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| Question | Answer |
|---|---|
| Nonmetals make the best conductors. | False |
| Which of the following is a common insulator? | plastic |
| An open circuit will conduct electricity. | false |
| What purpose does a circuit breaker serve in an electric circuit? | Protect against circuit overload |
| An electrical device with a deficiency of electrons will do which of the following when grounded? | Take on electrons until neutral |
| Which of the following symbols momentarily stores electric charge? | ---] [--- |
| What charge will an atom with more protons than electrons have? | positive |
| The movement of which of the following is most often recognized as electricity? | Electrons |
| Which of the following will move in solid conductors? | negative charges |
| According to Coulomb’s Law, what will happen to the electrostatic force between two charges if the distance between them is cut in half? | Quadruples |
| When electrons are rubbed off one object and deposited to another, this is electrification by: | Friction |
| What happens to the electric potential as the electric field increases? | Increase |
| Which of the following are required for electric current to exist? 1. Electric potential difference. 2. Equal number of positive and negative charges. 3. Suitable medium in which to travel. | 1 &3 |
| The SI unit for charge or current flow per second is: | Ampere |
| If a given conductor is carrying a high voltage, what is the amperage? | Low |
| In which media will ions drift towards the oppositely charged electrode? 1. Vacuum 2. Gas 3. Ionic solution 4. Metallic conductor | 2 and 3 only |
| The property of a conductor that hinders the flow of electricity is: | Resistance |
| Which of the following will have the greatest resistance? | Material with few free electrons/ high temperature. |
| An electric circuit has a current of 6 amperes and a resistance of 3 ohms. What is the current if you increase the total resistance in the circuit to 6 ohms? (Assume that the voltage is unchanged.) | 3 ampere |
| A meter placed in the heating resistor circuit shows that 5A is flowing through the resistor. If the resistor is 20 Ω, what is the voltage across it? | 100V |
| A 110 V heater requires 15 A. What is the power consumption? | 1650W |
| An x-ray imaging system has a 30 kW generator. If the maximum tube voltage is 150 kV, what is the available tube current? | 200mA |
| How many volts are required to move a current of 60 amperes across a circuit having a resistance of 2 ohms? | 120 volts |
| A series circuit has resistors measuring 10, 15, 20 and 30 ohms with a current of 5 amps. What is the total voltage of the circuit? | 375volts |
| Three resistors are connected in parallel to a battery of 18V, with resistances of 3 ohms, 6 ohms, and 9 ohms. What is the total resistance? | 1.6ohms |
| What is the total current in the circuit connected in parallel to a battery of 18V, with resistances of 3 ohms, 6 ohms, and 9 ohms? | 11 amps |
| Four resistors are connected in series to a battery of 6 V, with resistances of 2 ohms, 4 ohms, 5 ohms, and 10 ohms. What is the total resistance? | 21 ohms |
| What is the total current in the series circuit with a battery of 6 V, with resistances of 2 ohms, 4 ohms, 5 ohms, and 7 ohms? | .33 amps |
| The rotation of electrons on their axis is the property called ____________. | electron spin |
| An electric potential applied to a conductor produces __________. | Electric current & Magnetic field |
| Like charges _______ and unlike charges _______. | attract, repel |
| An alternating (AC) current is represented by a __________ line. | sinusoidal |
| The charges on an electrified object are distributed __________. | evenly throughout the object |
| In the United States, alternating current goes through a complete cycle every _____ second. | 1/60 |
| Electrification occurs through the movement of ___________. | electrons only |
| What is the unit of electric potential? | volt |
| A ___________ uses direct current. | flashlight |
| Alternating current is produced by a ___________. | generator |
| The smallest unit of electrical charge is the __________. | electron |
| A _________ is a source of direct current. | battery |
| A charged particle in motion creates a(n) ______________. | magnetic field |
| On the surface of an electrified object, the charges concentrate on the __________. | sharpest curvatures |
| Electrostatic force is _________ proportional to the distance between charges, and _______ proportional to the product of the charges. | inversely, directly |
| Electrical power is measured in _____. | watts |
| What is the unique electron characteristic of magnetic materials? | They all orbit in predominantly one direction. |
| Lines of magnetic flux traveling in the same direction will attract each other. | Fasle |
| At what distance would you expect two magnets to have the strongest reaction to each other? | 1/8 inch |
| An iron bar wrapped with a wire carrying electric current is what class of magnet? | Electromagnet |
