RT / X-ray Level II

Question 1

Low voltage X-ray tubes are generally fitted with windows made of:

a. plastic
b. beryllium
c. glass
d. lead

Answer 1

b. beryllium

Question 2

The projected area of the target of an X-ray tube is called:

a. focal spot
b. focus
c. effective focal spot
d. geometric unsharpness

Answer 2

c. effective focal spot

Question 3

The general method of producing X-rays involves the sudden deceleration of high-velocity electrons in a solid body called a:

a. focus cup
b. filament
c. target
d. cathode

Answer 3

c. target

Question 4

If it were necessary to radiograph a 7 in. thick steel product, which of the following gamma ray sources would most likely be used?

Answer 4

Co-60

Question 5

A Co-60 gamma ray source has an approximate practical thickness limit of:

a. 205 in. of steel or its equivalent
b. 4 in. of steel or its equivalent
c. 8 in. of steel or its equivalent
d. 11 in. of steel or its equivalent

Answer 5

c. 8 in. of steel or its equivalent

Question 6

The absorption of gamma rays from a given source when passing through matter depends on the:

a. atomic number, density, and thickness of the matter
b. Young’s modulus value of the matter
c. Poisson’s ratio value of the matter
d. specific activity value of the source

Answer 6

a. atomic number, density, and thickness of the matter

Question 7

The fact that gases, when bombarded by radiation, ionize and become electrical conductors makes them useful in:

a. X-ray transformers
b. X-ray tubes
c. masks
d. radiation detection equipment

Answer 7

d. radiation detection equipment

Question 8

The velocity of electrons striking the target in an X-ray tube is a function of the:

a. atomic number of the cathode material
b. atomic number of the filament material
c. voltage difference between the cathode and anode
d. current flow in the rectifier circuit

Answer 8

c. voltage difference between the cathode and anode

Question 9

The uneven distribution of developed grains within the emulsion of a processed X-ray film causes the subjective impression of:

a. graininess
b. streaks
c. spots
d. white scum

Answer 9

a. graininess

Question 10

Co-60 is reported to have a half-life of 5.3 years. By how much should exposure time be increased (over that used initially to produce excellent radiographs when the Co-60 source was new) when the source is two years old?

a. no change in exposure time is needed
b. exposure time should be about 11% longer
c. exposure time should be about 31% longer
d. exposure time should be about 62 to 100% longer

Answer 10

c. exposure time should be about 31% longer

Question 11

A source of Ir-192, whose half-life is 75 days, provides an optimum exposure of a given test object today in a period of 20 min. Five months from now, what exposure time would be required for the same radiographic density, under similar exposure conditions?

a. 10 min
b. 20 min
c. 1 h and 20 min
d. 6 h

Answer 11

c. 1 h and 20 min

Question 12

Of the following, the source providing the most penetrating radiation is:

a. Co-60
b. 220 kVp X-ray tube
c. 15 MeV X-ray betatron
d. electrons from Ir-192

Answer 12

c. 15 MeV X-ray betatron

Question 13

The gamma ray intensity at 300 mm (1 ft) from a 37 GBq (1 Ci) source of radioactive Co-60 is nearest to:

a. 150 mSv per hour (15 R per hour)
b. 10,000 mSv per hour (1,000 R per hour)
c. 10 mSv per min (1 R per min)
d. 100 uSv per day (10 mR per day)

Answer 13

a. 150 mSv per hour (15 R per hour)

Question 14

The focal spot in an X-ray tube:

a. is inclined at an angle of 30° from normal to the tube axis
b. is maintained at a high negative voltage during operations
c. should be as large as possible to ensure a narrow beam of primary radiation
d. should be as small as possible without unduly shortening the life of the tube

Answer 14

d. should be as small as possible without unduly shortening the life of the tube

Question 15

In an X-ray tube, the filament and focusing cup are the two essential parts of the:

a. anode
b. cathode
c. rectifier
d. X-ray transformer

Answer 15

b. cathode

Question 16

The quantity of radiation that will produce, by means of ionization, one electrostatic unit of electricity in 0.001293 g of dry air is known as a:

a. millicurie
b. gamma
c. roentgen
d. curie

Answer 16

c. roentgen

Question 17

The specific activity of an isotopic source is usually measured in:

a. million electron volts (MeV)
b. curies per gram (Ci/g)
c. roentgen per hour (R/h)
d. counts per minute (cpm)

