RT Flashcards
Q/A
- Although there may be other reasons for using calcium tungstate screens in industrial radiography, they are most usually used to:
a. improve definition and resolution in radiographic
images
b. improve contrast in radiographic images
c. decrease exposure time
d. make films respond to multimillion volt radiation
c. decrease exposure time
- An excellent radiograph is obtained under given conditions of exposure with the film located at a distance of 91 cm (36 in.) from the target of the X-ray tube. If the film is now placed only 46 cm (18 in.) from the target, and all exposure conditions except time are held constant, the new exposure time will be:
a. unchanged
b. longer by approximately 80 percent
c. shorter by approximately 55 percent
d. only about 25 percent as long as the original exposure time
d. only about 25 percent as long as the original
exposure time
- An excellent radiograph is obtained under given exposure conditions with a tube current of 5 mA and an exposure time of 12 minutes. If other conditions are not changed, what exposure time would be required if the X-ray tube current could be raised to 10mA?
a. 24 minutes
b. 12 minutes
c. 6 minutes
d. 3 minutes
c. 6 minutes
- In film radiography, penetrameters are usually placed:
a. between the intensifying screen and the film
b. on the source side of the test object
c. on the film side of the test object
d. between the operator and the radiation source
b. on the source side of the test object
- When radiographing to the 2-2T quality Ievel, an ASTM penetrameter for 13 mm (0.5 in.) thick 2024 aluminium alloy has a thickness of:
a. 13 mm (0.5 in.)
b. 5 x 10-5m (2 mils)
c. 13 x 10-5m (5 mils)
d. 25 X 10-5 m (10 mils)
d. 25 X 10-5 m (10 mils)
- The penetrating ability of an X-ray beam is governed by:
a. kilovoltage
b. time
c. milliamperage
d. source-to-film distance
a. kilovoltage
- Co-60 used in nondestructive testing emits:
a. alpha particles
b. neutrons
c. gamma rays
d. X-rays
c. gamma rays
- A densitometer is an instrument for measuring:
a. X-ray intensity
b. film density
c. density of a material
d. tube current
b. film density
- Three liquids which are essential to process an exposed film properly are:
a. stop bath, acetic acid, and water
b. developer, stop bath, and H2O2
c. developer, fixer, and water
d. acetic acid, fixer, and stop bath
c. developer, fixer, and water
- The two most common causes for excessively high-density radiographs are:
a. insufficient washing and overdevelopment
b. contaminated fixer and insufficient washing
c. overexposure and contaminated fixer
d. overexposure and overdevelopment
d. overexposure and overdevelopment
- The time required for one-half of the atoms in a particular sample of radioactive material to disintegrate is called:
a. the inverse square law
b. a curie
c. a half-life
d. the exposure time
c. a half-life
- What does the term R/h refer to when speaking of intensity?
a. radiation limits for humans
b. roentgens per hour
c. X-rays per hour
d. radiation in hydrogen
b. roentgens per hour
- The ability to detect a small discontinuity or flaw is called:
a. radiographic contrast
b. radiographic sensitivity
c. radiographic density
d. radiographic resolution
b. radiographic sensitivity
- Movement, geometry, and screen contact are three factors that affect radiographic:
a. contrast
b. unsharpness
c. reticulation
d. density
b. unsharpness
- The difference between the densities of two areas of a radiograph is called:
a. radiographic contrast
b. subject contrast
c. film contrast
d. definition
a. radiographic contrast
- The most widely used unit of measurement for measuring the rate at which the output of a gamma ray source decays is the:
a. curie
b. roentgen
c. half-life
d. MeV.
a. curie
- Exposure to X-rays or gamma rays:
a. may have acumulative effect which must be
considered
b. will be beneficial since they build up an immunity
to radiation poisoning
c. will have no effect on human beings
d. will have only a short-term effect on human
tissues
a. may have acumulative effect which must be
considered
- Which dose would be dangerous, if not fatal, if applied to the entire body in a short period of time?
