Ch 20

1. AC can be _______ to DC
5. _______ inductance is the ability of one circuit to induce an emf in a nearby circuit in the presence of a changing circuit
7. the _____ at which the coil in an AC generator rotates determines the maximum generated emf
9. conducting rings at the end of a conducting loop are called ____ rings
12. stationary graphite strips connected to the external circuit
13. a motor can perform mechanical work when a shaft connected to its rotating coil is attached to an external device
14. ____ current is the value of AC that gives the same heating effect that the corresponding value of the DC
15. a device that converts mechanical energy into electrical energy
17. ______ current and emf are measured in AC circuits
18. a resistor ____ changes in motion whether they move in one continuous direction or shift direction periodically
19. the frequency of rotation in the US and Canada for commercial generators is ___ Hz
20. a generator uses the rotary motion of a turbine to turn a wire _____ in a magnetic field
22. an emf that acts to reduce current in a motor coil is called ______ emf
23. the coil connected to a switch and a battery instead of a magnet to produce a magnetic field is called the _____ coil

2. the conducting loop in an AC generator must be free to ______ through the magnetic field
3. a current is supplied to the loop in a motor by an ________ source
4. a generator produces a _________ changing emf
6. a device that increases or decreases the emf of AC
8. in a DC generator a single split slip ring that contacts the rotating loop
10. a motor is nearly _______ to a DC generator in construction
11. AC changes direction at a constant _____
14. in most commercial power plants mechanical energy is provided in the form of rotational motion
16. ______ can be used in either AC or DC applications
21. the basic principle of electromagnetic induction was first demonstrated by ___________
24. machine that converts electrical energy to mechanical energy