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Chapter Four
Review Questions 1. Which of the following can store energy in the form of an electromagnetic charge? a. Thermocouple b. Induction coil c. Potentiometer d. Capacitor 2. Current flows through a heated thermocouple because of the two-way flow of a. Electrons between dissimilar materials b. The blockage of free electrons between the metals c. The one-way transfer of free electrons between the metals d. Random electron flow 3. Which of the following forms of generating electricity is not widely used in an automobile? a. Heat b. Pressure c. Chemistry d. Magnetism 4. The lines of force of a magnet are called a. Flux lines b. Magnetic polarity c. Magnetic lines d. Flux density 5. A material through which magnetic force can easily flow has a high a. Reluctance b. Permeability c. Capacitance d. Magnetic attraction 6. The left-hand rule says that if you grasp a conductor in your left hand with your thumb pointing in the direction of the electron ( to +) flow, a. Your fingers will point in the direction of the magnetic flux lines. b. Your fingers will point in the opposite direction of the magnetic flux lines. c. Your fingers will point at right angles to the magnetic flux lines. d. Your fingers will point at a 45-degree angle to the magnetic flux lines. 7. The left-hand rule is useful to determine a. The direction of current flow b. The length of the magnetic flux lines c. The strength of the magnetic field d. Flux density
8. When two parallel conductors carry electrical current in opposite directions, their magnetic fields will a. Force them apart b. Pull them together c. Cancel each other out d. Rotate around the conductors in the same direction 9. The motor principle of changing electrical energy into mechanical energy requires a. Two semiconductors carrying current in opposite directions b. Two semiconductors carrying current in the same direction c. Two conductors carrying current in opposite directions d. Two conductors carrying current in the same direction 10. Which of the following will not increase induced voltage? a. Increasing the strength of the magnetic field b. Increasing the number of conductors cutting flux lines c. Increasing the speed of the relative motion between the conductor and the flux lines d. Increasing the angle between the flux lines and the conductor beyond 90 degrees 11. The _________ in an automobile DC generator rectifies AC to DC. a. Armature b. Commutator c. Field coil d. Loop conductor 12. In an ignition coil, low-voltage primary current induces a very high secondary voltage because of a. The different number of wire turns in the two windings. b. An equal number of turns in the two windings c. The constant current flow through the primary winding d. The bigger wire in the secondary winding 13. To reduce EMI, manufacturers have done all of the following except: a. Using low resistance in electrical systems b. Installing metal shielding in components c. Increasing the use of ground straps d. Using capacitors and choke coils
