Review Questions Flashcards by Lexi Zanolini

Digital fluoroscopy eliminates which of the following?
1. The need for a radiographer
2. Postprocedure “overhead” image
3. Image acquisition
4. Accurate positioning

Postprocedure “overhead” images

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What is the smallest particle of an element that retains characterstics of the element?

Atom

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In digital fluoroscopy, the image must be turned into digital form by what device?

Analog-to-digital converter

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X-ray travels as bundles of energy called?

Photons

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What is the atomic mass?
1. The number of photons + neutrons
2. The number of photons
3. The number of electrons
4. The number of photons + electrons

The number of photons plus the number of neutron

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What device may be used to ensure consistancy of radiographic quality from one expoure to the next?

Automatic exposure control (AEC)

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When a predetermined level of ionization is reached in the ionization chamber, what does the machine do?

The exposure is terminated

Exposure time is very dependent upon kVp

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What type of x-ray machine uses a continually decreasing mA for the shortest times possible?

Falling load generator

Uses the max heat storage capacity at every mA & time combo

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What type of current is required for proper operation of the x-ray tube?
1. Direct
2. Falling load
3. Alternating
4. Fluctuating

Direct

This necessitates the using of a rectiier to change AC to DC

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The law stating that the outer shell of an atom can contain no more than eight electrons is called?

Octet rule

It does not stipulate that there MUST be 8 electrons in the outer shell

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Examples of particulate radiations are:
1. X-ray, gamma rays, and cosmic rays
2. Helium nuclei and beta particles
3. Electrons, protons, and meteorites
4. X-ray and quarks

Helium nucleai and beta particles

Particulate radiations are highly ionizing

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Electromagnetic radiation travels…

In waves as a straight path

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Electromagnetic radiation travels in bundles of energy called?

Photons

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At what speed do x-rays travel at?

The speed of light - 186,000 miles per second

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Waves of radiation are called?

Sine waves

Wavelength and frequency are inverse to one another

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Wavelength is defined as the distance from __ to __.

Peak to peak

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Frequency is defined as?

The number of waves passing a point per unit time

Higher frequency = shorter wavelengths; lower freq. = longer wavelengths

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The speed of x-ray is based on?
1. mAs
2. kVp
3. Size of patient
4. The fact that they are a form of electromagnetic radiation

The fact that they are a form of electromagnetic radiation

All x-rays travel the same; The speed of light

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Wavelength and frequency are what to eachother?

Inversely proportional to eachother

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The x-ray beam changes as it travels through the patient by process of?

Attenuation

The x-rays may be absorbed or scattered

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Name the Law: The intensity of radiation is inversley proportional to the square of the distance between the source of radiation and the person receiving it

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Inverse Square Law

Ex: Rad is 10 R at 3 feet so at 6 feet its 2.5 R. It is 1/4 not half!

As radiation strike matter:
1. The energy of the ray is destroyed
2. The energy of the ray is increased as they aquire the energy of atoms
3. The energy is transferred to the atoms according to the law of conservation of energy
4. The energy is converted to matter according to Enstein’s theory

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The energy is transferred to the atoms according to the law of conservation of energy.

Energy can not be created or destroyed, only changed

Which statements are true?
1. Electrostatics is the sudy of electric charges at rest
2. The movement of electrons from one object to another is called ionization
3. Like charges attract, and unlike charges repel
4. Electrostatic charges concentrate on a conductor in the are of greatest curvatue
5. Friction, contact, and induction are methods of ionization

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1 and 4 are correct.
* 1. Electrostatics is the sudy of electric charges at rest
* 4. Electrostatic charges concentrate on a conductor in the are of greatest curvatue

Which statement is False?
1. A magnetic field always surrounds an electrical charge in motion
2. Current flows back and forth in AC
3. Current flows in one direction in DC
4. The volt is the unit of electrical current
5. A conductor allows the free flow of electron
6. The ampere is the unit of electromotive force
7. The volt is the unit of potential difference
8. The path of electrical current is called the circuit
9. Ohm’s law is calculated using the equation V1=R
10. A semiconductor is a material that may act as a conductor under some conditions and as an insulator under other conditions

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4, 6, & 9 are false.
* 4. The volt is the unit of electrical current
* 6. The ampere is the unit of electromotive force
* 9. Ohm’s law is calculated using the equation V1=R

Electromagnetic induction is the process of causing the electrical current to flow in a conductor: 1. When it is placed in contact with another conductor 2. When it is placed in contact with an insulator 3. When it is placed in contact with a superconductor 4. When it is placed in the magnetic field of another conductor

When it is placed in the magnetic field of another conductor

The two types of electromagnetic inductions are?

