rad physics homework questions quiz
what is produced when the projectile electron excites an outer shell electron? a. brems xray b. characteristic xray c. radiant energy d. heat e. photoelectric xray
d. heat
Two positive 0.5 C charges are positioned 1.0 m apart. The force acting between them is: a. attractive b. exponential c. neutral d. repulsive e. variable
d. repulsive
An electrostatic force is created when a(n): a. Electrostatic charge exists. b. Neutron approaches a neutron. c. Neutron approaches an electron. d. Proton approaches a neutron. e. Proton approaches a proton.
e. Proton approaches a proton
which of the following are not affected by electrostatically charged matter? a. alpha particles b. beta particles c. electrons d. protons e. xrays
e. xrays
A 39 keV x-ray interacts through photoelectric effect with a K-shell electron of barium (binding energy = 37 keV). Therefore: a. The photoelectron will have 2 keV energy b. The photoelectron will have 37 keV energy c. The photoelectron will have 39 keV energy d. The scattered x-ray will have 2 keV energy e. The scattered x-ray will have 37 keV energy
a. The photoelectron will have 2 keV energy
when iron is fabricated into a magnet, magnetic domains: a. align b. cancel c. disappear d. induce e. magnify
a. align
most xray tubes used for radiography: a. are dual focus b. do not emit leakage radiation c. have a fixed anode d. operate in the space charge limited mode e. use tungsten filaments that do not vaporize
a. are dual focus
electrification is the addition of what? a. electric charge b. photons c. protons d. protons and neutrons e. voltage
a. electric charge
one ampere is equal to: a. 1 ohm/s b. 1 C/s c. 1 eV/s d. 1 J/s e. 1 V/s
b. 1 C/s
in the US, normal household current is: a. 60V, 110 Hz b. 110V, 60Hz c. 50V, 120Hz d. 120 V, 50 Hz
b. 110 V 60 Hz
what is the transformer that looks like a square donut called? a. auto b. closed core c. high frequency d. induction e. shell type
b. closed core
the ability of a moving body to do work is called: a. static energy b. potential energy c. kinetic energy d. wave energy
c. kinetic energy
The unit of electrostatic force is the: a. coulomb b. eV c. Joule d. newton e. rad
d. newton
the electric current intensity produce by a DC generator is: a. constant and changing direction b. constant and in one direction c. pulsating and changing direction d. pulsating in one direction e. time varying
d. pulsating in one direction
the efficiency of brems xray production increases w/ increasing: a. collimation b. filtration c. mA d. SID e. target atomic number
d. target atomic number
the unit of electric potential is the: a. ampere b. coulomb c. joule d. ohm e. volt
e. volt
photoelectric interaction with soft tissue is most likely with which of the following?: a. 0.3 kev b. 3.0 kev c. 30 kev d. 300 kev e. 3000 kev
a. 0.3 kev
if a 50W bulb is operated at 100V, the current flowing through that bulb is: a. 0.5 A b. 2 A c. 50 A d. 5000 A
a. 0.5 A
You have a series electrical circuit with 220 volts applied and four resistances of the following values: R1 =12 ohms R2 = 20 ohms R3 = 20 ohms R4 = 4 ohms What is the total circuit current? a. 3.9 A b. 4.7 A c. 5.5 A d. 7.2 A e. 10 A
a. 3.9A
during operation at 80kvp, which of the following photoelectric interactions is most probable: a. 30 kev xray w/ bone b. 30 kev xray w/ fat c. 50 kev xray and lung d. 70 kev xray w/ bone e. 70 kev xray w/ fat
a. 30 kev xray w/ bone
which of the following xrays would most likely undergo classical scattering? a. 5 keV b. 15 keV c. 35 keV d. 66 keV e. 85 keV
a. 5 keV
the quality of photoelectric effect varies as what function of xray energy (E)? a. E^-3 b. E^-2 c. E d. E^2 e. E^3
a. E^-3
The magnitude of the electrostatic force is: a. Inversely proportional to the distance between charges squared. b. Inversely proportional to the square of the charges. c. Proportional to charge times distance. d. Proportional to the distance between charges squared. e. Proportional to the square of the charges.
a. Inversely proportional to the distance between charges squared.