| Platinum is magnetically classified as which of the following? | Paramagnetic |
| Rubbing a ferromagnetic material against a permanent magnet will magnetize that material. | True |
| Like poles of a magnet or charges of electric fields will: | repel |
| Which scientist used a compass and a wire carrying electric current to demonstrate and study electromagnetism? | Oersted |
| If this circle with a dot in the center represents a wire carrying electric current to toward you, which of the following is true? | Magnetic flux lines flow counterclockwise |
| Depending on the application of the right-hand rule, the thumb can indicate either current flow or direction of the magnetic field. | True |
| The following describes four different coils. Which one, if moved through a magnetic field, would create the least voltage? | 10 turns |
| If the number of coils of a conductor is 40 and the voltage is 110, what will the voltage be if the number of coils is increased to 80? | 220 |
| The north and south ends of an electromagnet change each time an AC changes direction. | true |
| Which scientist formulated a law that explains a principle of electromagnetic induction? | Lenz |
| The ability of a material to attract iron, cobalt, or nickel is called | magnetism |
| The lines of force in space associated with a magnet are called | lines of flux |
| Inside the magnet, the lines of flux travel from | South Pole to North Pole |
| Outside the magnet, the lines of flux travel from | North Pole to South Pole |
| Like poles of a magnet _________ each other and opposite poles ________ each other. | repel; attract |
| The force of magnetic attraction varies | inversely with the square of the distance between the poles. |
| Magnetic field strength is measured in | Tesla |
| A material that is weakly repelled by a magnetic field is classified as | diamagnetic |
| A material that is strongly attracted to a magnetic field is | ferromagnetic |
| A material that is weakly attracted to a magnetic field is | paramagnetic |
| Wood and plastic are considered: | nonmagnetic |
| The idea that electricity flowing through a conductor produces a magnetic field was identified by | oersted |
| The idea that electricity could be induced in a wire by moving it through a magnetic field was discovered by | faraday |
| According to Faraday’s Law of Electromagnet Induction, if the strength of the magnetic field is increased, _________is also increased. | current |
| An electromagnet includes: | a coil of wire, an iron core, a solenoid. |
| Reducing the number of coils in the wire will result in | reduced electromagnetic induction. |
| Increasing the strength of the magnetic field results in | increased electromagnetic induction. |
| Slowing down the speed at which the conductor passes through the magnetic field results in | reduced electromagnetic induction. |
| Mutual induction involves electricity being induced into a ______________. | secondary coil |
| With mutual induction, to induce voltage in the secondary coil, there must be | alternating current in the primary coil of wire. |
| _______________ current is induced in the secondary coil when mutual induction takes place. | alternating |
| With self-induction, the secondary current | is in the original coil and opposes the original current. |
| Self-induction is based on the concepts introduced in | Lenz’s law. |
| Lines of flux in the same direction attract each other. | false |
| Lines of flux in the opposite directions attract each other. | true |
| Nonmagnetic material, when interacting with a magnet, distorts the magnetic field. | false |
| Every magnet has a north, south, east, and west pole. | false |
| With alternating current, the north and south poles of the magnetic field surrounding the wire change each time the electrons change direction. | true |
| What atomic characteristic of a magnetic material creates a dipole? | their electrons spin in predominantely one direction |
| What aligns to form magnetic domains? | atoms |
| If a magnetic material is placed in the field of a magnet, what happens to that field? | it is distorted |
| A magnet is formed when all of its “atomic magnets” align. | true |
| According to the laws of magnetism, how many poles will an atomic magnet have? | two poles at this level |
| The south poles of two magnets are placed 1 millimeter from each other. Which of the following describes the reaction? | very strong repulsion |
| An iron bar exposed to a strong magnetic field may become which of the following? | artificial permanent |
| Materials strongly attracted to magnets are classified as which of the following? | ferromagnetic |
| Heating a magnetized iron bar will cause it to lose some or all of its magnetism. | true |
| Tapping an iron bar against a solid object in a magnetic field will help magnetize that material. | true |
| Magnetic poles can exist separately from each other and may have only one pole. | false |
| With electric fields, positive and negative charges exist separately. | true |
