Date Class Name Chapter Test A continued 7. Which conversion process is the basic function of the electric motor? a. mechanical energy to electrical energy b. electrical energy to mechanical energy c. low voltage to high voltage, or vice versa d. alternating current to direct current 8. In a two-coil system, the mutual inductance depends on a. only the geometrical properties of the coils. b. only the orientation of the coils to each other. c. both the geometrical properties of the coils and their orientation to each other. d. neither the geometrical properties of the coils nor their orientation to cach other. 9. In a primary-secondary coil combination, which of the following conditions is met in the primary coil when the current in the secondary coil is at its maximum? a. The current is maximum in a positive direction. b. The current is maximum in a negative direction. c. The rate of current change is maximum. d. The voltage is maximum in a positive direction. 10. What is rms (root-mean-square) current? a. the value of alternating current that gives the same heating effect that the corresponding value of direct current does b. an important measure of the current in an ac circuit c. the amount of direct current that would dissipate the same energy in a resistor as is dissipated by the instantaneous alternating current over a complete cycle d. all of the above 1 1. A generator's maximum output is 220 V. Calculate the rms potential difference. a. 1 10 V c. 160 V b. 150 V d. 310 V 12. The rms current in an ac current is 3.6 A. Find the maximum current. a. 5.1 A C. 2.8 A b. 4.7 A d. 1.8 A 13. A step-up transformer used on a 120 V line has 95 turns on the primary and 2850 turns on the secondary. What is the potential difference across the secondary? a. 30 V c. 2400 V b. 1800 V d. 3600 VName Class Chapter Test A continued 14. A potential difference of 115 V across the primary of a step-down transformer provides a potential difference of 2.3 V across the secondary, What is the ratio of the number of turns of wire on the primary to the number of turns on the secondary? a. 1:50 c. 25:1 b. 50:1 d. 1:25 SHORT ANSWER 19. List three ways to induce a current in a circuit loop, using only a magnet. 20. What is a turbine's rotational motion used for in commercial power plants?Assessment Electromagnetic Induction MULTIPLE CHOICE In the space provided, write the let.s , of the term or phrase that best completes each statement or best answers each question. 1. A current can be induced in a closed circuit without the use of a battery or an electrical power supply by moving the circuit through a a. high temperature field. c. magnetic field. b. gravitational field. d. nuclear field. 2. A loop of wire is held in a vertical position at the equator with the face of the loop facing in the east-west direction. What change will induce the greatest current in the loop? a. raising the loop to a higher elevation b. moving the loop north c. rotating the loop so its face is vertical d. rotating the loop so its face is north-south 3. Electricity may be generated by rotating a loop of wire between the poles of a magnet. The induced current is greatest when a. the plane of the loop is parallel to the magnetic field. b. the plane of the loop is perpendicular to the magnetic field. c. the magnetic flux through the loop is a minimum. d. the plane of the loop makes an angle of 45 with the magnetic field. 4. According to Lenz's law, the magnetic field of an induced current in a conductor will a. enhance the applied field. b. heat the conductor. c. increase the potential difference. d. oppose a change in the applied magnetic field. 5. According to Lenz's law, if the applied magnetic field changes, a. the induced field attempts to keep the total field strength constant. b. the induced field attempts to increase the total field strength. c. the induced field attempts to decrease the total field strength. d. the induced field attempts to oscillate about an equilibrium value. 6. Which of the follswing options can be used to generate electricity? a. Move the circuit loop into and out of a magnetic field. b. Change the magnetic field strength around the circuit loop. c. Change the orientation of the circuit loop with respect to the magnetic field. d. all of the aboveClass Date Chapter Test A continued 21. The rms emf across a resistor is equal to what? 22. Explain how the terms energy. electromagnetic force, electromagnetic wave, and electromagnetic radiation are related to one another. PROBLEM 23. A coil with 275 turns and a cross-sectional area of 0.750 m experiences a magnetic field whose strength increases by +0.900 T in 1.25 s. The plane of the coil moves perpendicularly to the plane of the magnetic field. What is the induced emf in the coil? 24. An ac generator has a maximum output emf of 4.20 x 10' V. What is the rms potential difference? 25. A step-up transformer used on a 120 V line has 38 turns on the primary and 5163 turns on the secondary. What is the potential difference across the secondary