Which of the following accurately represents the transformer law? a. Is/Ip = Np/Ns b. Is/Ip = Ns/Np c. Is/Ip = Vs/Vp d. Ip/Is = Vp/Vs e. Ip/Is = Np/Ns
a. Is/Ip = Np/Ns
When a tungsten-targeted x-ray tube is operated at 68 KVp (3 phase, 6 pulse): a. K-shell characteristic xrays cannot be produced b. L-shell xrays cannot be produced c. One possible K-shell characteristic x-ray will have 12 keV of energy. d. Some projectile electrons may have 70 keV of energy. e. Some projectile electrons may have 45 keV of energy.
a. K-shell characteristic xrays cannot be produced
The turns ratio is defined as: a. Number of secondary windings ÷ primary windings b. Primary iron core ÷ secondary iron core c. Primary voltage ÷ secondary voltage d. Primary windings ÷ number of secondary windings e. Secondary current ÷ primary current
a. Number of secondary windings ÷ primary windings
in an electric generator, a. a coil of wire is rotated in a magnetic field b. a transformer is charged c. ac is changed to dc d. chemical energy is converted to electrical energy e. electrical energy is converted to mechanical energy
a. a coil of wire is rotated in a magnetic field
which of the following will create the most electrical resistance: a. a long wire w/ small diameter b. a short wire w/ small diameter c. a long wire w/ large diameter d. a short wire w/ large diameter
a. a long wire with small diameter
when electrons move in a copper wire: a. a resistance to the electron flow exists b. electrification occurs c. the condition is called electromagnetic force. d. the condition is called electrostatics e. they move down the middle of the wire.
a. a resistance to the electron flow exists
the photoelectric effect is principally associated with: a. absorption of an xray b. brems xray production c. characteristic xray production d. electron excitation e. scattering of an xray
a. absorption of an xray
electric current produced by an AC generator has: a. alternating positive and negative intensity b. constant negative intensity c. constant positive intensity d. pulsating negative intensity e. pulsating positive intensity
a. alternating positive and negative intensity
most magnets: a. are affected by another magnetic field b. are diamagnetic c. are naturally occurring if used in science/tech d. have north, south, and neutral poles e. have positive, negative, and neutral poles
a. are affected by another magnetic field
characteristic xrays: a. are characteristic of the target Z# b. are characteristic of the filter material c. are characteristic of voltage waveform d. have a velocity from zero to the speed of light e. vary in energy as kvp varies
a. are characteristic of the target Z#
the wavelength of an xray: a. becomes longer as projectile electron kinetic energy is reduced b. becomes longer with increasing projectile electron energy c. is longer than that of UV light d. is longst when projectile electron loses all its kinetic energy e. is directly proportional to its frequency
a. becomes longer as projectile electron kinetic energy is reduced
which of the following is not one of the basic xray interactions with matter? a. brems b. classical scattering c. compton scattering d. photodisintigration e. photoelectric effect
a. brems
if a radiographic technique is 74kvp/80mAs, a. brems xray increases if the voltage increases to 84kvp b. brems xrays are emitted at discrete energies c. brems xrays have a max energy of 80keV d. characteristic xray energy increases if voltage is increased to 84kvp e. characteristic xrays are emitted only at 74keV
a. brems xray increases if the voltage increases to 84kvp
static electricity: a. can make one's hair stand on end b. can produce xrays c. can result in magnetism d. is the basis for transformer operation e. is the study of electric currents
a. can make one's hair stand on end
which of the following is required for a DC electric motor? a. commutator ring b. magnet c. ohmmeter d. voltmeter e. ammeter
a. commutator ring
which of the following is required for a direct current electrical generator? a. commutator ring b. diode c. voltmeter d. source of EMF e. transformer
a. commutator ring
electrostatics: a. concerns resting electric charges b. concerns the mass-energy conversion of electrons c. governs the movement of electric charges in a conductor d. is the conversion of kinetic energy e. is the study of photon radiation
a. concerns resting electric charges
brems radiation is produced by: a. conversion of projectile electron kinetic energy to electromagnetic energy b. conversion of target electron kinetic energy into electromagnetic energy c. intrashell electron transitions d. projectile electron target electron interactions e. target electron nuclear interaction
a. conversion of projectile electron kinetic energy to electromagnetic energy
the probability an xray will undergo compton interaction: a. decreases w/ increasing xray energy b. increases w/ decreasing electron energy c. increases w/ increasing electron energy d. increases w/ increasing xray energy e. increases w/ increasing target Z number
a. decreases w/ increasing xray energy
