RT LEVEL II 153 Cards Harold Bennett 2025 Flashcards
ASNT RT LEVEL II
Low voltage X-ray tubes are generally fitted with windows made of:
Beryllium
A monochromatic X-ray beam:
Is a beam consisting of a single wavelength.
The general method of producing X-rays involves the sudden deceleration of high-velocity electrons in a solid body called a:
Target
If it were necessary to radiograph a 7-inch thick steel product, which of the following gamma-ray sources would most likely be used?
Cobalt-60
A Cobalt-60 gamma-ray source has an approximate practical thickness limit of:
9 inches of steel or its equivalent.
The absorption of gamma rays from a given source when passing through matter depends on:
The atomic number, density, and thickness of the matter.
The fact that gases, when bombarded by radiation, ionize and become electrical conductors makes them useful in:
Radiation detection equipment.
The velocity of electrons striking the target in an X-ray tube is a function of:
The voltage difference between the cathode and anode.
The uneven distribution of developed grains within the emulsion of a processed X-ray film causes the subjective impression of:
Graininess
Of the following, the source providing the most penetrating radiation is:
15 MeV X-ray betatron
The gamma-ray intensity at one foot from a one-curie source of radioactive cobalt-60 is nearest:
14.9 roentgens per hour
Valve tubes are used in X-ray equipment to:
Provide Necessary Rectification
A good cobalt-60 radiograph is made on a 3-inch steel casting using an exposure time of 10 minutes and a source-to-film distance of 36 inches. If the source-to-film distance is changed to 24 inches, what exposure time would produce a similar radiograph?
4.4 minutes.
When sharp, black bird-foot-shaped marks appear at random on radiographs, they are probably caused by:
Static charges caused by friction.
The adjustment of tube current in conventional X-ray tube circuits is made by:
Adjusting The Filament Heating Current
In comparison with lower-voltage radiographs, high-energy radiographs show:
Greater latitude.
Filters used at the port of the X-ray tube:
Filter out “soft” radiation to provide a more homogeneous X-ray beam.
An ASTM penetrameter for use when inspecting a one-half inch thick steel plate to the 2-2T quality level using a 15-inch source-to-film distance would be made of:
10 mil thick steel.
The kilovoltage applied to an X-ray tube affects:
Both The Quality And Intensity Of The Beam
Filters placed between the X-ray tube and specimen tend to reduce scatter radiation by:
Absorbing longer wavelength components of the primary beam.
Besides serving as a filter, screens of high atomic number, such as lead and lead antimony, also:
Provide some image-intensifying action.
The range of thickness over which densities are satisfactory for interpretation is a measure of the:
Latitude of a radiograph.
Almost all gamma radiography is performed with:
Iridium-192 or Cobalt-60.
The amount of unsharpness or blurring of a radiograph is:
Directly Proportional To The Focal Spot Size And Inversely Proportional To The Source-To-Object Distance
Images of discontinuities close to the source side of the specimen become less clearly defined as:
The thickness of the specimen increases.
The inherent filtration of an X-ray tube is a function of:
The thickness and composition of the X-ray tube port.
X-ray films with large grain size:
Have higher speeds than those with small grain size.
As the effective energy of radiation increases up to about 250kV:
Film graininess increases.
The specific activity of cobalt-60 depends on:
The time the material has been in the reactor.
The most commonly used target material in an X-ray tube is:
Tungsten.
The purpose of a rotating, disc-shaped target in some X-ray tubes is to:
Increase the permissible load.
A device designed to guide and accelerate electrons in a circular orbit to very high energies is called a:
Betatron.
Two isotopic sources of the same strength but different specific activities will:
Have different physical sizes.
A gas-filled region in an electrical field created by electrodes with a potential difference forms the main part of:
An ionization chamber.
Two serious obstacles to high-sensitivity fluoroscopy are:
Limited brightness and large grain size of screens.
