SNC1D SNC1D Electricity Unit Review

For a list of the topics you are responsible for, see the Electricity Learning Goals and Success Criteria sheet!

Practice Problems: 1. State the three subatomic particles and describe their location and charge. 2. What type of charge moves through a circuit? 3. State the points of the Law of Electric Charges. 4. Determine the charge difference between the following pairs of objects and explain which will have the greatest attraction. a) b) c)

5. Define insulator and provide two examples of insulators. 6. Define conductor and provide two examples of conductors. 7. Joey’s younger brother is playing with a plastic toy and decides to stick it into an uncovered wall outlet. Joey is worried that he will get a shock, but surprisingly, he doesn’t. Explain why his younger brother did not get shocked. 8. Define static electricity and static discharge. 9. Describe the electric field of charged objects. 10. Provide one example of how static can affect our everyday lives. Explain what is happening. 11. What is charging by friction in your own words? Be specific. 12. If a wool sweater is pulled over a cotton shirt and they rub together explain what will happen. Identify the charge that each material receives, how you know they receive this charge, what type of charging has occurred, and how the materials will behave near one another after charging has occurred. 13. Describe charging by contact. 14. A positively charged rod touches the knob of a neutral electroscope. Describe what will happen to the leaves and explain why with detail. 15. Describe what happens when a charged object comes close to (but does not touch) a neutral object. What is this process called? When the charged object moves away what happens? 16. A negatively charged rod comes close to a neutral object (no contact is made). Describe what will happen to the object. Discuss the movement of charges in your answer. 17. What three factors affect static discharge? 18. How can we deliver the largest shock to John Travoltage keeping these three factors in mind? 19. Define current electricity. 20. Compare and contrast direct current and alternating current. 21. What are the three required components for a complete simple circuit? 22. Define Coulomb, current, potential difference (voltage), and resistance. Include the units and symbol for each. 23. Complete the following table.

Unit of Measurement Term Electrical Quantity Symbol Unit of Measurement Symbol Quantity of charge Current SNC1D SNC1D Electricity Unit Review Potential difference (Voltage) Energy Resistance Term Electrical Quantity Symbol Unit of Measurement Unit of Measurement Symbol Power Time

24. State Ohm’s law using words and in the form of an equation. What are the three math equations for Ohm’s Law? 25. A flashlight powered by a 6 V battery draws a current of 2 A. What is the resistance of the bulb? Use GRASP to solve. 26. A hair dryer has a resistance of 15 Ω. What current will it draw if it is powered by a 120 V source? Use GRASP to solve. 27. What instrument is used to measure current. How is it connected to measure the current in a circuit? 28. What instrument is used to measure voltage? How is it connected to measure the voltage in a circuit? 29. What does it mean for two loads to be connected in series? What does it mean for them to be connected in parallel? Use diagrams to support your answer. 30. Draw a series circuit that has a 10 V power source, a resistor, and a light bulb. Both the loads are turned on. An ammeter is reading the current of the circuit. Indicate the direction of flow. 31. Draw a parallel circuit with three branches. The power source in the main branch is a three dry cell battery. A bulb is in branch one, a resistor in branch two and a motor in branch three. The bulb is switched off; the other loads are switched on. A voltmeter is reading the voltage across the resistor. 32. Discuss how type of material, cross-sectional area, length and temperature affect the resistance of a wire. 33. Make a statement regarding the relationships of current, voltage and resistance in a series circuit.

Include a formula for each. (i.e. IS = , VS = , R = , P = ) 34. Make a statement regarding the relationships of current and voltage in a parallel circuit. Include a

formula for each. (i.e. IS = , VS = ) 35. Solve the following circuits:

36. A 60 W incandescent bulb and a 14 W CFL bulb both put out 108,000 J of light energy in one hour. Use the GRASP problem-solving method to complete the following questions. a) Calculate the percent efficiency of the 60W bulb if it uses 2,160,000 J of electrical energy. b) Calculate the percent efficiency of the 14W CFL bulb if it uses 540,000 J of electrical energy. c) Why is the incandescent bulb less efficient? SNC1D SNC1D Electricity Unit Review 35. A regular light bulb (incandescent) has a power rating of 0.1 kW (100 W bulb). If the bulb is left on for three hours every day for one year (365 days), how much will it cost to power this bulb if the cost is 8.8 ¢/kW·h? Use the GRASP problem-solving method.