Important Topics

1. Heat effects of electric currents, uses and applications.

2. Computation of the heat developed in a circuit. Three formulas.

3. Electric lamps; incandescent and arc; construction, uses, efficiency.

Exercises

1. Sketch a circuit containing 10 incandescent lamps in parallel. If each lamp when hot has a resistance of 220 ohms, and the E.M.F. is 100 volts, what current will flow?

2. What will it cost to use these lights for 3 hours a day for 30 days at 10 cents a kilowatt hour?

3. How much heat will these lamps produce per minute?

4. How could you connect 110-volt lamps to a street car circuit of 660 volts? Explain this arrangement and draw a diagram.