| The inverse square law applies to both electric and magnetic fields. | true |
| Which scientist conducted experiments demonstrating that a magnetic field created by a flow of electric current was greater than the earth’s magnetic field? | oersted |
| If this circle with an “x” in the center represents a wire carrying current away from you, which of the following is true? | magnetic flux lines flow clockwise |
| What is the advantage of configuring a wire carrying electric current into a coil (spring)? | strengthens the magnetic field |
| The following are four different magnetic fields. If the same coil of wire is passed through each, which will result in the greatest induced voltage? | 2.5T |
| Which of the following conductor angles, in relation to the magnetic field, will produce the greatest voltage? | 90 degree angle to the field |
| The basic premise of electromagnetic induction is that which of the following move? | 1 &2 only, (magnetic field) |
| Why is AC desirable for mutual induction? | it creates a moving magnetic field |
| What happens to filament electron after they interact with atoms? | 1 & 2:Fill a shell vacancy in an atom & Become part of the current through the tube. |
| Only L shell electrons can fill K shell vacancies. | False |
| If an N shell electron fills an M shell vacancy, what is the energy of the photon produced? | 2.22 |
| If an O shell electron fills an L vacancy, what is the energy of the photon produced? | 12.02 |
| If filling a K shell vacancy, which shell electron would produce the highest energy characteristic photon? | O shell |
| Characteristic photons are produced with the filling of each shell vacancy. | True |
| L characteristic originates from which of the following shells being filled? | L |
| As the distance between the filament electron and nucleus gets smaller, what happens to the brems photon energy? | Increase |
| If a filament electron enters an atom with 70 keV of energy, passes the nucleus and leaves with 10 keV, what is produced? | 60 kVp brems |
| Brems is the interaction that occurs most often. | True |
| During x-ray production the electrons penetrate the target approximately | .5 mm |
| X-rays are produced by | characteristic and bremsstrahlung interactions. |
| When filament electrons enter the anode target, they interact with | outer shell electrons of tungsten atoms |
| At the anode target, how much of the energy from filament electrons is lost as heat and how much will result in x-ray production. | 99% every lost as heat; 1% result in x-ray |
| When a filament electron knocks out a K shell electron from the tungsten atom, it leads to | a characteristic x-ray photon |
| Characteristic x-ray photons result | when an inner-shell electron is knocked out and when outer-shell electrons fill the vacancy in an inner shell. |
| The energy of the characteristic x-ray photon depends on | ALL THE ABOVE: the binding energy of the inner-shell electron, the energy level of the filament electron, the shell of the electron that is dropping into the vacancy. |
| A filament electron removes a K shell electron and an M shell electron fills the vacancy. The K shell binding energy is 69.5 keV and the M shell binding energy is 2.8 keV. What is the energy of the K-characteristic photon produced? | 66.7keV |
| The process of a series of outer-shell electrons filling inner-shell vacancies right after the other is called | characteristic cascade |
| Bremsstrahlung means | braking radiation |
| During the bremsstrahlung interaction, the filament electron | is attracted to the nucleus but not absorbed |
| The energy of the brems photon depends on | ALL THE ABOVE: the original energy of the filament electron, the strength of the attraction between the electron and the nucleus, the energy of the filament electron as it leaves the tungsten atom |
| If a filament electron enters the tungsten atom with 80 keV of energy and leaves the atom with 75 keV of energy: | the filament electron traveled very far from the nucleus |
| If a filament electron leaves the tungsten atom with 15 keV of energy and the brems photon produced was 65 keV, how much energy did the incoming filament electron have? | 80 keV |
| The average energy of a brems photon is ______ of the kVp selected at the control panel. | 1/3 |
| The majority of the x-ray photons produced are | brems photons |
| A discrete emission spectrum is a graphic representation of | characteristic radiation |
| A continuous emission spectrum is a graphic representation of | bremsstrahlung radiation |
| The x-ray emission spectrum is a graphic illustration of | characteristic radiation and bremsstrahlung |
| The x-axis for all emission spectra represents the | energy level of the photons |
| The y-axis for all emission spectra represents the | number of photons |
| The discrete emission spectrum typically displays | BOTH OF THESE: K-characteristic & L -characteristic |