Answer 17

b. curies per gram (Ci/g)

Question 18

Which of the following isotopes has the longest half-life?

a. Tm-170
b. Co-60
c. Ir-192
d. Cs-137

Answer 18

d. Cs-137

Question 19

The primary form of energy conversion when electrons strike a target in an X-ray tube results in the production of:

a. primary X-rays
b. secondary X-rays
c. short wavelength X-rays
d. heat

Answer 19

d. heat

Question 20

The slope of a straight line joining two points of specified densities on a characteristic curve of a film is known as the:

a. speed of the curve
b. latitude
c. average gradient
d. density

Answer 20

c. average gradient

Question 21

An X-ray film having wide latitude also has:

a. poor definition
b. low contrast
c. high speed
d. none of the above

Answer 21

b. low contrast

Question 22

The purpose for circulating oil in some types of X-ray tubes is to:

a. lubricate moving parts
b. absorb secondary radiation
c. decrease the need for high current
d. dissipate heat

Answer 22

d. dissipate heat

Question 23

An X-ray tube with a small focal spot is considered better than one with a large focal spot when it is desired to obtain:

a. greater penetrating power
b. better definition
c. less contrast
d. greater film density

Answer 23

b. better definition

Question 24

One method of reducing radiographic contrast is to:

a. increase the distance between the radiation source and the object
b. decrease the distance between the object and the film
c. decrease the wavelength of the radiation used
d. increase development time within manufacturer’s recommendations

Answer 24

c. decrease the wavelength of the radiation used

Question 25

Thin sheets of lead foil in intimate contact with X-ray film during exposure increase film density because they: a. fluoresce and emit visible light which helps expose the film b. absorb the scattered radiation c. prevent backscattered radiation from fogging the film d. emit electrons when exposed to X-radiation and gamma radiation, which help darken the film

Answer 25

d. emit electrons when exposed to X-radiation and gamma radiation, which help darken the film

Question 26

X-ray tubes are often enclosed in a shockproof casing in order to: a. dissipate heat b. protect the operator from high-voltage shock c. shield the tube from secondary radiation d. increase the efficiency of the rectifier

Answer 26

b. protect the operator from high-voltage shock

Question 27

The slope of the characteristic curve of a radiographic film is called: a. speed b. latitude c. gamma or gradient d. density

Answer 27

c. gamma or gradient

Question 28

In X-ray radiography, alternating current must be changed to pulsating direct current in order to satisfy the need for unidirectional current. This change may be accomplished by: a. transformers b. rectifiers c. anodes d. cathodes

Answer 28

b. rectifiers

Question 29

When radiographing to the 2-2T quality level, an ASTM IQI for 2.5 in. steel has a thickness of: a. 0.5 in. b. 0.0025 in. c. 0.005 in. d. 0.05 in.

Answer 29

d. 0.05 in.

Question 30

A good Co-60 radiograph is made on a 3 in. steel casting using an exposure time of 10 min and a source-to-film distance of 36 in. If it is necessary to change the source-to-film distance to 24 in., what exposure time would produce a similar radiograph if all other conditions remain the same? a. 1.6 min b. 4.4 min c. 6.4 min d. 8.8 min

Answer 30

b. 4.4 min

Question 31

When sharp, black, bird-foot shaped marks which are known not to correspond with any discontinuities appear at random on radiographs, they are probably caused by:

Answer 31

static charges caused by friction

Question 32

The adjustment of tube current in conventional X-ray tube circuits is made by: a. adjusting current supplied to filament b. adjusting the target-to-cathode distance c. inserting resistance in the anode lead d. opening the shutter on the X-ray tube port

Answer 32

a. adjusting current supplied to filament

Question 33

In comparison with lower voltage radiographs, high-energy radiographs show: a. greater contrast b. greater latitude c. greater amounts of scatter radiation relative to primary beam intensity d. none of the above

Answer 33

b. greater latitude

Question 34

Filters used at the port of the X-ray tube: a. intensify the X-ray beam by contributing secondary radiation b. filter short wavelength X-ray beams to provide softer radiation c. provide the most readily adjusted means of modifying X-ray intensity d. filter out soft radiation to provide a more homogeneous X-ray beam

