Electromagnetism

1. Chapter 18 Electromagnetism Preview CRCT Preparation

2. CRCT Preparation Chapter 18 1. The table shows the number of primary and secondary coil loops in four transformers. Which of the four transformers decrease current? AA and C BB and C CB and D DA, B, C, and D

3. CRCT Preparation Chapter 18 1. The table shows the number of primary and secondary coil loops in four transformers. Which of the four transformers decrease current? A A and C BB and C CB and D DA, B, C, and D

4. CRCT Preparation Chapter 18 2. Which of the four transformers are step-down transformers? AA and C BB and C CB and D DA, B, C, and D

5. CRCT Preparation Chapter 18 2. Which of the four transformers are step-down transformers? AA and C BB and C C B and D DA, B, C, and D

6. CRCT Preparation Chapter 18 3. In which of these locations would you find power lines with the highest voltage? Ain a neighborhood Bleaving a power distribution center Cleaving a power plant Dentering a house

7. CRCT Preparation Chapter 18 3. In which of these locations would you find power lines with the highest voltage? Ain a neighborhood Bleaving a power distribution center C leaving a power plant Dentering a house

8. CRCT Preparation Chapter 18 4. An electromagnet used in a junkyard can only pick up cars. How could the electromagnet be improved so that it could lift trucks and other large vehicles? A The electric current and the number of coils in the solenoid could be increased. B The electric current could be increased and the number of coils in the solenoid could be decreased. C The electric current and the number of coils in the solenoid could be decreased. D The electric current could be decreased and the number of coils in the solenoid could be increased.

9. CRCT Preparation Chapter 18 4. An electromagnet used in a junkyard can only pick up cars. How could the electromagnet be improved so that it could lift trucks and other large vehicles? A The electric current and the number of coils in the solenoid could be increased. B The electric current could be increased and the number of coils in the solenoid could be decreased. C The electric current and the number of coils in the solenoid could be decreased. D The electric current could be decreased and the number of coils in the solenoid could be increased.

10. CRCT Preparation Chapter 18 5. Catherine rubs an iron nail in one direction with the south pole of a magnet. Which of the following is true of the magnetized nail? A It will only be attracted to the north pole of a bar magnet. B It has a strong north pole and a much weaker south pole. C Its domains have become rearranged so that they line up in one direction. D The bar magnet has caused a random arrangement of the nail’s domains.

11. CRCT Preparation Chapter 18 5. Catherine rubs an iron nail in one direction with the south pole of a magnet. Which of the following is true of the magnetized nail? A It will only be attracted to the north pole of a bar magnet. B It has a strong north pole and a much weaker south pole. C Its domains have become rearranged so that they line up in one direction. D The bar magnet has caused a random arrangement of the nail’s domains.

12. CRCT Preparation Chapter 18 6. An electric outlet in the United States provides 120 volts of alternating current. An electric outlet in England provides 230 volts of alternating current. What kind of device would you need in order to use your hair dryer in a hotel in England? Aa galvanometer Ba solenoid Ca commutator Da step-down transformer

13. CRCT Preparation Chapter 18 6. An electric outlet in the United States provides 120 volts of alternating current. An electric outlet in England provides 230 volts of alternating current. What kind of device would you need in order to use your hair dryer in a hotel in England? Aa galvanometer Ba solenoid Ca commutator D a step-down transformer

14. CRCT Preparation Chapter 18 7. When a current-carrying wire is placed between two poles of a magnet, the wire jumps up, as shown in the diagram. Which of the following statements about this phenomenon is true? AThe wire creates a magnetic field that interacts with the magnetic field of the magnet. BThe north pole of the magnet interacts with the south pole of the wire. CThe battery transfers its magnetic field to the wire. DThe wire causes the domains of the magnet to rearrange.

15. CRCT Preparation Chapter 18 7. When a current-carrying wire is placed between two poles of a magnet, the wire jumps up, as shown in the diagram. Which of the following statements about this phenomenon is true? A The wire creates a magnetic field that interacts with the magnetic field of the magnet. BThe north pole of the magnet interacts with the south pole of the wire. CThe battery transfers its magnetic field to the wire. DThe wire causes the domains of the magnet to rearrange.

16. CRCT Preparation Chapter 18 8. Jane puts the north pole of a bar magnet near an object on her desk. As the magnet gets closer to the object, the object is repelled and moves away from the magnet. Which of the following statements about the object on Jane’s desk is true? AThe object has a north pole but no south pole. BThe object is a magnet or has been magnetized. CThe object has randomly-arranged domains. DThe object is not made of metal.

17. CRCT Preparation Chapter 18 8. Jane puts the north pole of a bar magnet near an object on her desk. As the magnet gets closer to the object, the object is repelled and moves away from the magnet. Which of the following statements about the object on Jane’s desk is true? AThe object has a north pole but no south pole. B The object is a magnet or has been magnetized. CThe object has randomly-arranged domains. DThe object is not made of metal.

18. CRCT Preparation Chapter 18 9. Elise tells her friends that Earth’s magnetic field is created by a giant bar magnet at Earth’s center. Is she right? Explain your answer.

19. CRCT Preparation Chapter 18 9. Answer – Although Earth does act like a giant bar magnet, the temperature of Earth’s core is too high to maintain aligned domains. As Earth rotates, the magnetic field is generated by electric charges that move within Earth’s core.

20. CRCT Preparation Chapter 18 10. Dennis is building a toy car. He is trying to decide whether to install an electric generator or an electric motor to power the toy. Which should he choose? Explain your answer.

21. CRCT Preparation Chapter 18 10. Answer – Dennis should install the electric motor. Electric motors convert electrical energy into mechanical energy that is required to make the car move. Electric generators convert mechanical energy into electrical energy, which would not be useful in the toy.