| L-characteristic and higher photon energies are not usually displayed on a discrete emission spectrum because | the energies of the photons produced are too low for image formation. |
| With a 75-kVp exposure, the energy of the photons displayed on the continuous emission spectrum can range from just above 0 to | 75 keV |
| With a 75-kVp exposure, the peak of the curve on the continuous emission spectrum is approximately | 25 keV |
| With the x-ray emission spectrum, the discrete line is the highest energy ___________________ bar. | K-characteristic |
| For a tungsten target, the discrete line on the x-ray emission spectrum is approximately | 69 keV |
| Changes along the x-axis of the x-ray emission spectrum reflect changes in the _________________ of the x-ray beam. | quality |
| If all other factors remain constant, a decrease in the mA results in | a decrease along the y-axis |
| Increasing the kVp results in | an increase along the y-axis and a shift to the right along the x-axis |
| Adding filtration in the path of the beam results in the x-ray emission spectrum | BOTH OF THESE: Changing along the x-axis & changing along the y-axis |
| Changing from a high-frequency generator to a single-phase generator results in the x-ray emission spectrum | BOTH OF THESE: chaining along the x-axis & changing along the y-axis |
| Changing the ___________________ results in changes to the x-axis, y-axis, and location of the discrete line of the x-ray emission spectrum. | target material |
| As filament electrons enter the anode target, most interact with inner shell electrons of the tungsten atoms. F/T | False |
| At the anode target, 1% of the energy from filament electrons is lost as heat and 99% will result in x-ray production T/F | false |
| A 65-keV filament electron is not able to produce characteristic radiation. T/F | true |
| When 65 kVp is set on the operating console, no K-characteristic radiation is produced. T/F | True |
| T/F The stronger the attraction between the filament electron and the nucleus, the less energy the brems photon has. | False |
| T/F.The discrete emission spectrum is limited to a few specific values. | true |
| T/F. When the kVp is changed from 60 to 120, the discrete line on the x-ray emission spectrum shifts to the right. | False |
| Which of the following tissue types is likely to have the greatest number of photoelectric events? | Bone |
| Which interaction, within the diagnostic range, does not involve the removal of an orbital electron? | Classical |
| A photon of 10 MeV colliding with a nucleus will likely result in what type of interaction? | photodisintegration |
| Which kVp will produce the greatest number of photodisintegration events? | None of the above |
| Which interaction in the diagnostic range involves the total absorption of the incident photon? | photoelectric |
| The ejection of a nuclear fragment is part of which interaction? | Photodisintegration |
| When the kVp selected is equal to or slightly greater than the inner shell binding energy of a tissue atom, which interaction predominates? | photoelectric |
| Secondary photons are also produced during what type of interaction? | photoelectric |
| Which of the following is an undesirable contributor to image contrast and density? | Compton |
| During coherent scattering, the scattered photon possesses _____ as the incident photon. | The same energy, the same frequency, and the same wavelength. |
| T/ F: A filament (projectile) electron will undergo only one interaction. | F |
| What is the source of energy that results in characteristic photons? | The differences in shell energy levels of the electron filling the vacancy. |
| If an N shell electron fills a K shell vacancy, what is the energy of the photon produced? | 68.9 |
| If an O shell electron fills an M shell vacancy, what is the energy of the photon produced? | 2.74 |
| Given vacancies are filled randomly, which shell is most likely to fill an L shell vacancy? | M |
| If filling a K shell vacancy, which shell would produce the weakest photon? | L |
| Which shell interaction produces the most useful characteristic photon? | K |
| Which of the following filament electron energies will remove a K shell electron from a tungsten atom? | 70 |
| If a filament electron enters an atom with 100 keV, passes the nucleus and exits with no kinetic energy, what is produced? | 100 keV brems |
| What is the average energy of a beam produced at 90 kVp? | 30 keV |
| In the production of Bremsstrahlung radiation, the incident electron: | Is deflected with resulting energy loss |
| Characteristic x-rays are produced when: | |
| As electrons impinge on the target surface, more than 99% of their kinetic energy is changed to: | HEAT |
| Most of the x-rays produced in a tungsten target are: | Bremsstrahlung |
| At 55 kVp, _____ of the x-rays produced are bremsstrahlung. | 100 % |
| Penetration will result in which shades of the radiographic image? | Dark to black |
| Penetration is more likely with which photon energy? | high |
| Which of the following equates to patient dose? | absorption |
