Why is Voltage across resistor zero and voltage across capacitor equal to source in DC voltage?

Question

We are considering an RC series circuit and the voltage source is a DC voltage source

Answer 1

Look at the terminology. "Voltage" is a silly term. It would be like calling force "Newtonage". What voltage actually is is POTENTIAL.

There is no potential across the resistor because there is no accumulation of electrons. A capacitor, however, accumulates an excess of electrons on one terminal, and a deficit on the other terminal. The magnitude of this excess/deficit is the potential, or voltage.

The reason it's equal to the source is easy. A 9V battery has a voltage/potential of 9V across it's terminals. When a perfect conductor is introduced between the two, potential drops to zero, as electrons are free to move as they please. If you introduced a capacitor, the potential across it would slowly build until it reached 9V. Since the maximum potential of the battery is 9V, that's the greatest potential it can induce in a circuit.

Here's an easier (and more correct) way to think of it. A capacitor does NOT store electrons. It simply holds them back, like a water gate. When the gate opens, (a lesser potential elsewhere in the circuit), the water passes through the gate until all the force is balanced.

Answer 2

after the capcitor has charged up (consider the time constantof te RC circuit) then there is no more current flow. If there is no current then the voltage drop across the resistor, v=ir, i=0. if there is no drop across the resistor, then it must be all dropped across the capacitor, the only other component in the circuit

Answer 3

The voltage across a resistor is never zero( unless its just lying on the table of course.)

In a circuit, both capacitors and resistor have voltage drops. A capacitor is like a water tower and stores a little bit of electricity. A resistor is like a water fall and turns electricity into heat or work. It's really not quite that simple ,but here is my favorite website on the subject--
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

Answer 4

There is no voltage across the resistor because no current flows after the capacitor is charged.

Answer 5

you are talking about a steady state suituation. because when u connect the RC circuit there will be a current flowing.
at steady state there is no current flow, the capacitor is fully charged, and its potential difference value is that of the battery.
hope this answered ur question