Chapter 18 - D.C. Circuits


Explain why electric lights in a building are connected in parallel rather than in series.

  • When the bulbs are connected in parallel, the current through each bulb will be higher and hence each bulb will glow more brightly.

  • Parallel arrangement also allows the bulbs to work independently. That is, when one bulb is fused or blown, the other bulbs can still work.


Resistor A and B are in parallel. Would the addition of an extra resistor parallel to A and B increase or decrease the current flowing through the battery? Explain your answer.

resistors in parallel
  • Adding a resistor in parallel decreases the effective resistance of a circuit.

  • Using I=V/R, the current through the battery will increases.