Review: Magnetism and Electromagnetism

Transcription

1 Review: Magnetism and Electromagnetism Multiple Choice: Write the letter of the term or phrase that best completes each statement. 1. Magnetism is a force of a. gravity. b. weight. c. voltage. d. attraction or repulsion. 2. The magnetic lines of force are closest together at a magnet's a. poles. b. north pole. c. south pole. d. middle. 3. An electric appliance needs a motor to change electrical energy into a. heat energy. b. mechanical energy. c. chemical energy. d. light energy. 4. An electromagnet is a. a permanent magnet. b. a temporary magnet. c. a weak magnet. 5. Of the following examples, the one that will make an electromagnet with the strongest magnetic field is a a. wire with four coils. b. straight wire. c. wire with three coils. d. wire with two coils. 6. Of the following items, the one that would be attracted to a magnet is a. an iron bar. b. a glass jar. c. a wooden toothpick. d. a plastic cup. 7. When a material, such as an iron nail, is made into a magnet, magnetism has been a. destroyed. b. strengthened. c. weakened. d. induced. 8. When the north and south poles of two magnets are facing each other, they a. attract each other b. repel each other c. have no effect on each other d. magnetize each other. 9. One way to increase the strength of an electromagnet is to a. increase the resistance of the wire. b. Decrease the current in the wire. c. Increase the current in the wire. 10. All magnetism is created by: a. Natural magnets. b. Movement of charges. c. Current carrying wires. 11. Which of the following will experience a force in a magnetic field? a. A magnet. b. A stationary charge. c. A moving charge. d. A and C. 12. You take a permanent magnet and break it in half. You now have: a. Two magnets, each with its own North and South pole. b. One chunk of North and one chunk of South.

2 Vocabulary Matching: Match the key term in the column on the right with its definition on the left. 1. Device that changes mechanical energy into electrical energy. 2. Process by which a material can be made into a magnet 3. Temporary magnet made by wrapping a current-carrying wire around an iron core 4. Force of attraction or repulsion by magnetic materials. 5. Region of Earth s magnetic field 6. Lines that show the shape of a magnetic field 7. Two ends of a magnet 8. Device that changes electrical energy into mechanical energy 9. Area around a magnet where magnetic forces can act. 10. The relationship between electricity and magnetism. 11. Groups of atoms whose magnetic poles are all lined up in the same direction. 12. A tool that uses magnetism to aid in navigation. A. Compass B. Electric Generator C. Electric Motor D. Electromagnet E. Electromagnetism F. Magnetic Domain G. Magnetic Field H. Magnetic Induction I. Magnetic Lines of Force J. Magnetism K. Magnetosphere L. Pole

3 Decide which is the stronger electromagnet in each figure, A or B. Write your answers in the spaces provided Skill Challenge Skills: analyzing, modeling Choose one of the statements listed below. In the space provided, draw a diagram that illustrates the statement. 1. A coil of wire has a stronger magnetic field than a straight wire. 2. Electromagnets have many important uses. 3. An electromagnet can be made stronger in two different ways. 4. An electromagnet can be turned on and off. 5. The center of an electromagnet is called a core.

4 Skill Challenge Skills: locating, observing Look at the drawing of Earth. Label the geographic North Pole and South Pole. Then, label the magnetic south pole and the magnetic north pole. Draw in the magnetosphere. Lesson Review Determine if each item listed will be attracted to a magnet or not affected by a magnet. Write attracted or not affected in the spaces provided. 1. wooden chair 2. iron kettle 3. paper clip 4. milk carton 5. glass jar 6. refrigerator 7. bar of cobalt 8. nickel coin 9. metal filing cabinet 10. window glass

5 Open Response Question: BE SURE TO ANSWER AND LABEL ALL PARTS OF EACH QUESTION. The picture below shows five ring magnets that are stacked around a pencil. When the pencil is held upright, the magnets do not touch, but appear to be suspended in the air. When the magnets are pushed closer together, they quickly return to their original positions. a. Explain why the magnets are not touching each other and appear to be suspended in air. b. Describe what would happen if the pencil were taken away. The magnets were then rearranged so they stacked around the pencil as shown below. c. Explain how the magnets were rearranged on the pencil so that they stacked directly on top of each other as shown. d. Describe what would happen if the pencil were taken away.

6 MCAS Multiple Choice 1. Which set of magnets shown to the right will be attracted to each other? 2. The diagram to the right represents two bar magnets. Which of the diagrams to the right shows the effect of magnetic energy on the magnets as the two magnets above are moved closer together? 3. In which case would it take the most effort to make points 1 and 2 on the magnets touch each other?