which of the following is normally measured in volts? a. electric potential b. electromagnetic force c. electromagnetic potential d. electromagnetic radiation e. electrostatic force
a. electric potential
which of the following would be classified as electromechanical devices: a. generators and motors b. generators and rectifiers c. motors and rectifiers d. transformers and electromagnets e. transformers and electromagnets
a. generators and motors
an autotransformer: a. has a single coil serving as both primary and secondary coils b. controls xray tube current c. is a shell type transformer d. is an electromechanical device e. is used to control frequency
a. has a single coil serving as both primary and secondary coils
tungsten is the material of choice for anodes because of its: a. high atomic number b. high rpm c. high xray intensity d. low atomic number e. low rpm
a. high atomic number
when a projectile electron enters a target atom and interacts with the nuclear force field: a. it decreases in velocity b. it increases in velocity c. it ionizes the atom d. it ionizes the nucleus e. it removes an inner-shell electron
a. it decreases in velocity
in order to determine the direction of magnetic field that surrounds a current carrying conductor, which rule must be used? a. left hand rule b. right hand rule c. faraday's law d. oersted's law
a. left hand rule
if a bar magnet were suspended in space and another bar of nonmagnetic material were brought close to it, what would happen? a. nothing b. the bar magnet would be attracted c. the bar magnet would become demagnetized d. the bar magnet would rotate e. the imaginary magnetic field lines would be deviated
a. nothing
a transformer operates: a. on AC but not DC b. on both AC and DC c. on DC but not AC d. only above its critical current e. only on a constant voltage
a. on AC but not DC
This formula is used to determine total resistance in what type of circuit? R1 + R2 + R3 = RT a. series b. parallel c. complex d. any of the above
a. series
The flow of 1 C/s in a conductor is equal to: a. 1 ohm b. 1 amp c. 1 eV d. 1 kVp e. 1 V
b. 1 amp
If a 45 keV x-ray interacts with the K-shell electron in an atom of molybdenum (Eb = 20 keV) and ejects it with 8 keV energy, what will be the energy of the scattered x-ray? a. 12 kev b. 17 kev c. 25 kev d. 37 kev e. 45 kev
b. 17 kev
Calculate power for the following series circuit. 100 volts, 20 amps, 3 resistors of 1, 2, and 2 ohms respectively. a. 28,000 watts b. 2000 watts c. 84,000 watts d. 143 watts
b. 2000 watts
440 V is supplied to 1000 primary turns of an autotransformer. If the desired output voltage is 100 V, how many secondary turns must be tapped? a. 100 b. 227 c. 454 d. 4400 e. 10,000
b. 227
a radiographic tube is operated at 500 mA. how many electrons per second is this? a. 3.2 x 10 to the ninth power b. 3.2 x 10 to the eighteenth power c. 6.3 x 10 to the ninth power d. 6.3 x 10 to the eighteenth power e. 6.3 x 10 to the twenty seventh power
b. 3.2 x 10 to the eighteenth power
how many electrons are contained in 0.5 microcoulombs? a. 3.2 x 10 to the sixth b. 3.2 x 10 to the twelfth c. 6.3 x 10 to the sixth d. 6.3 x 10 to the twelfth e. 6.3 x 10 to the eighteenth
b. 3.2 x 10 to the twelfth
when the distance between two charged bodies is cut in half, how much will the force between them increase? a. 2x b. 4x c. 6x d. 8x
b. 4x
220 V is supplied to 800 primary turns of an autotransformer. What will be the output voltage across 200 secondary turns? a. 27.5V b. 55V c. 880V d. 1760V e. 3520V
b. 55V
Gold is sometimes used as the target material in special types of radiation-producing systems. Its electron-binding energies are as follows: K-Shell: 81 keV; L-Shell: 14 keV; M-Shell: 3 keV; N-Shell: 1 keV. Which of the following characteristic x-rays would be produced with operation at 90 KVp? a. 12 keV b. 67 keV c. 76 keV d. 87 keV e. 90 keV
b. 67 keV
You have a series electrical circuit with 220 volts applied and four resistances of the following values: R1 =12 ohms R2 = 20 ohms R3 = 20 ohms R4 = 4 ohms What is the approximate voltage across either of the 20 ohm resistors? a. 58V b. 78V c. 93V d. 107V e. 146V
b. 78V
Lead has a K-shell electron binding energy of 88 keV. Therefore: a. An 84 keV x-ray can undergo photoelectric interaction with the K-shell electron b. An 84 keV x-ray can undergo photoelectric interaction with the L-shell electron c. An 87 keV x-ray is more likely to undergo photoelectric interaction with a K-shell electron than is an 84 keV x-ray d. An 87 keV x-ray is more likely to undergo photoelectric interaction with an L-shell electron than is an 84 keV x-ray e. An 87 keV x-ray will be replaced by a 1 keV electron
b. An 84 keV x-ray can undergo photoelectric interaction with the L-shell electron
which of the following equations can be used to calculate electric power consumption? a. P = RI b. P = IV c. P = I^2V d. P = VR
b. P = IV
the lodestone is an example of: a. a magnetic domain b. a natural magnet c. an electromagnet d. demagnetized matter e. paramagnetism
b. a natural magnet
