Physics 2

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Practice Problems: RC Circuits

1. (easy) A 200Ω resistor, a 5000μF capacitor, a switch, and a 10 v battery are in series in a single circuit loop. Determine the initial and steady state currents. How long wiil the circuit take to reach steady state (approximately).

2. (easy) A pair of 2 F capacitors (in parallel) is in series with another pair of 1 F capacitors (in parallel). What is the equivalent capacitance of this configuration?

3. (moderate) Analyze the circuit below to find the following:
a. The current in the loop after three time constants
b. The energy stored in each capacitor at steady state 4. A capacitor (C = 3.2x10-7 F) is charged as electrons move from one plate to the other to achieve a potential difference of 500 v. How many electrons were moved in order for the capacitor to achieve this charge?

5. (moderate) Analyze the circuit below to find the charge stored on each capacitor at steady state. Additionally, find the ammeter reading at 3.0 milliseconds. 6. (moderate) A 3 μF (air-filled) capacitor is connected to a 12 volt battery. Calculate the amount of energy is stored in the E-field. Additionally, If a piece of polystyrene (k = 2.56) is inserted into the capacitor, how much energy will remain in the E-field? Why does it decrease? During the insertion of the dielectric material, will it feel an attraction for the plates or a repulsion?