For You To Do

1. Your teacher will do this part of the activity as a demonstration for the entire class. You will intentionally exceed the load limit of the circuits that supply electricity to your classroom. Observe the number of light bulbs needed to reach the load limit and the manufacturer's ratings of the bulbs.

a) Calculate the load limit of the circuit, in watts. This will apply to the load limit of the circuits for your Homes For Everyone (HFE) dwelling.

2. Knowing that the energy per unit of electric charge supplied to the circuit is 120 V (volts), use the answer to the previous calculation and the equation Power = current 3 voltage (P = IV) to calculate the current, in amperes, that must have been flowing in the circuit when the load limit was reached.

a) Show your calculation in your log. Assume a voltage of 120 V.

b) How much current, in amps, must be flowing through the filament of a 60-W light bulb when it is operating in a 120-V household circuit? A 100-W light bulb? Show your calculations in your log.

c) Fuses and circuit breakers are rated in amperes, usually 15 or 20 A for most household circuits. In your log use the equation P = IV to show how you can calculate the load limit, in watts, of a 120-V household circuit protected by a 15-A circuit breaker.