when a brems xray is produced: a. a projectile electron is absorbed b. a projectile electron loses energy c. a target electron is displaced d. a target electron is excited e. a target electron is ionized
b. a projectile electron loses energy
which of the following occurs in a compton interaction? a. an atom is excited b. an atom is ionized c. The recoil electron has kinetic energy equal to the difference between the energy of the incident x-ray and the electron binding energy. d. The recoil electron has kinetic energy equal to the incident x-ray. e. The secondary photon has wavelength equal to the primary x-ray
b. an atom is ionized
as a result of photoelectric interaction: a. an electron is absorbed b. an electron leaves the atom c. an incident xray is scattered d. incident xray leaves the atom w/ more energy e. incident xray leaves the atom w/ reduced energy
b. an electron leaves the atom
when characteristic xrays are produced, the energy is characteristic of: a. atomic number of filter b. atomic number of target c. mass number of target d. mass number of filtration e. orientation of target
b. atomic number of target
useful characteristic xrays are produced in tungsten: a. by excitation of a k shell electron b. by removal of a k-shell electron c. by ionization of an L shell electron d. when a valence electron is removed e. when the projectile electron interacts with an outer shell electron
b. by removal of a k-shell electron
the main difference between an AC and DC electric generator: a. transformer b. commutator ring c. magnet d. source of EMF e. voltmeter
b. commutator ring
a diagnostic xray tube is an example of which of the following: a. cathode b. diode c. tetrode d. anode e. electrode
b. diode
electric charges reside on which surfaces of solid conductors? a. internal surfaces b. external surfaces c. external surfaces in a helix configuration d. charges move from one surface to another
b. external surfaces
the electric generator is most closely associated with experiments conducted by: a. edison b. faraday c. lenz d. oersted e. volta
b. faraday
the cathode beam of an xray tube is the: a. current that heats the filament b. focused electron beam within the tube c. off focus radiation d. primary xray beam e. secondary radiation
b. focused electron beam
compton scattered xrays: a. are helpful in diagnostic radiology b. have lower energy than the incident xray c. improve contrast resolution d. produce image artifacts e. result from brems
b. have lower energy than the incident xray
the large filament is used during radiography when the heat load is: a. high and visibility of detail is important b. high and visibility of detail is less important c. low and high kvp is required d. low and visibility of detail is important e. low and visibility of detail is less important
b. high and visibility of detail is less important
The product of milliamperage and time make up the 'mAs' factor of a radiographic technique. These factors may be altered by which of the following mathematical relationships resulting in the same net mAs? a. a direct proportion b. an inverse proportion c. a relative log proportion d. an inverse square proportion
b. inverse proportion
the compton effect is: a. AKA classical scattering b. the principal source of image noise c. the same as rayleigh scattering d. same as the thomson effect e. source of static marks on film
b. principal source of image noise
amperage is a unit of measure that is used to describe the: a. direction of electrons b. quantity of electrons c. quality of electrons d. all of these
b. quantity of electrons
a transformer with a turns ratio of 1000:1 is: a. step down transformer b. step up transformer c. autotransformer d. used to increase current e. used to reduce voltage
b. step up xfmr
in brems xray production: a. the projectile electron is bound to tungsten b. the projectile electron is from the cathode c. the target electron exists as a free electron d. the target electron is from the cathode e. the target electron is ionized
b. the projectile electron is from the cathode
in a tungsten target xray tube at 90kVp, the most abundant xray energy would be: a. 10 keV characteristic x-ray b. 12 keV characteristic x-ray c. 30 keV bremsstrahlung x-ray d. 69 keV bremsstrahlung x-ray e. 90 keV bremsstrahlung x-ra
c. 30 keV bremsstrahlung x-ray
the n-shell orbit in an atomic formation can hold no more than: a. 32 neutrons b. 8 electrons c. 32 electrons d. 32 protons
c. 32 electrons
If Ei = incident x-ray energy, Es = scattered x-ray energy, Eb = electron binding energy, and EKE = photoelectric kinetic energy, then which of the following is true? a. Ei = Es + Eb +EKE b. Ei = Es - (Eb +EKE) c. Ei = Eb + EKE d. Ei = Eb - EKE e. Ei = EKE - Eb
c. Ei = Eb + EKE
a 35 keV xray will most likely undergo k-shell photoelectric interaction with: a. Barium (Eb = 37 keV) b. Calcium (Eb = 4 keV) c. Iodine (Eb = 33 keV) d. Muscle (Eb < 1 keV) e. Tungsten (Eb = 69 keV)
c. Iodine (Eb = 33 keV)
Objects become electrified because of: a. An excess of protons. b. An excess of neutrons. c. The transfer of electrons. d. The transfer of neutrons. e. The transfer of protons.
c. The transfer of electrons.
