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Test 2 Flashcards

1
Q

Type of induction from one wire to another (primary & secondary)

A

Mutual Induction

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2
Q

Opposing current induced in the coil of wire itself (autotransformer) A.T.

A

Self Induction

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3
Q

What kind of transformer from cathode to anode and why?

A

Step Up Transformer

Because you need more voltage than the power company can supply to propel electrons to anode for kVp

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4
Q

What kind of transformer to produce thermionic emission and why

A

Step down transformer

To produce more Amperage (current-mAs)

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5
Q

What kind of transformer to supply the cathode and why

A

Step down transformer need more amperage

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6
Q

What is Lenz’s Law

A

The induced current flow will be in the opposite direction (opposing) as the action that produces it (moving magnetic field.

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7
Q

How much current is induced to flow in the conductor placed in a changing magnetic field depends on…

  • strength
  • quickly oscillating (changing)
  • angle between conductor & field
  • # of turns on conductor
A

Farady’s Law

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8
Q

What kind of transformer do you need between the cathode and the anode? Why?

A

Step up transformer

need more kV (volts)

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9
Q

Voltage goes down amperage goes up

kind of transformer

A

Step down transformer

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10
Q

500 primary newtons to 300 secondary newtons

A

Step down transformer

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11
Q

When current flow changes direction

A

Magnetic field flips

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12
Q
  • Battery magnetic field only flows one way.
  • No changing magnetic field
  • Transformers will not work with this kind of electricity
A

Direct Electricity

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13
Q

Gets it’s power from an outlet-power source

A

Primary wire

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14
Q

Gets it’s power off a primary magnetic field

A

Secondary Wire

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15
Q
  • A primary A/C current (pluggin) next to but not touching….
  • A secondary A/C wire (not plugged in)
A

Transformer

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16
Q

A/C stand for

A

Alternating current

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17
Q
  • Charge flips

- Electrons flowing through a conductor

A

Magnetic field

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18
Q

Charge changes direction

A

Current flow

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19
Q

Electrons flowing through a conductor gives you….

A

Magnetic field

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20
Q

Bending the conductor concentrates charges in the …..of a conductor

A

Center

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21
Q

A coiled conductor is called a….

A

Solenoid

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22
Q

Inhibit the flow of electrons

rubber/plastic

A

Insulators

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23
Q

Allow electrons to flow

-ease of heat conduction typically equates to ease of electricity conduction

A

Conductors

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24
Q

Moving charges are concentrated on the surface of a …..(metal wire)

A

Conductor

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25
Q

Moving charges (electrons) are distributed throughout a…..(block of wood)

A

Non conductor

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26
Q
  • Study of stationary electrical charges
  • Moving on a conductor
  • Measured in Coulombs
A

Electrostatics

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27
Q

Attraction/Repulsion inversely proportional to distance between charges and directly proportional to strength of charges.
(same as binding energy)

A

Coulombs Law

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28
Q

Unlike charges do what

A

Attract

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29
Q

Like charges do what

A

Repulse

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30
Q

Relate Energy and Frequency

A

-Energy and Frequency are DIRECTLY proportional.
-Planks constant of proportionality:
h= 4.15x10(-15) eVs

   h= Planks constant
   e= hf Both of the above = c/a=freq.
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31
Q

What is the “source” in fluro?

A

Patient body

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32
Q

What is a typical source size?

“think anode target”

A

.3 mm

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33
Q

What is the “source” in diagnostic imaging?

A

The Anode/target spot

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34
Q

What is a realistic distance at which inverse square law is applicable?

A

7 x’s the source size away

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35
Q

The closer you are to the tube the more or less exposure you get?

A

More

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36
Q

If I double my distance from point “A” to point “B” from the x-ray tube what law would I use to calculate my new exposure rate?

A

Inverse square law

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37
Q

What is the formula for the inverse square law?

A

Old Intensity/New Intensity = New Distance squared/Old Distance squared

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38
Q

This applies to a point source…

A

Inverse square law

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39
Q

Some absorption
Some scatter
Some non-interaction

A

Shades of Gray

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40
Q

Items x-rays pass through virtually unimpeded. Appear black on image.