In general, the quality of fluoroscopic equipment is best determined by:
Penetrameter sensitivity measurements.
A method for increasing brightness in fluoroscopic testing involves:
An image amplifier or intensifier.
A rule for applying geometric shadow principles states:
The central ray should be as nearly perpendicular to the film as possible.
In order to utilize the principles of geometric enlargement (placing the film at a distance from the specimen):
The source of radiation must be extremely small.
The X-ray absorption of a specimen depends on:
Both the thickness, density, and atomic number of the material.
The radiographic absorption of a material will tend to become less dependent on the composition of the material when:
The kilovoltage is increased.
The formula (milliamperes × time) / (distance²) is:
The exposure factor.
The load that can be handled by an X-ray tube focal spot is governed by:
The focal spot size and the efficiency of the anode cooling system.
X-ray exposure holders and cassettes often incorporate a sheet of lead foil in the back to:
Protect the film from backscatter.
A lead sheet containing a pinhole may be placed halfway between the X-ray tube and the film to:
Determine the approximate size of the focal spot.
The most common way of cooling the anode of a high-power X-ray tube is:
Circulation of water or oil.
In certain cases, packing lead shot around a specimen is done to:
Decrease the effect of scattered radiation undercutting the specimen.
The mottling caused by diffraction when radiographing large-grained metallic specimens can be reduced by:
Raising the kilovoltage and using lead foil screens.
When radiographing steel less than one inch thick:
A 250 kV X-ray machine provides greater sensitivity than cobalt-60.
To increase the film density from 0.8 to 2.0, with a reference log E difference of 0.76 and an antilog of 5.8, the required exposure time is:
69.6 mA per minute.
The absorption of radiation by a material varies:
Exponentially with material thickness.
In the microradiographic technique:
Soft X-rays are used, with kilovoltage between 5 and 50 kV, and fine-grained photographic material.
For a radiograph to have a penetrameter sensitivity of 2-2T or better:
The procedure must define the 2T hole, 2% of specimen thickness.
The characteristic curve shape of an X-ray film is:
Independent of radiation quality.
The term for total absorption of the beam by the X-ray tube wall, housing, and surrounding materials is:
Inherent filtration.
The interval from placing a film in fixer solution to when yellow milkiness disappears is:
Clearing time.
Excessive subject contrast due to wide thickness variation can be corrected by:
Increasing kilovoltage and using filters or longer exposure.
Poor definition may be caused by:
Improper geometric factors, poor film-screen contact, or graininess.
To minimize operator fatigue in fluoroscopy:
Change operators periodically.
The X-ray generator that produces the narrowest cone of radiation is:
25 MeV.
Increasing radiation energy while maintaining other conditions will:
Result in little change in film graininess.
Radiographic film mottling from steel welds using a 15 MeV betatron may occur due to:
Failure to use a lead screen.
A basic difference between radiograph and fluoroscopic images is:
A fluoroscopic image is positive, while a radiograph is a negative transparency.
The quantity of radiation striking a unit area of film is:
The product of radiation intensity and time.
A factor that does not significantly influence radiographic image density is:
Film size.
A 1,000 kVp X-ray machine with lead foil screens has a practical thickness limit of:
5 inches of steel.
Geometrical factors cause unsharpness at indication edges, referred to as:
Penumbral shadow.
Two factors affecting X-ray tube target suitability are:
Atomic number and melting point.
The reason the exposure time must be increased by a factor of four when the source-to-film distance is doubled is:
The intensity of radiation is inversely proportional to the square of the distance from the source to the film.
The approximate radiographic equivalence factors for steel and copper at 220kV are 1.0 and 1.4, respectively. If it is desirable to radiograph a 0.5-inch plate of copper, what thickness of steel would require about the same exposure characteristics?
0.7 inches of steel
Which of the following technique variables is most commonly used to adjust subject contrast?
