Problem 30.2: Switched light bulbs

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The circuit shown contains three lightbulbs, an ideal battery, and a variable resistor. Answer the following questions by varying the resistance and examining the current and voltage across each circuit element (voltage is given in volts, current is given in amperes, and resistance is given in ohms). Restart.

  1. As you change the resistance, what happens to bulbs A, B, and C?
  2. Why doesn't the brightness of bulb C change?
  3. Why do the currents change in the way that they do?
  4. Is the voltage of the battery changing? Why or why not?
  5. Why do the voltages across the bulbs change the way that they do?

Problem authored by Anne J. Cox.