| Differential absorption primarily involves which interaction? | photoelectric |
| The problem with scatter is that it strikes the image receptor in the wrong place. | true |
| Which of the following affects quantity? | 1, 2& 3: kVp, Mas, Distance |
| What happens to quality as mAs increases? | unaffected by mAs |
| Which of the following would increase both the quantity and quality of the primary beam? | kVp |
| The reduction in x-ray photon intensity as it passes through material is termed: | Attenuation |
| Basically, an x-ray image results from: | ALL THE ABOVE: direct transmission of x-ray photons, photoelectric absorption, differential absorption |
| Classical interactions are also known as | Thomson and coherent scattering |
| Coherent scattering involves | an x-ray photon with low energy |
| The x-ray photon produced during classical scattering | is the same energy as the incident photon |
| The x-ray photon produced during classical scattering | travels in a different direction than the incoming photon |
| Most classical scatter photons | are absorbed in the body |
| In reference to patient radiation dose, classical scatter interactions | slightly increase dose |
| The effect of classical scatter interactions on image quality | is minimal |
| Compton scattering involves the x-ray photon | removing a middle- or outer-shell electron. |
| Compton scattering typically occurs with x-ray photons in the energy range of | 20–40 keV. |
| Compton scattering typically occurs with | moderate-energy photons. |
| With Compton scattering, the incident photon | loses up to one third of its energy. |
| Compton scattering results in | ALL OF THESE: a Compton electron, a secondary electron, a Compton scatter photon |
| If a middle-shell electron is removed during a Compton interaction | ALL OF THESE: secondary photons are produce, a secondary electron is ejected, a Compton scatter photon is produced |
| The x-ray photons that are produced as a result of a characteristic cascade during a Compton interaction | are characteristic x-ray photons |
| Secondary photons produced during a Compton interaction | contribute to patient dose |
| The Compton electron | has enough energy to produce further interactions |
| The Compton scatter photon | may exit the patient as part of the remnant radiation and has enough energy to produce further interactions. |
| When it does interact with the image receptor, the Compton scatter photon contributes no useful information because | it has changed direction |
| The fog seen on the radiographic image is the result of | Compton interactions |
| Reducing the amount of Compton scattering | is very important in producing quality images |
| The greater the angle of deflection of a Compton scatter photon: | the lower the energy of the photon |
| No matter which direction the Compton scatter photon goes, it retains approximately | two thirds of its energy |
| The major source of radiation exposure to technologists is due to | Compton interactions |
| The primary source of radiation exposure to the radiographer who is in the room during an exposure is | from scatter from the patient |
| To minimize occupational exposure, the technologist should | wear protective apparel ( lead aprons, gloves, etc) when in the room during imaging |
| For photoelectric interactions to occur, the energy of the incident photon | may be the same or greater than the binding energy of an inner-shell electron |
| After a photoelectric interaction, the incident photon | loses all of its energy and no longer exists |
| During a photoelectric interaction, | an inner-shell electron is ejected |
| The end product(s) of a photoelectric interaction is (are) | a photoelectron and ionized atom |
| The energy of the photoelectron is equal to | the energy of the incident photon minus the binding energy of the orbital electron |
| The energy of the photoelectron is the least as a result of a photoelectric interaction in | bone |
| Photoelectric interactions | contribute significantly to patient dose |
| Secondary x-ray photons are the result of | Compton and photoelectric interaction produce secondary photons |
| Photoelectric interactions are more likely to occur in | bone |
| Protective apparel is often made of lead because it | has a high atomic number |
| Barium sulfate is used as a contrast agent to visualize soft tissue structures such as the stomach because it | has a high atomic number |
| Pair production | never occurs during radiographic procedures. |
| Pair production requires an x-ray photon with an energy of at least | 1.02MeV. |
| Pair production occurs when the incident photon interacts with | the nucleus of the atom |
| What is produced as a result of pair production, a(n) | portion and electron only |
| A positron is | a positively charged electron |
| After ejection from the atom’s nucleus, when the positron interacts with an electron | ALL OF THESE : an annihilation event occurs, the electron and positron are both destroyed, two x-ray photons are produce. |