Answer 34

d. filter out soft radiation to provide a more homogeneous X-ray beam

Question 35

An ASTM IQI for use when inspecting a 0.5 in. thick steel plate to the 2-2T quality level using a 16 in. source-to-film distance would be made of: a. 0.005 in. thick aluminum b. 0.05 in. thick aluminum or steel c. 0.01 in. thick steel d. 0.002 in. strip of any metallic material

Answer 35

c. 0.01 in. thick steel

Question 36

Filters placed between the X-ray tube and specimen tend to reduce scatter radiation, undercutting the specimen by: a. absorbing the longer wavelength components of the primary beam b. absorbing the shorter wavelength components of the primary beam c. absorbing backscatter radiation d. decreasing the intensity of the beam

Answer 36

a. absorbing the longer wavelength components of the primary beam

Question 37

Besides serving as a filter, screens of high atomic numbers, such as lead and lead antimony, also: a. decrease the source-to-film distance needed for a proper radiograph b. provide some image intensifying action c. permit the use of higher speed film d. decrease the graininess in a radiograph

Answer 37

b. provide some image intensifying action

Question 38

The range of thickness over which densities are obtained that are satisfactory for interpretation is a measure of the: a. subject contrast of a radiograph b. sensitivity of a radiograph c. latitude of a radiograph d. definition of a radiograph

Answer 38

c. latitude of a radiograph

Question 39

Almost all gamma radiography is performed with: a. natural isotopes b. Ir-192 or Co-60 c. radium d. Tm-170

Answer 39

b. Ir-192 or Co-60

Question 40

The amount of unsharpness or blurring of a radiograph is: a. directly proportional to the object-to-film distance and inversely proportional to the size of the focal spot b. directly proportional to the size of the focal spot and inversely proportional to the source-to-object distance c. inversely proportional to the object-to-film distance and directly proportional to the source-to-object distance d. inversely proportional to the size of the focal spot and the object-to-film distance

Answer 40

b. directly proportional to the size of the focal spot and inversely proportional to the source-to-object distance

Question 41

Images of discontinuities close to the source side of the specimen become less clearly defined as: a. source-to-object distance increases b. the thickness of the specimen increases c. the size of the focal spot decreases d. the thickness of the specimen decreases

Answer 41

b. the thickness of the specimen increases

Question 42

X-ray films with large grain size: a. will produce radiographs with better definition than film with small grain size b. have slower speeds than those with a relatively small grain size c. have higher speeds than those with a relatively small grain size d. will take longer to expose properly than film with relatively small grain size

Answer 42

c. have higher speeds than those with a relatively small grain size

Question 43

As the effective energy of the radiation increases: a. film graininess increases b. film graininess decreases c. radiographic definition increases d. film speed decreases

Answer 43

a. film graininess increases

Question 44

The half-life of radioactive Cs-137 is nearest to: a. 36 days b. 6 years c. 30 years d. 526 days

Answer 44

c. 30 years

Question 45

The most commonly used target material in an X-ray tube is: a. copper b. carbon c. carbide d. tungsten

Answer 45

d. tungsten

Question 46

The purpose for including a disc-shaped target that rotates rapidly during operation in some X-ray tubes it to: a. increase the intensity of X-radiation b. decrease the voltage needed for a specific quality of radiation c. increase the permissible load d. none of the above

Answer 46

c. increase the permissible load

Question 47

A device which is basically a combination of magnet and transformer designed to guide and accelerate electrons in a circular orbit to very high energies is called: a. an electrostatic belt generator b. a linear accelerator c. a betatron d. a toroidal electromagnetic type X-ray tube

Answer 47

c. a betatron

Question 48

Two isotropic sources of a given strength have two different specific activity values. The source with the higher specific activity value will: a. have a smaller physical size than the source with a lower specific activity b. have a shorter half-life than the source with a lower specific activity c. produce harder gamma rays than the source with a lower specific activity d. have a larger physical size than the source with the lower specific activity

Answer 48

a. have a smaller physical size than the source with a lower specific activity

Question 49

A gas-filled region located in an electrical field created by electrodes across which a potential difference is applied forms the major portion of: a. a low-voltage X-ray tube b. a megger c. a hot cathode X-ray tube d. an ionization chamber

