1.
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.
2.
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.
Adding a resistor in parallel decreases the effective resistance of a circuit.
Using I=V/R, the current through the battery will increases.