A

Radiolucent

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41
Q

Absorbs lots of x-ray photons looks white on image

A

Radiopaque

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42
Q

2 types of contrast

A

Radiopaque and Radiolucent

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43
Q

Beam that comes out of patient

A

Remnant Beam

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44
Q

Beam that hasn’t gotten to the patient coming from the tube

A

Primary Beam

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45
Q

Frequency is measured in…

A

Hertz

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46
Q

Weight and force are measured in…

A

Newtons

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47
Q

Resistance is measured in…

A

Ohms

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48
Q

Electricity is measured in…

A

Volts

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49
Q

Current is measured in…

50
Q

The less energy the (blank) photon retains, the greater the change in direction of travel.
(i.e. 90 degrees from patient)

A

Scatter-Compton interactions

51
Q

Happens IN the patient.

Photons give up some of their energy to matter and exit in a new direction with reduced energy.

A

Scatter-Compton interactions

52
Q

X-ray photons that are COMPLETELY absorbed.

more likely when incident photon is of relatively LOW energy to start with

A

Photo Electric Interactions

53
Q

X-ray and gamma-rays described by…

54
Q

RF Waves described by…

55
Q

Visible light described by…

A

Wavelength

56
Q

What is Electromagnetic Spectrum

A
  • Covers many orders of magnitude in wavelength.
  • Only x and gamma photons have sufficient energy to ionize
  • Compare for MRI:
    • much longer wavelengths
    • lower frequencies
    • lower energies
57
Q

Frequency x’s wavelength
FW
equal to speed of light

58
Q

How many cycles per sec.
Measured in hertz
Velocity/Wavelength

59
Q
  • The distance from any point on the wave to the same point on the next wave
  • Measured in meters
  • Velocity/frequency
A

Wavelength

60
Q

“C”
Frequency x’s Wavelength
Equal to velocity

A

Speed of light

61
Q

Lower kVp has (blank) wave lengths

62
Q

Higher kVp has (blank) wave lengths

63
Q

Speed of light (C)
3 x’s 10 (8) m/s
3 x’s 10 (10) cm/s
both above are the same thing

A

Electromagnetic Radiation

64
Q

Explain electromagnetic radiation

A

X and gamma rays travel at the speed of light or not at all…velocity of these photons is constant.
Sine waves represent the travel of these photons with consideration of electric and magnetic fields.

65
Q

The higher the kVp the (blank) absorption

 - ie more scatter
 - long scale
66
Q

The Lower the kVp the (blank) absorption

 - ie less scatter
 - short scale
 - higher patient exposure
67
Q

Photoelectric (PE)

Short scale contrast

A

Absorption

68
Q

Absorption is directly or indirectly related to patient exposure

69
Q

If you have electrons flowing through a conductor you have what

A

A magnetic field

70
Q

A change in voltage is based on the change or number of turns between what

A

The primary and secondary wire

71
Q

If current flow changes direction…

A

The magnetic field flips

72
Q

As voltage goes down, Amperage goes

73
Q

<p>

| A coiled conductor is called a...</p>

A

<p>

| Solenoid</p>

74
Q

The greatest concentration of electrons is on the (blank) of the wire.

A

Greatest curvature

75
Q

Step Up transformer =

A

Voltage UP

76
Q

Step Down transformer=

A

Voltage DOWN

77
Q

If one element goes out on THIS kind of circuit, ALL the elements go out

78
Q

If one element goes out on THIS kind of circuit, only THAT element goes out. The current flow has not been disrupted.

79
Q

In a Parallel circuit WHAT is constant

80
Q

In a Series circuit WHAT is constant

81
Q

Average US everyday appliances run on how much voltage?

82
Q

To get from an Alternating electrical Current (A/C) you have to do WHAT to get a full current

A

Rectification

83
Q

The number of positive peaks (impulses) per second in the US (60 Hz) for a
Single Phase, Half Wave rectified

A

1/120th Hz

84
Q

The number of positive peaks (impulses) per second in the US (60 Hz) for a
Single phase, Full Wave rectified

85
Q

The number or positive peaks (impulses) per second in the US (60 Hz) for a
Triple Phase, Full Wave rectified

A

High Frequency Voltage

86
Q

What kind of flow comes from the power company?