Answer 49

d. an ionization chamber

Question 50

Two serious obstacles to high-intensity fluoroscopy are: a. the inability to reproduce results and the need for periodic replacement of screens b. the limited brightness and large grain size of fluoroscopic screens c. cost and slow speed d. the need for using long wavelength X-rays and the lack of X-ray intensity associated with this method

Answer 50

b. the limited brightness and large grain size of fluoroscopic screens

Question 51

In general, the quality of fluoroscopic equipment is best determined by: a. densitometer readings b. IQI sensitivity measurements c. discontinuity area measurements d. reference standards

Answer 51

b. IQI sensitivity measurements

Question 52

In fluoroscopic testing, a fundamental difficulty is the relative low brightness level of the images. One method for increasing brightness uses ______ which converts light energy from the initial phosphor surface to electrons, which are in turn accelerated and focused onto a smaller fluorescent screen. a. a betatron b. an electron c. an image amplifier or intensifier d. an electrostatic belt generator

Answer 52

c. an image amplifier or intensifier

Question 53

A general rule governing the application of the geometric principles of shadow formation states that the: a. X-rays should proceed from as large a focal spot as other considerations will allow b. distance between the radiation source and the material examined should be as small as practical c. film should be as far as possible from the object being radiographed d. central ray should be as nearly perpendicular to the film as possible to preserve spatial relationships

Answer 53

d. central ray should be as nearly perpendicular to the film as possible to preserve spatial relationships

Question 54

The developer solution is: a. acidic b. alkaline c. saline d. colloidal

Answer 54

b. alkaline

Question 55

The radiographic absorption of a material will tend to become less dependent upon the composition of the material when: a. the kilovoltage is increased b. the source-to-film distance is decreased c. the kilovoltage is decreased d. a filter is used

Answer 55

a. the kilovoltage is increased

Question 56

The formula (milliamperes x time) ÷ distance² is: a. used to calculate film gradient b. the reciprocity law c. used to determine radiographic contrast d. the exposure factor

Answer 56

d. the exposure factor

Question 57

The load that can be handled by an X-ray tube focal spot is governed by: a. the composition of the cathode b. the size of the focal spot and the efficiency of the cooling system of the anode c. the distance from the anode to the cathode d. the high-voltage waveform

Answer 57

b. the size of the focal spot and the efficiency of the cooling system of the anode

Question 58

X-ray exposure holders and cassettes often incorporate a sheet of lead foil in the back which is not in intimate contact with the film. The purpose of this sheet of lead foil is: a. to act as an intensifying screen b. to protect the film from backscatter c. both a and b d. neither a nor b

Answer 58

b. to protect the film from backscatter

Question 59

A lead sheet containing a pinhole may be placed halfway between the X-ray tube and the film in order to: a. determine the approximate size of focal spot b. measure the intensity of the central ray c. filter scatter radiation d. soften the X-radiation

Answer 59

a. determine the approximate size of focal spot

Question 60

In certain cases, it may be advantageous to pack lead shot around a specimen. The purpose for doing this is to: a. prevent movement of the specimen b. increase the subject contrast c. generate smaller wavelength X-radiation d. decrease the effect of scattered radiation undercutting the specimen

Answer 60

d. decrease the effect of scattered radiation undercutting the specimen

Question 61

When radiographing steel with a thickness less than 1 in.: a. Co-60 would give greater radiographic sensitivity than a 250 kV X-ray machine b. a 250 kV X-ray machine would give greater radiographic sensitivity than Co-60 c. the use of fluorescent screens would result in a radiograph of better quality than would lead foil screens d. the use of lead foil screens will require a shorter exposure time than will fluorescent screens

Answer 61

b. a 250 kV X-ray machine would give greater radiographic sensitivity than Co-60

Question 62

A radiograph made with an exposure of 12 mA per minute has a density of 0.8 in the region of maximum interest. It is desired to increase the density to 2.0 in this area. By reference to a characteristic curve of the film, it is found that the difference in log E, between a density of 0.8 and 2.0 is 0.76. The antilogarithm of log 0.76 is 5.8. What must the new exposure time be to produce a radiograph with a density of 2.0? a. 9.12 mA per minute b. 21.12 mA per minute c. 69.6 mA per minute d. 16 mA per minute