Self induction (occurs at an autotranformer) and mutural induction (occurs in step-up and step-down transformer)

Self-induction is used in the operation of what device?

Autotransformer

The strength of the magnetic fields in a tranformer is increased by? 1. Coiling the wires and placing them in adjoining machines 2. Coiling the wires and letting their magnetic fields overlap 3. Keeping the wires very straight 4. Replacing the wires with diodes

Coiling the wires and letting their magnetic fields overlap | This intensifies the magnetic fields, making them more efficent

Electricity is supplied to the imaging deprtment by? 1. Motor 2. Rectifier 3. Generator 4. Voltmeter

Generator

The electricity provided to the radiology department is? 1. 110 Hz or 220 Hz DC 2. 110 Hz or 220 Hz AC 3. 60 Hz AC 4. 60 Hz DC

60 Hz AC | 60 Hertz means 60 cycles per second. the voltage may be 110 or 220

The electricity provided to the radiology department operates at? 1. 120 pulses per second 2. 60 pulses per second 3. 110 pulses per second 4. 220 pulses per second

120 pulses per cycle | 60 cycles per second results in 120 pulses per second

High-frequency power: 1. Is less effective than single phase power 2. Has almost no ripple 3. Has more ripple than three-phase power 4. Is yet unproved

Has almost no ripple | low ripple = higher avg photon energy. High frequency = more efficient

The primary advantage of three-phase poweris that: 1. Voltage drops to zero only 6 times per second 2. Voltage drops to zero only 12 times per second 3. Voltage never drops to zero 4. Voltage is always at peak value

Voltage never drops to zero

A variable transformer that is used to select kVp for the x-ray circuit is the: 1. Step up tranformer 2. Autotransformer 3. Step down transformer 4. Filament transformer

Autotranformer | Autotransformer is variable transformer that operates on self-induction

A transformer that has more turns in the secondary coil than in the primary coil is called a: 1. Step- up transformer 2. Solenoid 3. Step-down transformer 4. Filament

Step-up Transformer

What is the transformer used to boost voltage to kilovoltage levels called? 1. Autotransformer 2. Step-down transformer 3. Step-up transformer 4. Low-voltage transformer

Step-up transformer

Voltage coming to the x-ray machine is kept constant through the use of a(n): 1. Autotransformer 2. Step-down transformer 3. Rectifier 4. Line voltage compensator

Line voltage compensator

A stepdown transformer: 1. Steps down voltage 2. Steps down current 3. Steps up voltage 4. Steps up resistance

Steps down voltage

Where does thermionic emission occur? 1. Step-down transformer 2. Rectifier 3. Cathode 4. Timer

Cathode | Thermionic emission is the boiling of electrons from the filament wire

Which of the following devices is prereading? 1. Step-down transformer 2. Rectifier 3. Timer 4. kVp meter

kVp meter

Which device reduces voltage and provides current to produce an electron cloud or space charge at the filament? 1. Step-down transformer 2. Rectifier 3. Cathode 4. Timer

Step down transformer | The step-down transformer is located in the filamnet circuit

Which device is electron, with increments of 0.001 second? 1. Step-down transformer 2. Rectifier 3. Cathode 4. Timer

Timer

What changes AC to DC? 1. Stepdown transformer 2. Rectifier 3. Cathode 4. Timer

Rectifier

Which of the following is surrounded by a negatively charged focusing cup? 1. Step-down transformer 2. Rectifier 3. Filament 4. Timer

Filament

Which of the following is composed of solid-state, silicon-based diodes? 1. Step-down transformer 2. Rectifier 3. Cathode 4. Timer

Rectifier | Rectifier changes AC to DC

What regulates the duration of x-ray production? 1. Step-down transformer 2. Rectifier 3. Cathode 4. Timer

Timer

What is located in the x-ray circuit between the high-voltage transformer and the x-ray tube? 1. Step-down transformer 2. Rectifier 3. Cathode 4. Timer

Rectifier | AC is changed to DC so it flows one direction in the x-ray tube

Which of the following measures tube current? 1. Anode 2. mA meter 3. Ionization chamber 4. Falling load generator

mA meter

What device spins at 3,300 to 10,000 rpm? 1. Anode 2. mA meter 3. Ionization chamber 4. Step-up Transformer

Anode

What device uses maximum heat storage ability of the tube to deliver mAs? 1. Anode 2. mA Meter 3. Ionization chamber 4. Falling load generators

Falling load generator

What is the source of bremsstrahlung and characteristic rays? 1. Anode 2. mA meter 3. Falling load generator 4. Stepup transformer

Anode

Review Questions Flashcards

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