87
Q

What is the advantage of using a Single phase 1/2 wave: suppressing the negative 1/2 cycle, effect have on the Tube?

A

Reduces the amount of heat, causing less damage to the tube

Still only getting x-rays half of the time

88
Q

What does a Single phase, Full wave: inverting the negative 1/2 cycle, effect have on the tube/x-rays?

A

The Cathode is heated the whole time (pulsating direct current)

89
Q

A 3 phase, 6 pulse or 3 phase, 12 pulse rectified current produces what?

A

Near direct current (eliminating the variations in efficiency)

90
Q

What is takes to push electrons through is measured in….

91
Q

The formula for power is…

A

P=IV

V=IR or P=I(IR) or P=(Isquared)(R

92
Q

You can calculate power by knowing any of the following two:

A

Voltage, Amperage, Resistance

93
Q

Stored (source of) electric energy

and where might we as x-ray techs use this

A

Battery

-Portable machine

94
Q

Supplied with current to Produce Mechanical energy (motion) and where might we as x-ray techs use this

A

Motor

-Physical activity

95
Q

Mechanical energy (motion) Produces Electrical Energy (amperage) and example of what is a generator

A

Generator

-Hamster in a wheel

96
Q

A coiled conductor (wire)

97
Q

A coiled conductor with iron core

which intensifies the magnetic fields

A

Electromagnet

98
Q

Current is induces to flow in a conductor that is in a moving (changing) magnetic field (so alternating current is a prerequisite)

99
Q

Faraday’s Law says…

A

How much current is induced to flow in a conductor placed in a changing magnetic field depends on…

  • How STRONG the magnetic field is
  • How QUICKLY the magnetic field is oscillating (changing)
  • What the angle between the conductor and the field is
  • How MANY TURNS are on the conductor (ie 300 or 200, etc)
100
Q

Lens’s Law says…

A

The induced current flow will be in the opposite direction (“opposing”) as the action that produces it (moving magnetic fields)

101
Q

Self Induction is induced by using a/an what kind of transformer

A

Autotransformer

102
Q

Mutual induction is induced by using a/an what kind of transformer

A

Primary & Secondary

103
Q

Rectification (conversion from AC to near DC) must come before or after all transformers in the x-ray tube?

104
Q

How many transformers are in the x-ray tube before rectification occurs?

105
Q

Change in (blank) from primary to secondary wire will be (blank) proportional to the ratio of coils/turns.

A

Voltage

Directly

106
Q

Change in (blank) from primary to secondary is (blank) proportional to ratio of coils

A

Amperage

Inversely

107
Q

50,000 turns secondary; 1000 turns primary

  • What kind of transformer is it?
  • Will voltage go up or down? How much?
  • Will Amperage go up or down? How much?
A
  • Step up
  • Voltage up 50 x’s
  • Amperage down by 1/50th
108
Q

400 turns secondary 16,000 turns primary

  • What kind of transformer is it?
  • Will voltage go up or down? How much?
  • Will amperage go up or down? How much?
A
  • Step down
  • Voltage goes down 1/40th
  • Amperage goes up 40 x’s
109
Q

Describe and Autotransformer

A

Has only one wire with variable taps and is a self-inducing transformer

110
Q

Where does voltage (kVp) selection occur?

A

Autotransformer

111
Q

Induction motor does what

A

Makes the Anode spin inside a vacuum

112
Q

A high voltage Step Up transformer gets us from 220 V coming in from the wall to…

A

70-110 KILOvolts for x-ray imaging

113
Q

What measures power coming in and makes adjustments to keep it consistent before it gets to the Autotransformer

A

Line voltage Compensation Autotransformer

114
Q

What are the 3 formulas for the speed of light

A
  • 3x10 (8)
  • 3x10 (10cm)
  • 186,000 miles per second
115
Q

Velocity of gamma and x-rays is…

116
Q

Cycles per second is also

117
Q

Frequency and wavelength are (blank) related

118
Q

Exposure rate, intensity, MR all indicate…

A

Inverse square law

119
Q

Energy of a photon…

A

Planks constant

e=hf

120
Q

Columbs Law

A

As distance between charges increases, the force decreases

magnets

121
Q

Turns ratio

A

number of turns secondary/ over number of turns primary

Physics (7 decks)

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