Answer 62

c. 69.6 mA per minute

Question 63

The absorption of radiation by a material varies: a. directly with the square of the distance from the source b. with the thickness of the material c. inversely with the amount of scattering in the material d. in an approximately exponential manner with the thickness of the material

Answer 63

d. in an approximately exponential manner with the thickness of the material

Question 64

In the microradiographic technique: a. soft X-rays are usually used b. a kilovoltage range of 5-50 kV is usually used c. the photographic material is often finer grained than an ordinary X-ray film d. all of the above

Answer 64

d. all of the above

Question 65

In order for a radiograph to have an IQI sensitivity of 2-2T or better: a. the radiographic procedure has to be able to differentiate a 2% difference in specimen thickness b. the radiographic procedure must be able to define the 2T hole in an IQI that is 2% of the thickness of the specimen c. the radiograph must be able to distinguish a discontinuity with a length equivalent to 2% of the specimen thickness d. none of the above

Answer 65

b. the radiographic procedure must be able to define the 2T hole in an IQI that is 2% of the thickness of the specimen

Question 66

For practical purposes, the shape of the characteristic curve of an X-ray film is: a. independent of the type of film used b. independent of the quality of X-radiation or gamma radiation c. drastically changed when the quality of X-ray radiation is changed d. primarily determined by the subject contrast

Answer 66

d. primarily determined by the subject contrast

Question 67

The interval between the time a film is placed in a fixer solution and the time when the original diffuse, yellow milkiness disappears is known as: a. clearing time b. fixing time c. hardening time d. oxidation time

Answer 67

a. clearing time

Question 68

Improper geometric factors, poor contact between film and lead foil screens and graininess of film are possible causes of: a. high film density b. poor definition c. fogged film d. low film density

Answer 68

b. poor definition

Question 69

A radiograph of a steel weldment is made using a 15 MeV betatron. When the radiograph is developed, there is an overall film mottling. A possible cause for such mottling is: a. incorrect exposure time b. excessive object-to-film distance c. failure to use a lead screen during exposure d. excessive exposure to ultraviolet rays

Answer 69

c. failure to use a lead screen during exposure

Question 70

A basic difference between a radiograph and a fluoroscopic image is: a. the fluoroscopic image is more sensitive b. the fluoroscopic image is a positive whereas the radiograph is a negative transparency c. the fluoroscopic image is brighter d. there is no basic difference between the two

Answer 70

b. the fluoroscopic image is a positive whereas the radiograph is a negative transparency

Question 71

A 1000 kVp X-ray machine used in conjunction with a lead foil screen has an approximate practical thickness limit of: a. 1.5 in. of steel or its equivalent b. 3 in. of steel or its equivalent c. 5 in. of steel or its equivalent d. 16 in. of steel or its equivalent

Answer 71

c. 5 in. of steel or its equivalent

Question 72

Because of geometric factors such as source size, source-to-film distance, there can be a lack of perfect sharpness at the edges of indications. The unsharpness caused by geometrical factors may be referred to as the: a. astigmatic effect b. penumbral shadow c. focus variation d. none of the above

Answer 72

b. penumbral shadow

Question 73

Two factors which greatly affect the suitability of the target material in an X-ray tube are: a. tensile strength and yield strength b. melting point and magnetic strength c. electrical resistance and tensile strength d. atomic number and melting point

Answer 73

d. atomic number and melting point

Question 74

The reason the exposure time must be increased by a factor of four when the source-to-film distance is doubled is that: a. the intensity of radiation decreases at an exponential rate when the source-to-film distance is increased b. the quality of radiation is inversely proportional to the square root of the distance from the source to the film c. the intensity of radiation is inversely proportional to the square of the distance from the source to the film d. the scattered radiation effect is greater as the source-to-film distance increases

Answer 74

c. the intensity of radiation is inversely proportional to the square of the distance from the source to the film

Question 75

The most important factor for determining the amount of X-ray absorption of a specimen is the: a. thickness of the specimen b. density of the specimen c. atomic number of the material d. Young's modulus of the material

Answer 75

c. atomic number of the material

Question 76

The approximate radiographic equivalent factors for steel and copper at 220 kV are 1.0 and 1.4 respectively. If it is desirable to radiograph a 0.5 in. plate of copper, what thickness of steel would require about the same exposure characteristics? a. 0.7" of steel b. 0.35" of steel c. 1.4 " of steel d. 1.0" of steel

