SNC1D
Test Review: Electricity
Topics:
1. Laws of static charge (attraction/repulsion)
2. How to charge by friction, conduction and induction.
3. Using the electrostatic series to predict charges of insulators.
4. Uses and differences between insulators and conductors
5. Electroscopes and how they work to show an object is charged.
6. Calculations involving the four triangle (power (P), energy (E), current (I), potential difference (V), resistance (R), time (t))
7. Circuit diagrams
8. Series and parallel circuit calculations.
Review Questions:
1. Explain why "static cling" does not develop when a clothes dryer is used to dry a load consisting only of cotton towels. Write your answer in complete sentences.
2. Explain what happens when a negatively charged pith ball hanging from a string is brought close to a neutral pith ball also hanging from a string.
3. Explain the difference between a conductor and an insulator with respect to the electrons within. Give examples of each.
4. Cat's fur will lose electrons to copper more readily than it will lose electrons to ebonite. Since this is true, explain why you cannot use fur to build up a static electric charge on a copper rod held in your hand but you can use the fur to build up a static electric charge on an ebonite rod held in your hand. Write your answer in complete sentences.
5. Describe how one would give an electroscope a negative charge by:
a. Conduction
b. Induction
6. Is it possible to charge a rubber balloon via conduction? Why or why not?
7. Explain how to charge a metal leaf electroscope negatively by induction.
8. Draw possible diagrams for each of the following circuits:
a. Two resistors in series, powered by a 9V source and containing a switch before the resistors.
b. Three resistors in parallel with a 6V power source. One voltmeter is attached to measure the potential difference of the resistors and three ammeters are attached so that the current through each resistor is measured.
9. Calculate the power of a laptop computer that draws 3.0 A from a 7.5 V battery.
10. A CD changer, drawing 11 A, operates for 5.0 h in a 120-V circuit. Calculate how much electrical energy is required.
11. An electric stove draws 20.8 A of current in a 240-V circuit. Calculate how much electrical energy it uses while cooking a roast for 2.5 h.
12. A 3000 W stove element is left on for 1.5 hours. The stove transferred 51,000 kJ of energy to a pot of chili during that time. What is the efficiency of the element?
13. List three renewable sources of electrical energy and three nonrenewable sources of electrical energy.
14. It is said that the source of energy for hydroelectric dams ultimately comes from the sun. Explain why this is true.
15. A meter reader determines that a business has used 3550 kWh of energy in two months. If electricity costs 10 cents per kWh, calculate the bill.
16. A toaster is used an average of 5 h a month. The toaster draws 8 A of current from a 110 V outlet. If electricity costs 8 cents per kWh, how much will it cost to operate the toaster for one year?
17. Consider the circuit drawn below:
a. What are the values for IS, R1, R2, and V2?
b. What is the equivalent resistance, Req, of the circuit?
18. Consider the diagram of the circuit below:
a. Calculate the values for VS, R2, I3, V3, R3, I4, and V4.
b. Calculate the equivalent resistance, Req, of the circuit.
Text Questions:
p. 588-592 #1, 3-15, 54-64, 65-73, 75-76