dt?

AM