Kilovoltage
Films left between lead screens too long in high-temperature and high-humidity environments may:
Become fogged
The quantitative measure of film blackening is referred to as:
Photographic density
A curve relating density with the logarithm of exposure or relative exposure is called:
An H & D curve
Subject contrast is affected by:
Thickness differences, radiation quality, and scattered radiation (all of the above).
The Code of Federal Regulations requires all shipping containers for radioisotopes to:
Be fire-resistant.
Which instrument exhibits the best sensitivity for detecting small leaks in a radiation barrier?
A Geiger counter
At voltages above 400 kV, if lead protection presents problems, which material is most likely used instead?
Concrete
A qualitative term for the smallest detectable detail in a radiograph is:
Radiographic sensitivity
The slope of a characteristic curve measures:
Film contrast
A radiographic method producing a 3D effect from two separate exposures is called:
Stereoradiography
A method estimating the depth of a discontinuity by two exposures and computing shifts in shadows is:
The parallax method of depth location
Constant agitation of the developer during processing may:
Cause undesirable preferential flow paths.
The activity of fixer diminishes over time because:
Soluble silver salts accumulate in the solution.
In radiographic processing, the hourly water flow in the wash tank should be:
Four to eight times the tank volume.
Attenuation of gamma rays in commonly tested energy ranges occurs through:
Photoelectric and Compton absorption (both).
A zinc-cadmium sulfide fluoroscopic screen exposed to UV radiation for long periods will:
Become discolored and lose brilliance.
Increasing X-ray or gamma-ray energy will:
Have little effect on the shape of a characteristic curve.
As development time increases:
The characteristic curve becomes steeper and shifts left.
A distinctive trait of high-voltage radiography is:
Its applicability to thick or highly absorbing specimens.
Lead screens are used for nearly all high-voltage radiography exposures because:
They eliminate less-penetrating, shorter wavelengths.
Each solid crystalline substance produces its characteristic X-ray pattern, forming the basis of:
X-ray powder diffraction examination.
The type of glass most likely used as an X-ray barrier in fluoroscopic equipment is:
Lead glass
The maximum practical speed for scanning an object in fluoroscopic testing is:
About 3 inches per second
A change in tube current alters radiation intensity, but the relationship is not exactly proportional because:
Voltage and waveform vary with load in the transformer.
A backscatter image of the cassette superimposed on the specimen is caused by:
Backscatter radiation
Scatter due to X-ray diffraction in a specimen with large grains creates:
A mottled appearance in the radiograph.
If the half-value layer of lead for cobalt-60 is 0.5 inches and the radiation on one side of a 1.5-inch lead plate is 64 R/hr, what is the radiation level on the opposite side?
8 R/hr
Which is not a factor determining subject contrast?
Type of film used
If an exposure time of 60 seconds and a source-to-film distance of 4 feet were necessary, what exposure time would be needed at 5 feet?
94 seconds
To increase latitude so that thick and thin portions may be radiographed simultaneously:
The film cassette may be loaded with two films of different speeds.
Developer solution should be discarded when the quantity of replenisher added equals:
Two to three times the original quantity of developer.
If a specimen were radiographed at 40 kV and 50 kV with time compensation for density, what would be true?
The 50 kV exposure would have lower contrast and greater latitude.
A 250 kVp X-ray machine with lead foil screens has a practical thickness limit of:
2 inches of steel or its equivalent.
The concentration of radioactive material in a gamma-ray source is referred to as:
Specific activity.
In million-volt radiography, filtration at the tube:
Offers no improvement in radiographic quality.
Units of measurement expressing gamma-ray energy include:
Kiloelectron volt (KeV) or million electron volt (MeV).
Film selection for an X-ray exposure depends on:
Thickness, material of the specimen, and X-ray machine voltage range (all of the above).
To increase radiation intensity while using an X-ray tube:
Tube current should be increased.
Lead screens in contact with film serve to:
Increase photographic action, absorb longer wavelengths, and intensify the primary radiation’s effect (all of the above).