which of the following can create a magnetic field? a. a neutron at rest b. a quantum of visible light c. a spinning proton d. a stable atom e. an xray
c. a spinning proton
primary to secondary coupling in a xfmr is enhanced by: a. 60Hx b. AC c. an iron core d. DC e. EMF
c. an iron core
energy of characteristic xrays increases with increasing: a. filtration b. atomic mass of target material c. atomic number of target material d. kvp e. voltage waveform
c. atomic number of target material
which of the following interactions contributes to image noise? a. brems b. characteristic c. compton scatter d. photodisintegration e. photoelectric effect
c. compton scatter
when a charged particle moves in a straight line, a magnetic field is: a. created along the direction of particle motion b. created and has the same sign as the particle c. created perpendicular to the particle motion d. erased e. reversed
c. created perpendicular to the particle motion
an inverse square law relationship between intensity and distance from a source is based upon: a. scatter b. penetration c. divergence d. absorption
c. divergence
an electrified object has: a. an associated magnetic field b. an excess of protons c. electric charges on its surface d. electric charges throughout e. no loose electric charges
c. electric charges on its surface
a coil of wire, induced with a current, wrapped around a magnetic material such as iron is a/n: a. transformer b. rheostat c. electromagnet d. magnet
c. electromagnet
the probability an xray will interact with an outer-shell electron is influenced principally by: a. the atomic number of the absorber b. binding energy of the electron c. energy of the incident xray d. kinetic energy of the electron e. xray production mode
c. energy of the incident xray
when a filament burns out: a. it should be replaced within 30 days b. the filament current goes to maximum c. the filament current goes to zero d. the tube current is maximum e. the xray intensity is maximum
c. filament current goes to 0
when a single line of magnetic flux interacts with a single coil, this is referred to as a: a. single intersection b. flux line interaction c. flux linkage d. electromagnetic conduction
c. flux linkage
when an electric current flows through a wire with resistance, energy is: a. absorbed as heat b. absorbed as light c. generated as heat d. generated as xrays e. transformed to mass
c. generated as heat
a navigational compass: a. has a north pole attracted to the equator b. has a north pole attracted to the magnetic north pole of the earth c. has both a north and south pole d. is usually made of glass e. will not work at the equator
c. has both a north and south pole
when two objects with strongly opposing charges come within close proximity of one another, an electron shift may occur. this is electrification by: a. friction b. contact c. induction d. static electricity
c. induction
which of the following is a method of electrification? a. diffraction b. excitation c. induction d. resonance e. transmission
c. induction
which of the following would likely be classified as ferromagnetic material? a. air b. glass c. iron d. lead e. water
c. iron
the kinetic energy of the projectile electron in an xray tube: a. causes excitation in the vacuum of the xray tube b. causes ionization in the vacuum of the xray tube c. is about 1% efficient in the production of xrays d. is converted to mass e. is totally converted to xray energy
c. is about 1% efficient in the production of xrays
the xray tube current: a. controls xray energy b. flows through both filaments simultaneously c. is controlled by the filament current d. is the current flowing through the filament e. usually varies from 50-1000A
c. is controlled by the filament current
kinetic energy of a projectile electron can be measured in: a. amperes b. coulombs c. joules d. newtons e. rads
c. joules
which of the following statements about xmfrs is correct? a. if there were equal numbers of primary and secondary coil turns, the ratio would be 0 b. in a shell type xfmr, primary and secondary coils are wound on different cores c. laminated xfmr cores are more efficient than unlaminated cores d. autoxfmr controls current e. high voltage xfmer in the xray imaging system is the autoxfmr
c. laminated xfmr cores are more efficient than unlaminated cores
when projectile electron energy is increased: a. characteristic xray energy decreases b. characteristic xray energy increases c. more brems xrays are produced d. more brems xrays are produced, but only at high energies e. more brems xrays are produced, but only at low energies
c. more brems xrays are produced
compton interaction affects image by increasing which of the following: a. contrast resolution b. lattitude c. noise/fog d. spatial resolution e. speed
c. noise/fog
the cathode is: a. a diode b. designed to supply heat c. one of two parts of a diode d. part of the target e. positively charged
c. one of the 2 parts of a diode
xrays are produced when: a. electric current flows through xray tube filament b. projectile electrons bounce off cathode c. projectile electrons interact with target atoms d. target angle is sufficiently large e. xray tube filament is heated to thermionic emission
c. projectile electrons interact with target atoms
if saturation is achieved and filament current is fixed, tube current: a. decreases with use b. falls w/ increasing kvp c. remains fixed d. rises with increasing exposure tiem e. rises w/ increasing kvp
c. remains fixed
which of the following projectile electron-target interactions result in xray emission? a. excitation of inner shell electron b. excitation of outer shell electron c. removal of inner shell electron d. removal of nucleus e. removal of outer shell electron
