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Main Menu Print Back Name: ________________________ Class: ___________________ Date: __________ ID: A Chapter 20 Multi-format Test Modified True/False Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true. ____ 1. The unit of charge is the ohm. _________________________ ____ 2. An object with equal amounts of positive and negative charge is called electrically neutral. _________________________ ____ 3. A complete path through which electricity travels is called a circuit. ________________________ ____ 4. In many circuit diagrams, any electrical device that uses energy is shown with a resistor symbol. _________________________ ____ 5. A closed circuit has a break in it. _________________________ ____ 6. Differences in electric current cause charge to flow. _________________________ ____ 7. Electric current will flow easily through a insulator. _________________________ ____ 8. An ohm is the unit of measurement for current. _________________________ ____ 9. According to Ohm’s law, resistance is the ratio of voltage to current. _________________________ Completion Complete each statement. Select the correct term to complete each sentence. There are extra terms in the list. voltage drop current static decreases circuit diagram conductors chemical resistance attract increases switch insulators nuclear voltage repel electric charge wire light bulb 10. An tiny imbalance of electric charge on an object causes ____________________ electricity. 11. Two negative charges will ____________________ each other. 12. When we say current is moving through a circuit, we mean ____________________ is moving through the circuit. 13. Short circuits cause the circuit to draw a large amount of ____________________. 14. A shorthand method of describing a real circuit using electrical symbols is called a(n) ____________________. 15. A device used to create an intentional break in a circuit to stop the flow of current is a(n) ____________________. 16. A battery transforms ____________________ energy into electrical energy. 17. A decrease in voltage across a component in a circuit is called a(n) ____________________. 1 Main Menu Print Back Name: ________________________ ID: A 18. Materials through which charge flows easily are called ____________________. 19. Although AAA, AA, C, and D alkaline batteries differ in how long they last, they all have the same initial ____________________. 20. Tungsten is used in light bulb filaments because it glows when hot, rather than melting. The thin tungsten filament gets very hot in a circuit because it has high ____________________. 21. As the temperature of a conductor increases, the resistance of the conductor ____________________. Short Answer 22. Two positively charged objects are separated from each other by 1 centimeter. What is the direction of the electrical force between them? 23. Why are circuit diagrams drawn? 24. To read the voltage, you accidentally connect the positive lead of a voltmeter to the negative terminal of a 1.5 volt battery and the negative lead to the positive terminal. What is the result? 25. You install two batteries in a flashlight so that their positive ends are facing each other. Will the flashlight work? Why or why not? 26. Explain how a potentiometer is different from a fixed resistor. Problem 27. A 120-volt household circuit has a fuse that breaks the circuit if more than 10 amps of current passes through it. What is the minimum amount of resistance in the circuit required to keep the fuse from blowing? 28. If the current moving through the filament of a light bulb is 0.5 amps when the voltage across the bulb is 120 volts, what is the resistance of the bulb? Essay 29. Describe a resistor and its function in a circuit. 2 Main Menu Print Name: ________________________ Back ID: A Other The circuit pictured contains a light bulb connected to a voltage source that causes 2 amps of current through the bulb. Figure 20-2 30. Determine the resistance of the light bulb in Figure 20-2. 3 Main Menu Print Back ID: A Chapter 20 Multi-format Test Answer Section MODIFIED TRUE/FALSE 1. ANS: F, coulomb 2. 3. 4. 5. DIF: ANS: ANS: ANS: ANS: basic T T T F, open REF: section 20.1 DIF: basic 6. ANS: F, voltage REF: section 20.2 DIF: basic 7. ANS: F conductor electrical conductor REF: section 20.3 DIF: basic 8. ANS: F, resistance REF: section 20.3 DIF: basic 9. ANS: T REF: section 20.4 DIF: basic DIF: basic DIF: basic REF: section 20.1 REF: section 20.2 REF: section 20.2 DIF: basic REF: section 20.4 COMPLETION 10. ANS: static DIF: basic 11. ANS: attract REF: section 20.1 DIF: basic REF: section 20.1 12. ANS: electric charge DIF: intermediate 13. ANS: current REF: section 20.1 DIF: basic REF: section 20.2 14. ANS: circuit diagram DIF: basic 15. ANS: switch DIF: basic REF: section 20.2 REF: section 20.2 1 Main Menu Print Back ID: A 16. ANS: chemical DIF: basic 17. ANS: voltage drop REF: section 20.3 DIF: basic 18. ANS: conductors REF: section 20.3 DIF: basic 19. ANS: voltage REF: section 20.3 DIF: basic 20. ANS: resistance REF: section 20.3 DIF: basic 21. ANS: increases REF: section 20.4 DIF: basic REF: section 20.4 SHORT ANSWER 22. ANS: The electrical force between them is a repulsive force, pushing the charges away from each other. DIF: intermediate REF: section 20.1 23. ANS: Circuit diagrams are drawn using symbols to represent the arrangement of components in a circuit because it is easier and quicker than drawing realistic pictures of components. DIF: intermediate REF: section 20.2 24. ANS: The meter reads negative 1.5 volts or, if it is an analog meter, it may be “pinned” (go backwards against a stop). DIF: advanced 25. ANS: REF: section 20.3 The flashlight will not work because the voltage, or potential difference, across the two batteries is zero. Instead of the batteries’ voltages adding together, the voltages subtract from each other. DIF: advanced 26. ANS: REF: section 20.3 A potentiometer can be adjusted to give a range of resistance; a fixed resistor has a resistance that cannot be changed. DIF: intermediate REF: section 20.4 2 Main Menu Print Back ID: A PROBLEM 27. ANS: V 120 volt R= = = 12 ohms I 10 amps DIF: advanced REF: section 20.3 28. ANS: V 120 volts R= = = 240 ohms = 240 Ω I 0.5 amps DIF: intermediate REF: section 20.4 ESSAY 29. ANS: A resistor is an electrical component that is designed to have a specific resistance over a wide range of currents. Resistors are used to control the amount of current in a circuit. DIF: intermediate REF: section 20.4 OTHER 30. ANS: V 1.5 volts + 1.5 volts 3 volts R= = = = 1.5 ohms I 2 amps 2 amps DIF: advanced REF: section 20.4 3 Main Menu Chapter 20 Multi-format Test [Answer Strip] F _____ 1. T _____ 2. T _____ 3. T _____ 4. F _____ 5. F _____ 6. F _____ 7. F _____ 8. T _____ 9. Print Back ID: A