| For photodisintegration to occur, the incident photon must have an energy level of at least | 10 MeV. |
| Photodisintegration occurs when the incident photon interacts with | the nucleus of the atom |
| Following absorption of the incident photon in the atom’s nucleus, a photodisintegration interaction may result in | neutrons and protons being ejected from the nucleus |
| Photodisintegration interactions | never occur during radiographic procedures |
| To produce a radiographic image that represents anatomy, there must be | ALL OF THESE: photoelectric interactions, transmitted photons, differential absorption |
| Radiation interacting with bone is more likely to be absorbed, resulting in that area of the image being | a light shade of gray |
| Radiation interacting with air is more likely to be _____________, resulting in that area of the image being darker. | transmitted |
| Dense material, like bone, is considered: | radiopaque |
| Air is considered: | radiolucent |
| The greater the absorption of radiation | the greater the patient dose |
| A breakage of the major structure and framework of the macromolecule as a result of an x-ray interaction is called | main-chain scission |
| The most radiosensitive molecule in the body is | DNA |
| Excessive absorption is the result of | using the kVp that is too low for examination |
| T/F.Potential biological damage can occur as a result of a Compton interaction because of the ionization of atoms. | true |
| T/F. The probability of Compton scattering depends on the atomic number of the atom. | false |
| T/F. The probability of Compton scattering depends on the energy level of the incident x-ray photon. | true |
| T/F. All Compton scatter photons travel in the direction of the image receptor. | false |
| T/F. The photoelectric interaction and Compton interaction can both result in a characteristic cascade, producing characteristic radiation. | false |
| T/F. The probability of a photoelectric interaction depends on the atomic number of the atom. | true |
| T/F. The probability of a photoelectric interaction depends on the energy level of the incident x-ray photon. | true |
| T/FThe more the energy of the incident x-ray photon exceeds the binding energy of the inner-shell electron, the greater the probability of a photoelectric interaction. | False |
| T/F.The higher the atomic number of an atom, the greater the probability of a photoelectric interaction. | True |
| T/F. Without differential absorption, the image would be a single shade of gray. | True |
| Which interaction is the major source of occupational exposure? | |
| Which type of interaction will only occur with x-ray energies greater than 10 MeV? | |
| Which interaction do we depend on for radiographic contrast? | |
| Which interaction is the primary contributor to image fog? | |
| The total absorption of an incident photon with the ejection of an inner shell electron is the result of which effect? | |
| Which of the following involves the removal of an orbital electron from an atom of target tissue? | |
| Which of the following is the result of excitation of an orbital electron without removing it from its shell? | |
| Compton scatter is dependent on atomic number. | |
| What happens to photoelectric probability as atomic number increases? | |
| Compton scattering occurs when an incident x-ray photon interacts with a(n): | |
| As the angle of deflection of a Compton scattered photon and the recoil electron is increased from 0° to 180°: | |
| Compton interactions: | |
| Which of the following photon interactions require a minimum energy of 1.02 MeV? | |
| An incident x-ray interacts with an atom without ionization during? | |
| When x-ray photons interact with matter and change direction, the process is called: | |
| The photoelectric process is an interaction between an x-ray photon and: | |
| At energies below 40 keV, the predominant x-ray interaction in soft tissue and bone is _____. | |
| The probability of a photoelectric interaction is higher with: | |
| Absorption will result in which shades of the radiographic image? | |
| What happens to absorption as kVp increases? | |
| What happens to scatter as kVp increases? | |
| If kVp is doubled, what happens to quantity? | |
| Half-value layer is a measure of quality. | |
| Which of the following would absorb the least x-rays? | |
| Which of the following would absorb the most x-rays? | |
| Which of the following would decrease the quantity, but increase the quality of the primary beam? | |
| The reduction in x-ray photon intensity as it passes through material is termed: | |
| When the mass density of an absorber is increased, Photoelectric absorption ______________. | |
| Differential absorption is dependent on (the) _____. | |
| Attenuation is caused by: | |
| The penetrability of an x-ray beam is called x-ray: | |
| The number of useful x-rays in the beam defines x-ray: | |
| An x-ray beam that could pass through dense tissue would have high: | |
| X-ray quantity increases in direct proportion to increases in: |