c. removal of inner shell electron
the physical laws of magnetism: a. include conversion to electricity b. include conservation of magnetism c. require there be a south pole for every north pole d. require there be a south pole for every north pole but only for magnets of certain shapes e. specify a force that increases with increasing distance from the magnet
c. require there be a south pole for every north pole
in an induction motor, the only part to rotate is the: a. cathode b. electromagnet c. rotor d. stator e. wire loop
c. rotor
when a step up transformer is in use: a. primary winding has more turns than secondary winding b. secondary current is greater than primary current c. secondary voltage is greater than primary voltage d. xray tube current is selected e. turns ratio = 1
c. secondary voltage is greater than primary
the effective focal spot is: a. larger than the actual focal spot b. largest on the anode side c. smaller than the actual focal spot d. smallest on the cathode side e: same size as the actual focal spot
c. smaller than the actual focal spot
which of the following statements about motors and generators is true? a. they are electromagnets b. they both require commutators c. they convert energy from one form to another d. they both have primary and secondary windings e. they require direct electric contact between primary and secondary coils
c. they convert energy from one form to another
if a transformer produces a large secondary current from a small primary current: a. power will be increased b. the turns ratio will be > 1 c. the turns ratio will be < 1 d. the voltage will be larger on the secondary side than the primary side e. there will be more windings on the secondary side than on the primary side
c. turns ratio will be < 1
If a radiographic exposure produced 110 mGy at 72" SID, what would the exposure be at 18"? a. 220mGy b. 420 mGy c. 840mGy d. 1760mGy
d. 1760mGy
Calculate the total resistance if the following resistors are connected in 3 separate branches of a parallel circuit. 5 ohms 15 ohms 45 ohms a. 65 ohms b. 34.6 ohms c. 0.2889 ohms d. 3.46 ohms
d. 3.46
You have a series electrical circuit with 220 volts applied and four resistances of the following values: R1 =12 ohms R2 = 20 ohms R3 = 20 ohms R4 = 4 ohms What is the total circuit resistance? a. 16 b. 32 c. 44 d. 56 e. 71
d. 56
Which of the following would be included as one of the basic electrostatic laws? a. Archimedes' principle b. Conversion to magnetism c. Einstein's law d. Electric-charge concentration e. Planck's law
d. Electric-charge concentration
The phenomenon of lightning occurs when: a. Adjacent clouds are electrically neutral. b. Adjacent clouds have negative electrification. c. Adjacent clouds have positive electrification. d. One cloud is positively electrified and an adjacent one is negatively electrified. e. Thunder is heard.
d. One cloud is positively electrified and an adjacent one is negatively electrified.
the transformer changes: a. electric current to voltage b. electric energy to electromagnetic energy c. electric energy to mechanical energy d. mechanical energy to electric energy e. amplitude of voltage
d. amplitude of voltage
magnetism has some properties similar to those of electrostatics, such as: a. both can be converted to mass b. both can be sensed by touch c. both involve proton-type radiation d. both obey the inverse square law e. both refer to iron substances
d. both obey inverse square law
the principal application of a transformer in an xray system is to: a. change AC to DC b. change DC to AC c. change frequency d. change voltage e. produce xrays
d. change voltage
brems xrays are only produced at: a. discrete energies b. energies above characteristic xrays c. energies below characteristic xrays d. energies up to projectile electron energy e. projectile electron kinetic energy
d. energies up to projectile electron energy
where is the magnetic field surrounding a solenoid the strongest? a. in the space surrounding the solenoid b. at the north magnetic pole c. at the south magnetic pole d. in the center of the solenoid
d. in the center of the solenoid
once filament temperature becomes adequate, a further small rise in filament temperature will cause tube current to: a. decrease just a bit b. decrease very much c. increase just a bit d. increase very much e. not change
d. increase very much
efficiency of xray production is: a. approx 5% b. greater than that of heat production c. in excess of 5% d. independent of tube current e. independent of tube voltage
d. independent of tube current
electric insulators: a. consist of materials like silicon and germanium b. convert electric energy to electromagnetic energy c. convert electric energy to heat d. inhibit movement of electric charge e. permit movement of electric charge
d. inhibit movement of electric charge
when a transformer is designed, the change in current is: a. dependent on supply voltage b. directly proportional to voltage change c. in the same direction as the voltage change d. inversely proportional to the turns ratio e. proportional to turns ratio
d. inversely proportional to turns ratio
xray tube current: a. depends on exposure time b. depends on voltage c. increases when kvp is decreased d. is measured in mA rather than A e. is zero when filament current is above thermionic emission
d. is measured in mA rather than A
the focusing cup: a. is on the positive side of the xray tube b. is slightly positive with respect to the filament c. is the grid in a grid controlled xray tube d. is usually made of thoriated tungsten e. selects the filament