Answer 76

a. 0.7" of steel

Question 77

Which of the following technique variables is most commonly used to adjust subject contrast? a. source-to-film distance b. milliamperage c. kilovoltage d. focal point size

Answer 77

c. kilovoltage

Question 78

Films that are left between lead screens too long in a high-temperature and high-humidity atmosphere may: a. show increased speed but decreased quality characteristics b. become fogged c. become mottled d. show tree-shaped light areas in the finished radiograph

Answer 78

b. become fogged

Question 79

The quantitative measure of film blackening is referred to as:

Answer 79

photographic density

Question 80

A curve that relates density with the logarithm of exposure or of relative exposure is called: a. a sensitivity curve b. a density-exposure curve c. a characteristic curve d. X-ray intensity curve

Answer 80

c. a characteristic curve

Question 81

Subject contrast is affected by: a. thickness differences in specimen b. radiation quality c. scattered radiation d. all of the above

Answer 81

d. all of the above

Question 82

Which of the following instruments would exhibit the best sensitivity and most likely be used to detect small leaks in a radiation barrier? a. a film badge b. a fountain pen type ionization chamber c. a geiger counter d. a dosimeter

Answer 82

c. a geiger counter

Question 83

At voltages above 400 kV, the use of lead to provide protection may present serious problems. If this is a serious problem, which of the following materials would most likely be used as a substitute? a. aluminum b. concrete c. steel d. boron

Answer 83

b. concrete

Question 84

A qualitative term often used to indicate the size of the smallest detail that can be seen in a radiograph is:

Answer 84

radiographic sensitivity

Question 85

The slope (steepness) of a characteristic curve is a measure of: a. subject contrast b. radiographic definition c. radiographic contrast d. film contrast

Answer 85

d. film contrast

Question 86

A special radiographic method requiring two radiographs taken during separate exposures from two different positions to give the visual impression of a three-dimensional display when viewed in an optical device simultaneously is called: a. fluoroscopy b. xeroradiography c. stereoradiography d. parallel radiography

Answer 86

c. stereoradiography

Question 87

The depth of a discontinuity can be estimated by making two exposures on a single film from two different positions of the X-ray tube. The depth of the discontinuity is computed from the shift in the shadow of the discontinuity with respect to the images of fixed markers on the front and back of the specimen. The method is called: a. stereoradiography b. xeroradiography c. fluoroscopy d. the parallax method of depth location

Answer 87

d. the parallax method of depth location

Question 88

Agitation of the developer during the development process may: a. speed the developing cycle b. help replenish the developer c. cause undesirable, preferential flow of developer along certain paths d. cause reticulation

Answer 88

c. cause undesirable, preferential flow of developer along certain paths

Question 89

The activity of the fixer diminishes after being used for a period of time because the: a. active ingredients evaporate b. active ingredients are absorbed by the radiograph c. fixer solution accumulates soluble silver salts d. active ingredients settle to the bottom of the tank

Answer 89

c. fixer solution accumulates soluble silver salts

Question 90

In processing radiographs, the hourly flow of water in the wash tank should be: a. 2-3 times the volume of the tank b. 4-8 times the volume of the tank c. at least 40 gal per hour d. varied continuously in proportion to the number of radiographs being developed

Answer 90

d. varied continuously in proportion to the number of radiographs being developed

Question 91

The equation for determining geometric unsharpness Ug is Ug/F=d/Do. Which change below will increase the geometric unsharpness? a. source-to-object distance increases b. object-to-film distance increases c. size of radiation source decreases d. thickness of test specimen decreases

Answer 91

b. object-to-film distance increases

Question 92

Increasing the X-ray or gamma-ray energy will: a. significantly decrease the average gradient of a characteristic curve b. significantly increase the average gradient of a characteristic curve c. increase the slope of a characteristic curve d. have little effect on the shape of a characteristic curve

Answer 92

d. have little effect on the shape of a characteristic curve

Question 93

As the development time increases: a. the characteristic curve grows steeper and moves to the left b. the characteristic curve grows steeper and moves to the right c. the characteristic curve remains the same in shape but moves to the left d. there is little effect on the characteristic curve

