Final answer:
In a household circuit, the connection of light bulbs and appliances affects their operation; bulbs in series versus parallel behave differently when experiencing a break or switch opening, and the brightness is tied to their power ratings and resistance. Holiday lights in series will all go out if one bulb breaks, while modern strands remain lit when one bulb fails. Power companies use high voltage transmission to reduce heat dissipation losses.
Step-by-step explanation:
When considering the connection of light bulbs and appliances to household circuits, it's important to understand basic principles of electricity. For example, regarding how bright bulb A is compared to B and C, the brightness depends on the electrical path and whether the bulbs are in series or parallel. If bulbs are connected in series, they share the same current, so their brightness is typically proportional to their power ratings. If they are in parallel, they get the same voltage, and again, brightness correlates with power ratings.
When a switch S in a circuit containing light bulbs is opened, bulbs that lie in the same path as the switch in series will not light up, as the circuit is broken. However, if connected in parallel, bulbs not in the same path as the switch will remain lit. The current in bulbs A and B would change depending on their circuit configuration. An open switch in a series will cut off the current to both A and B, whereas in a parallel circuit, only the branch with the open switch is affected.
In the case of holiday lights connected in series, if one bulb breaks, making an open circuit, all others go out. However, in modern strands with shunting or short-circuiting bulbs, when one burns out, the rest will stay lit. With older strands of 40 bulbs at 120 V, each bulb operates at 3 V. For newer strands with 39 bulbs remaining, operational voltage per bulb would slightly increase.
When connecting two household light bulbs rated at 60 W and 100 W in series, the one with the higher resistance (which would be the lower wattage bulb if they are designed for the same voltage) will usually be brighter due to a greater voltage drop across it. Finally, power companies transmit electric power at high voltages and step it down using transformers to reduce energy losses to heat dissipation through the wires.