d. is usually made of thoriated tungsten
after compton scattering, the scattered xray has: a. higher energy b. higher frequency c. less mass d. longer wavelength e. lower velocity
d. longer wavelength
the output current in a step up transformer is: a. higher than the input current b. independent of the input current c. independent of turns ratio d. lower than input current e. same as input current
d. lower than input current
which of the following is a physical property we cannot sense? a. acceleration b. electric current c. heat d. magnetism e. mass
d. magnetism
if an above average radiographic technique is used: a. excitation of the target is approximately 50% b. ionization of the target is almost complete c. max energy xray is the electron binding energy d. most xrays are brems e. most xrays are characteristic
d. most xrays are brems
the force between the poles of two bar magnets: a. depends on the permeability of matter separating the magnets b. is inversely proportional to the strength of each magnet c. obeys a law similar to Planck's law d. obeys the inverse square law e. varies directly with the distance between them
d. obeys the inverse square law
the electric motor is most closely associated with experiments conducted by: a. edison b. faraday c. lenz d. oersted e. volta
d. oersted
in an induction motor: a. both rotor and stator have windings b. neither rotor nor stator have windings c. only the rotor has windings d. only the stator has windings e. the cathode rotates
d. only the stator has windings
which of the following is a classification of magnetism? a. coulomb b. diploic c. electromagnetism d. paramagnetism e. polar magnetism
d. paramagnetism
the radiographic image is formed principally by: a. classical scattering b. compton scattering c. off focus radiation d. photoelectric interactions e. uniform distribution of remnant xrays
d. photoelectric interactions
in most xray tubes, there are 2 filaments to: a. ensure saturation current b. produce higher energy xrays c. provide 2 electrodes d. provide 2 focal spots e. reduce space charge effects
d. provide 2 focal spots
the main reason for using the line focus principle is to: a. increase heat capacity b. increase xray intensity c. reduce exposure time d. reduce focal spot size e. reduce heel effect
d. reduce focal spot size
If two magnets are brought together, north-to-north poles will _________, whereas north-to-south poles will ________: a. attract/attract b. attract/repel c. not interact/interact d. repel/attract e. repel/repel
d. repel/attract
the ratio of electric potential across a circuit element to the current flowing through that element is called: a. current b. energy c. power d. resistance e. voltage
d. resistance
when a brems xray is emitted: a. a projectile electron is absorbed b. an inner shell electron is removed from target atom c. an outer shell electron is removed from target atom d. results from conversion of kinetic energy e. target atom is ionized
d. results from conversion of kinetic energy
an induction motor is used in the xray tube to: a. control current b. measure mAs c. provide rectification d. rotate the anode e. vary voltage
d. rotate anode
the principle reservoir for excess electric charge is: a. clouds b. lightning rod c. atmosphere d. the earth e. water pipes
d. the earth
in a series circuit: a. ohm's law fails b. only 3 circuit elements are allowed c. the total current is the sum of the individual currents d. the total resistance is the sum of the individual resistances e. the voltage drop across each circuit element is the same
d. the total resistance is the sum of the individual resistances
If two bar magnets suspended in space were brought together, what would happen? a. nothing b. one would rotate c. the north pole of one would point to the north pole of the other d. they would rotate and attract e. they would rotate and repel
d. they would rotate and attract
in electrodynamics, which of the following is a correct expression? a. I = Qt b. R = I^2V c. R = IV d. V = IR e. V = I/R
d. v = ir
the electrical resistance of wire increases as the diameter of the: a. insulator decreases b. insulator increases c. power supply increases d. wire decreases e. wire increases
d. wire decreases
the number of volts required to cause a current of 40A to flow in a circuit with 5ohms resistance is: a. 5 V b. 8 V c. 40 d. 45 e. 200
e. 200
An L-shell electron (Binding Energy = 26 keV) is removed from an atom that has an M-shell Binding Energy of 4 keV and an N-shell Binding Energy of 1 keV. If a free electron fills the vacancy in the L-shell, the characteristic x-ray produced will have an energy of: a. 1 keV b. 4 keV c. 22 keV d. 25 keV e. 26 keV
e. 26
How many total electrons will pass from the cathode to the anode of an x-ray tube if the technique is 84 KVp / 100 mA / 100 ms? a. 6.3 x 10 to the sixth power b. 6.3 x 10 to the ninth power c. 6.3 x 10 to the twelfth power d. 6.3 x 10 to the fifteenth power e. 6.3 x 10 to the sixteenth power
e. 6.3 x 10 to the sixteenth power
The principal electrostatic law states that: a. A neutron will repel a neutron. b. A proton will repel a neutron. c. An electron will repel a neutron. d. An electron will repel a proton. e. An electron will repel an electron.
e. An electron will repel an electron.
ohm's law states that: a. Electric current is the product of voltage and resistance. b. Electric power is equal to current squared times voltage. c. Electric power is equal to voltage times current. d. The electric potential force is equal to current squared times resistance. e. The electric potential force is the product of current and resistance.
e. The electric potential force is the product of current and resistance.
