Chaper 4-Electricity Flashcards Preview

Radiography > Chaper 4-Electricity > Flashcards

Flashcards in Chaper 4-Electricity Deck (64)
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31

AKA Electric potential. Higher voltage-higher potential.

EM

32

Flow of electrons

Electric current

33

Matter through which electrons flow easily

Conductors

34

Matter that inhibits flow of electrons

Insulators

35

Most ____ are good conductors

Metals
Ex silver, gold, copper

36

Glass, clay, rubber, plastic are all examples of _______

Insulators

37

Under some conditions behaves as an insulator and sometimes as a conductor

Semiconductors

38

property of limited resistance to electron flow below a critical temperature.

Superconductivity

39

Electrons flow on the ____ surface of a wire

Outer

40

When resistance is controlled and electrons flow over a crossed path

Electric Circuit

41

Length is _____ proportional to resistance

Directly

42

Measures number of electrons flowing in electric circuit

Ampere/amp (A)

43

Measures electric potential

Volts

44

Unit of electrical resistance

Ohms

45

Ohm's law ______

V=IR

46

All circuit elements are connected in a line along same conductor

Series

47

__1__ of voltage across each circuit element=__2__ circuit voltage

1. Sum
2. Total

48

Has elements that bridge conductors rather than lie in a line along a conductor

Parallel Circuit

49

__1__ of all CURRENTS through each circuit element=total __2__ current

1. Sum
2. Circuit

50

Does voltage change in a parallel circuit?

NEVER

51

_____ NEVER changes in a SERIES circuit

Amperage

52

DC=electrons flowing in _____ direction(s) along a conductor

One

53

AC=current in which electrons ______ back an forth

Oscillate

54

Horizontal or X-axis of waveform represents __1__. Vertical or y-axis represents __2__ of current

1. Time
2. Amplitude

55

For DC, electrons always flow in the same __1__ with same velocity, so DC is represented by a __2__ line.

1. Direction
2. Horizontal

56

_____ separation between line and time axis represents magnitude of current

VERTICAL

57

Are series elements interdependent or independent

Interdependent

58

Parallel elements are _____

Independent

59

Waveform for AC is _____

Sine curve

60

Electrons flow first in __1__ direction and then in __2__ direction

1. Positive
2. Negative