8 a 1 This can either be an extremely easy calculation, or an ex- tremely difcult question. If you are clever in your choice of loop, it can be solved in one line with no algebra! RC Circuits e. [um] ta'i'fw Which of the following statements are true? Select all cor- rect. If none correct, enter N. A) The time constant for a discharging capacitor is larger than for a charging capacitor. B) The time constant 13(1/2} is the time it takes a charging capacitor to reach 50 C) When we charge a capacitor, the current is initially small and gets larger with time. D) When we discharge a capacitor, the current is initially large and gets smaller with time. E) The potential drop across an uncharged capacitor is V/R. F) The time constant T = RC is the time it takes a charging capacitor to reach 63 LIE R C l I 2R I 16 lItIuI 0N4:- Potential Difference (V) MIA-0100 0 4 8 12 16 Time (1115) Use the graph to determine the capacitance of the circuit. 13. 1 t iii? [pl I 0' Find the time constant for charging 1- 8 the capacitors in the circuit shown. C = 117.0 HF and R = 291.0 9. \\I 30 Note: This question and its values have been updated to re solve a mistake. We apologize for this inconvenience. Please use your new values when solving now. R Hint: To solve this, you must rst nd the equivalent ca pacitance of the circuit! The capacitor in the circuit shown is charged for a long time by a battery with & = 8 V, with the switch in contact with terminal b. C = 14mF, and R = 200 0. R C 9. [ 1pt ] Aww With the switch in position b, what is the absolute potential difference between the plates of the capacitor? 10. [1pt] Aww Determine the time constant, 7, of the circuit when the switch is moved to terminal a. 11. [1pt] * *w If the switch makes contact with terminal a at t = 0s, what is the current through the resistor at t = 570 ms? 12. [1pt] * * * The switch in the RC circuit shown is closed at t = 0s. The plot shows the potential difference across the capacitor as a function of time. R = 2500 0.7. [1a] iii The circuit below contains eight resistors and two batteries with 81 = 9V and 52 = 8V. What is the change in potential across the resistor R? Remember that you can choose any closed path for your current loop. The circuit shown is powered by a battery with & = 15 V. R1 = 10 02, R2 = 25 02, and R3 = 310. Solve the following problems by using Kirchhoff's laws. They may also be solved using Ohm's Law and the concept of equivalent resistance. That will not be the case for the Recommended and Optional Problems. WW R2 E R R 3 1. [1pt ] * wx Find the change in potential across R1. 2. [1pt] Aww What current flows through R3? 3. [1pt] Aww Calculate the drop in potential across R3. 4. 1pt] * * * Consider the circuit shown, with 61 = 9V, 62 = 4V, R2 = 2k0, and R3 = 3k0. Determine the currents I1, I2, and 13. Input your answers in this order. 12 13 R2 E1 R3 82 Find I1: 5. [1pt] * ** Find 12: 6. [1pt] * * * Find I3