The probability of photoelectric effect varies as what function of target atomic number (Z)? a. Z^-3 b. Z^-2 c. Z d. Z^2 e. Z^3
e. Z^3
the photoelectric effect is: a. a partially exciting event b. a partially ionizing event c. a radiation scattering event d. the complete absorption of an electron w/ subsequent emission of an xray e. complete absorption of an xray w/ subsequent emission of an electron
e. complete absorption of an xray w/ subsequent emission of an electron
in an electric motor: a. a coil of wire is mechanically rotated b. a commutator ring is not necessary c. a transformer is discharged d. ac is changed to dc e. electric current is supplied to a coil of wire
e. electric current is supplied to a coil of wire
the shift of the characteristic xray spectrum to higher energy occurs because of: a. a decrease in voltage ripple b. decrease in kvp c. higher atomic number filter d. increase in kvp e. increase in target atomic number
e. increase in target atomic number
Coulomb's law states that electrostatic force s: a. dependent on mAs b. directly proportional to the square of the distance between charges c. directly proportional to the square of the product of charges d. inversely proportional to the product of charges e. inversely proportional to the square of the distance between charges
e. inversely proportional to the square of the distance between charges
the output intensity of an xray tube: a. increases when filtered b. is limited by k-shell binding energy c. is monoenergetic d. often measured in curies/becquerels e. is primarily due to brems xrays
e. is primarily due to brems xrays
transformers have iron cores to intensify the: a. electric current b. electric potential c. electric power d. electric voltage e. magnetic field
e. magnetic field
which of the following electron transitions results in the most useful bremsstrahlung xray? a. L to K b. M to K c. M to L d. O to K e. none of the above
e. none of the above
if DC is applied to the primary coil of a step up xfmr, what is the result in the secondary coil? a. AC b. increased current c. increased magnetic field d. increased voltage e. nothing
e. nothing
If radiographic technique in a tungsten target at 60 KVp / 80 mAs is changed to 80 KVp / 80 mAs: a. additional filtration is required b. brems xray intensity remains unchanged c. characteristic xray intensity remains unchanged d. number of projectile electrons increases e. number of xrays produced increases
e. number of xrays produced increases
the space charge effect: a. is more pronounced at high kVp b. is more pronounced at low mA c. limits kVp d. occurs in the vicinity of the anode e. occurs in the vicinity of the cathode
e. occurs in the vicinity of the cathode
brems xrays produced in a tungsten targeted xray tube: a. are all diagnostically useful b. are generally less useful than characteristic xrays c. are less intense than characteristic xrays d. are less intense than if produced in molybdenum e. outnumber characteristic xrays
e. outnumber characteristic xrays
the primary purpose of the glass envelope in an xray tube is to: a. control leakage radiation b. control off-focus radiation c. cool the tube d. ensure against electric shock e. provide a vacuum
e. provide a vacuum
the protective housing of an xray tube is designed to: a. control isotropic xray emission b. control scatter radiation c. limit operation to 100kVp or less d. reduce hazard of leakage radiation e. reduce hazard of scatter radiation
e. reduce hazard of leakage radiation
During the Compton effect, most of the incident x-ray energy is given to which of the following? a. characteristic radiation b. excitation c. electron binding energy d. electron mass e. scattered xray
e. scattered xray
which of the following is a transformer type used in xray imaging systems? a. capacitor type b. filament type c. rectifier type d. rotating type e. shell type
e. shell type
which of the following components of a radiography tube is on the positive side? a. cathode b. filament c. focusing cup d. grid e. stator
e. stator
most magnetic materials are: a. also radioactive b. attracted to copper c. bar shaped d. shaped like a horseshoe e. still magnetic when broken
e. still magnetic when broken
in DC electric generators and motors, the commutator ring acts like a : a. converter from DC to AC b. device to vary current c. device to vary voltage d. source of EMF e. switch
e. switch
electric energy can be converted into: a. chemical energy by an xray machine b. electromagnetic energy by a battery c. mechanical energy by a battery d. nuclear energy in a nuclear reactor e. thermal energy by a lamp
e. thermal energy by a lamp
the compton interaction involves "unbound" electrons because a. excitation occurs b. free electrons are ejected c. ionization occurs d. k-shell electrons are not involved e. they have low binding energy
e. they have low binding energy
regarding the movement of an electric charge from one atom to another: a. both positive and negative charges can move b. it must occur in a large atom c. only positive charges move d. usually inner shell electrons move e. usually outer shell electrons move
e. usually outer shell electrons move
the unit of electric potential is the: a. ampere b. coulomb c. newton d. ohm e. volt
e. volt
a transformer "transforms" electric.... a. frequency b. impedance c. power d. resistance e. voltage
e. voltage
which of the following is the best electric insulator? a. aluminum b. copper c. nickel d. water e. wood
e. wood
generally, a small focal spot allows longer exposure times than a large focal spot true false
false
most of the troublesome heat generated in an xray tube occurs at the filament. true false
false
the radiographic rating chart is primarily designed to protect the filament true false
false
the radiographic rating chart reports the time that should elapse between exposures true false
false
high speed rotor permits longer exposure times than the low speed rotor at single phase operation: true false
true
if the intersection of time and kvp falls on the mA curve, that mA is safe. true false
true
it is not possible to exceed the heat capacity of the housing without first exceeding that of the anode true false
true
the earth's magnetic field is strongest: a. at the equator b. at the poles c. in deep space d. in near space e. in the atmosphere above the equator
b. at the poles
small target angles result in which of the following? a. better collimation b. increased heat capacity c. less heel effect d. small FSS e. small space charge
d. small FSS
rotor speed does not influence heat capacity true false
false
the unit of the electrostatic charge is the: a. ampere b. coulomb c. eV d. newton e. volt
b. coulomb