Answer 93

a. the characteristic curve grows steeper and moves to the left

Question 94

A distinctive characteristic of high-voltage radiography is that: a. it results in comparatively high subject contrast b. it results in comparatively high radiographic contrast c. it is applicable to comparatively thick or highly absorbing specimens d. all of the above are distinctive characteristics of high-voltage radiography

Answer 94

c. it is applicable to comparatively thick or highly absorbing specimens

Question 95

Lead screens are used for almost all exposures when using: a. the fluoroscopic technique b. low-voltage radiography c. high-voltage radiography d. xeroradiography

Answer 95

c. high-voltage radiography

Question 96

Which of the following glasses would most likely be used as an X-ray barrier window on fluoroscopic equipment? a. heat-resistant glass b. lead glass c. optical glass d. barium oxide glass

Answer 96

b. lead glass

Question 97

Radiographic undercutting is caused by: a. side scatter b. poor geometry c. lead screens d. free electrons

Answer 97

a. side scatter

Question 98

When other operating conditions are held constant, a change in tube current causes a charge in radiation intensity emitted from an X-ray tube, the intensity being approximately proportional to tube current. What is the primary factor that prevents this from being exactly proportional? a. the voltage and voltage waveform of an X-ray machine transformer varies with load b. wavelength changes are not exactly proportional c. current cannot be changed at a linear rate d. scatter radiation does not vary at a proportional rate

Answer 98

a. the voltage and voltage waveform of an X-ray machine transformer varies with load

Question 99

When viewing a radiograph, an image of the back of the cassette superimposed on the image of the specimen is noted. This is most likely due to: a. undercut b. overexposure c. the X-ray intensity was too high d. backscatter

Answer 99

d. backscatter

Question 100

The half-value layer of lead for Co-60 is approximately 0.5". If the radiation level on the source side of a 1.5" lead plate is 64 R/h, the radiation level on the opposite side is: a. 8 R/h b. 21.33 R/h c. 10.66 R/h d. 32 R/h

Answer 100

a. 8 R/h

Question 101

Which of the following is not a factor in determining subject contrast? a. nature of the specimen b. the radiation quality used c. type of film used d. intensity and distribution of the scattered radiation

Answer 101

c. type of film used

Question 102

If an exposure time of 60 s and a source-to-film distance of 4 ft is necessary for a particular exposure, what exposure time would be needed for an equivalent exposure if the source-to-film distance is changed to 6 ft? a. 27 s b. 49 s c. 135 s d. 400 s

Answer 102

c. 135 s

Question 103

Developer solution should be discarded when the quantity of replenisher added equals: a. the original quantity of developer b. 2-3 times the original quantity of developer c. 5-6 times the original quantity of developer d. 10 times the original quantity of developer

Answer 103

b. 2-3 times the original quantity of developer

Question 104

If a specimen is radiographed at 40 kV and again at 50 kV with time compensation to give the radiographs the same density, which of the following statements would be true? a. the 40 kV exposure would have a lower contrast and a greater latitude than the 50 kV exposure b. the 40 kV exposure would have a higher contrast and a greater latitude than the 50 kV exposure c. the 50 kV exposure would have a lower contrast and a greater latitude than the 40 kV exposure d. the 50 kV exposure would have a higher contrast and a greater latitude than the 40 kV exposure

Answer 104

c. the 50 kV exposure would have a lower contrast and a greater latitude than the 40 kV exposure

Question 105

A 250 kVp X-ray machine used in conjunction with a lead foil screen has an approximate practical thickness limit of: a. 1.5" of steel or its equivalent b. 2.0" of steel or its equivalent c. 6.0" of steel or its equivalent d. 7.5" of steel or its equivalent

Answer 105

b. 2.0" of steel or its equivalent

Question 106

The degree of concentration of the radioactive material in a gamma ray source is referred to as the: a. specific activity of the source b. quality of the source c. atomic weight of the source d. half-life of the source

Answer 106

a. specific activity of the source

Question 107

In million-volt radiography, filtration at the tube: a. increases the generation of short wavelength X-rays b. decreases the generation of short wavelength X-rays c. improves the radiographic quality by decreasing scatter radiation d. offers no improvement in radiographic quality

Answer 107

d. offers no improvement in radiographic quality

Question 108

Film selection for an X-ray exposure depends on: a. the thickness of the part b. the material of the specimen c. the voltage range of the X-ray machine d. all of the above

