How do dielectrics work to increase capacitance?
1. Polarization: Molecules align with the electric field, creating an opposing field. 2. Reduced Electric Field: Net electric field is reduced. 3. Increased Capacitance: More charge can be stored at the same voltage.
Describe the process of charging a capacitor in an RC circuit.
Current flows into the capacitor, voltage across it increases over time, and the current decreases exponentially as the capacitor charges.
Describe the process of discharging a capacitor in an RC circuit.
Current flows out of the capacitor, voltage across it decreases over time, and the current decreases exponentially as the capacitor discharges.
What are the key differences between capacitors in series and parallel?
Series: 1/C_total = 1/C_1 + 1/C_2 + ... , Charge is the same, Voltage adds. | Parallel: C_total = C_1 + C_2 + ... , Voltage is the same, Charge adds.
Compare and contrast the behavior of a capacitor at t=0 and at steady state in a DC circuit.
At t=0: Capacitor acts like a short circuit, allowing maximum current flow. | At steady state: Capacitor acts like an open circuit, blocking current flow.
Compare charging and discharging in an RC circuit regarding current and voltage.
Charging: Current decreases exponentially, Voltage increases exponentially. | Discharging: Current decreases exponentially, Voltage decreases exponentially.
What is the effect of increasing the area of the plates on a parallel plate capacitor?
Increases the capacitance (C = ฮตโA/d).
What is the effect of increasing the distance between the plates of a parallel plate capacitor?
Decreases the capacitance (C = ฮตโA/d).
What happens when a dielectric is inserted between the plates of a capacitor?
The capacitance increases (C = ฮบ(ฮตโA/d)).
What happens to a capacitor in a DC circuit at steady state?
It acts as an open circuit, blocking current flow.
What happens to the energy stored in a capacitor if the voltage across it is doubled?
The energy stored quadruples (U = 1/2 CVยฒ).