Mottling due to diffraction can be reduced or eliminated by:
Raising the kilovoltage and using lead foil screens.
Unsharpness caused by geometrical factors is referred to as:
Penumbral shadow.
The purpose of X-ray generator controls is to:
Enable the operator to control intensity, quality, and exposure duration.
Fluoroscopic screens are damaged by:
UV radiation or sunlight exposure.
A change in silver halide crystals when struck by radiation is called:
A latent image.
If one curie of iridium-192 produces 5900 mR/hr at 1 foot, how much will 10 curies produce at the same distance?
59,000 mR/hr
Factors for selecting source-to-film distance include:
Source size, specimen thickness, and geometric unsharpness.
On a radiograph of a pipe weld, a light irregular image may indicate:
Tungsten inclusion.
A larger source may produce equivalent quality if:
Source-to-film distance is increased.
A light image of a “B” on a processed radiograph indicates:
Backscatter.
Cobalt-59 becomes cobalt-60 by capturing:
A neutron.
When faster-speed film replaces slower film for economic reasons:
Image resolution decreases.
For a given change in exposure, film contrast shows:
A difference in density.
The ability of a material to block or partially block the passage of X-rays and gamma rays is referred to as:
Absorption
Source size, specimen thickness, and source-to-specimen distance are the three factors that determine the:
Unsharpness recorded on the radiograph.
The range of specimen thickness that can be adequately recorded on the radiograph is referred to as the:
Latitude of the radiograph.
Approximately how long would it take for a 10-curie cobalt-60 source to decay to 2.5 curies?
10.6 years
The “photoelectric” effect involves:
Complete absorption of a photon.
Radiographic undercutting is caused by:
Side scatter.
The developer solution is:
Alkaline.
A general rule for applying geometric shadow principles is:
The central ray should be as perpendicular to the film as possible, and the focal spot should be as small as possible.
An iridium-192 gamma-ray source has an approximate practical thickness limit of:
3 inches of steel or its equivalent.
The half-life of radioactive cesium-137 is:
30 years.
The slope of the H & D curve of a radiographic film is called:
Gamma or gradient.
An X-ray film having wide latitude also has:
Low contrast.
The projected area of the target of an X-ray tube is called:
Effective focal spot.
The focal spot in an X-ray tube:
Should be as small as possible without unduly shortening the life of the tube.
In an X-ray tube, the filament and focusing cup are the two essential parts of the:
Cathode.
The quantity of radiation which will produce, by means of ionization, one electrostatic unit of electricity in 0.001293 grams of dry air is known as:
A roentgen.
The specific activity of an isotopic source is usually measured in:
Curies per gram.
Which of the following isotopes has the longest half-life?
Cesium-137.
The primary form of energy conversion when electrons strike a target in an X-ray tube results in the production of:
Heat.
The slope of a straight line joining two points of specified densities on a characteristic curve of a film is known as the:
Average gradient.
An X-ray film having wide latitude also has, by definition:
Low contrast.
The purpose of circulating oil in some types of X-ray tubes is:
To dissipate heat.
An X-ray tube with a small focal spot is considered better than one with a large focal spot when it is defined to obtain:
Better definition.
One method of reducing radiographic contrast is to:
Decrease the wavelength of the radiation used.
Thin sheets of lead foil in intimate contact with X-ray film during exposure increase film density because:
They emit electrons when exposed to X- and gamma radiation.
X-ray tubes are often enclosed in a shockproof casing in order to:
Protect the operator from high-voltage shock.
An X-ray tube rated for 250 kV can be operated at a maximum of:
250,000 volts peak voltage.
A voltage selector with a single winding and various taps for adjustment is called:
An autotransformer.
In X-ray radiography, alternating current must be changed to pulsating direct current for unidirectional flow. This is achieved using:
Rectifiers.
When radiographing to the 2-2T quality level, an ASTM penetrameter for 2.5-inch steel has a thickness of:
50 mils.
