Common Exam II – Monday October :30pm. Exam will cover Chapters 24, 25, 26, 27, and Multi-loop Kirchhoff circuits and RC circuits (today’s material) will NOT be on Common Exam II.

Kirchhoff’s loop laws: NET flow into a junction is zero. For THIS example

Clicker Question #1 What is correct junction equation for the following junction? A) B) C) D) E) None of the above A B C

Clicker Question #2 For the given ASSUMED directions of the currents, what is the loop equation for the TOP loop going clockwise around the loop? A) B) C) D) E) None of the above A B C

When we close switch, how does the charge on the capacitor and the current in the resistor vary in time?

Clicker Question #3 What is true about the light bulb in the following circuit? A) BEFORE the switch is closed, the light is off. When the switch is closed it turns on and stays lighted. B) AFTER the switch is closed the light turns off. It gradually brightens over time. C) AFTER the switch is closed, the light turns on and its brightness increases with time. D) BEFORE the switch is closed, the light is off. When the switch is closed it turns on and slowly dims. E) None of the above A B C

When you close the switch, the charge on the capacitor increases with a characteristic time of τ=RC.

Clicker Question #4 What is the RC time constant for the circuit below? A)0.12 seconds B) 0.15 seconds C) 0.30 seconds D) Can not be determined, it depends on whether you are measuring current or voltage E) None of the above A B C

Clicker Question #5 What is the current in the 3kΩ resistor at t=0.3 seconds? Answer to last question is τ=0.15s. A)Essentially zero. B) 0.6 mA C) 0.22 mA D) 81 µA E) None of the above A B C

Clicker Question #6 If one waits a long time, what is the current in the 12kΩ resistor for the circuit below? A)Essentially zero. B) 0.6 mA C) 0.75 mA D) 0.33 mA E) None of the above A B C