Answer 108

d. all of the above

Question 109

While using an X-ray tube for radiography, the operator wants to increase the radiation intensity. To do so, the: a. kilovoltage should be lowered b. tube current should be increased c. test specimen should be moved farther from the film d. tube current should be decreased

Answer 109

b. tube current should be increased

Question 110

Lead screens are put in direct contact with the film to: a. increase the photographic action on the film b. absorb the longer wavelength scattered radiation c. intensify the photographic effect of the primary more than the scattered radiation d. do all of the above

Answer 110

d. do all of the above

Question 111

The main purpose of the X-ray generator controls on the equipment is to: a. maintain the direction and width of the X-ray beam b. enable the operator to obtain the intensity, quality, and duration of exposure desired c. allow the operator to adjust film focal distance remotely d. change alternating current to increase X-ray intensity

Answer 111

b. enable the operator to obtain the intensity, quality, and duration of exposure desired

Question 112

When X-rays, gamma rays, light, or electrons strike the photographic emulsion, a change takes place in the silver halide crystals. This change is called: a. photographic density b. photographic sensitivity c. latent image d. characteristic curve

Answer 112

c. latent image

Question 113

With respect to quality, what three factors must be considered in selecting a source-to-film distance? a. source activity, type of film, type of screens b. source activity, size of film, thickness of material c. source size, source activity, specimen-to-film distance d. source size, source side of object-to-film distance, required geometric unsharpness

Answer 113

d. source size, source side of object-to-film distance, required geometric unsharpness

Question 114

On a radiograph of a pipe weld, there is a very light irregularly shaped small image in the weld. This image would most likely be due to the presence of: a. porosity b. slag inclusion c. tungsten inclusion d. inadequate buildup

Answer 114

c. tungsten inclusion

Question 115

A large physical size source may produce an equivalent quality radiograph if: a. the source-to-film distance is increased b. more backing lead is used c. a faster film is used d. exposure time is decreased

Answer 115

a. the source-to-film distance is increased

Question 116

A light image of a backing "B" on a processed radiograph is probably caused by: a. excessive density b. backscatter c. kilovoltage set too low d. poor film handling

Answer 116

b. backscatter

Question 117

Co-59 becomes Co-60 when it is placed in a nuclear reactor where it captures: a. an electron b. a neutron c. a proton d. contamination

Answer 117

b. a neutron

Question 118

When a faster speed film is substituted for a slower one to improve the economics of the exposure, which of the following conditions occurs? a. the film must receive special processing b. the definition will improve c. the image resolution will be reduced d. none of the above will be experienced

Answer 118

c. the image resolution will be reduced

Question 119

For a given change in the radiation exposure, film contrast is the inherent ability to show: a. a difference in density b. no graininess c. graininess d. no appreciable change in density

Answer 119

a. a difference in density

Question 120

The ability of a material to block or partially block the passage of X-rays and gamma rays is called: a. penetration b. absolution c. absorption d. latitude

Answer 120

c. absorption

Question 121

Source size, specimen thickness and source-to-specimen distance are the three factors that determine the: a. density of the radiograph b. exposure of the radiograph c. film size d. unsharpness recorded on the radiograph

Answer 121

d. unsharpness recorded on the radiograph

Question 122

The range of specimen thicknesses that can be adequately recorded on the radiograph is called: a. sensitivity of the radiograph b. latitude of the radiograph c. accuracy of the radiograph d. intensity of the source

Answer 122

b. latitude of the radiograph

Question 123

Approximately how long would it take for a 10 Ci Co-60 source to decay to 2.5 Ci? a. 5.3 years b. 7.9 years c. 10.6 years d. 15.9 years

Answer 123

c. 10.6 years

Question 124

The photoelectric effect involves: a. the visible electromagnetic spectrum b. an electric camera c. complete absorption of a photon d. photodisintegration

Answer 124

c. complete absorption of a photon

Question 125

An exposure technique is established to obtain a 2.0 density using type "D" film and automatic processing at 81° F. In order to obtain comparable results using manual processing at 68° F and 5-min development time, it would be necessary for the original exposure time to be: a. reduced by approximately 30% b. increased by approximately 99% c. increased by approximately 30% d. reduced by approximately 99%

Answer 125

b. increased by approximately 99%