a. 1.5-15 R (4-38 x 10-4 C/kg)
b. 25-70R
c. 200-800 R
d. all of the above doses would most likely be fatal
c. 200-800 R
- When doing gamma ray radiography with high-intensity emitters, the sources are best handled:
a. directly by personnel equipped with special
protective clothing
b. by remote handling equipment
c. directly by personnel with special protective
clothing except when radiographs are being
made
d. by the same methods used for low-intensity
emitters
b. by remote handling equipment
- If a film is placed in a developer solution and allowed to develop without any agitation:
a. the radiograph will not show proper contrast
b. it will be impossible to fix the radiograph
permanently
c. there will be a general “fogging” condition over
the entire radiograph
d. there will be a tendency for areas to affect each
other
d. there will be a tendency for areas to affect each
other
- The selection of the proper type of film to be used for the X-ray examination of a particular part depends on:
a. the thickness of the part
b. the material of the specimen
c. the voltage range of the available X-ray machine
d. all of the above
d. all of the above
- A Co-60 source has a half-life of:
a. 1.2 years
b. 6 months
c. 5.3 years
d. 75 days
c. 5.3 years
- X-ray tube current is controlled by:
a. the current passing through the filament
b. the distance from the cathode to the anode
c. the type of material used in the target
d. the voltage and waveform applied to the X-ray tube
a. the current passing through the filament
- The voltage and waveform applied to the X-ray tube by a high-voltage transformer primarily determines the:
a. quantity of radiation
b. duration of exposure
c. penetrating ability
d. X-ray beam divergence
c. penetrating ability
- Lead foil in direct contact with X-ray film:
a. intensifies the scatter radiation more than the
primary radiation
b. decreases the contrast of the radiographic image
c. intensifies the primary radiation more than the
scatter radiation
d. should not be used when gamma rays are
emitted by the source of radiation
c. intensifies the primary radiation more than the
scatter radiation
- Fluorescent intensifying screens are usually mounted in pairs in rigid holders called:
a. film racks
b. cassettes
c. emulsifiers
d. diaphragms
b. cassettes
- Radiographic sensitivity, in the context of the minimum detectable flaw size, depends on:
a. graininess of the film
b. the unsharpness of the flaw image in the film
c. the contrast of the flaw image on the film
d. all of the above
d. all of the above
- In order to decrease geometric unsharpness:
a. radiation should proceed from as small a focal
spot as other considerations will allow
b. radiation should proceed from as large a focal
spot as other considerations will allow
c. the film should be as far as possible from the
object being radiographed
d. the distance from the anode to the material
examined should be as small as is practical
a. radiation should proceed from as small a focal
spot as other considerations will allow
- As the kilovoltage applied to the X-ray tube is raised:
a. X-rays of longer wavelength and more
penetrating power are produced
b. X-rays of shorter wavelength and more penetrating
power are produced
c. X-rays of shorter wavelength and less penetrating
power are produced
d. X-rays of longer wavelength and less penetrating
power are produced
b. X-rays of shorter wavelength and more penetrating
power are produced
- In order to increase the intensity of X-radiation:
a. the tube current should be increased
b. the tube current should be decreased
c. the test specimen should be moved farther from
the film
d. a lower kilovoltage should be applied to the tube
a. the tube current should be increased
- Primary radiation which strikes a film holder or cassette through a thin portion of the specimen will cause scattering into the shadows of the adjacent thicker portions producing an effect called:
a. radiation imaging
b. spotting
c. undercut
d. unsharpness
c. undercut
- Which of the following materials is suitable for use in vessels or pails and used to mix processing solutions?
a. stainless steel
b. aluminum
c. galvanized iron
d. tin
a. stainless steel
- Scattered radiation caused by any material, such as a wall or floor, on the film side of the specimen is referred to as:
a. primary scattering
b. undercut
c. reflected scattering
d. backscattered radiation
d. backscattered radiation
- Of the following, which would be especially sensitive to injury by excessive exposure to X-or gamma rays?
a. blood
b. lens of the eye
c. internal organs
d. all of the above
d. all of the above
- X-ray exposure may be due to:
a. the direct beam from the X-ray tube target
b. scatter radiation arising from objects in the direct beam
c. both a and b
d. both a and b plus residual radiation that exists for the first few minutes after the X-ray machine has been returned to the “off’’ position
c. both a and b
- A general rule often employed for determining the kilovoltage to be used when X-raying a part is that:
a. the kilovoltage should be as high as other factors will permit
b. the kilovoltage should be as low as other factors will permit
c. the kilovoltage is always a fixed value and cannot be changed
d. the kilovoltage is not an important variable and can be changed over a wide range without affecting the radiograph
b. the kilovoltage should be as low as other factors will permit
If a piece of lead 13 mm (0.5 in.) thick is placed in the path of a beam of radiation emanating from Co-60, it will reduce the dose rate at a given location by:
a. one-third
b. one-quarter
c. one-half
d. three-quarters
c. one-half
- Excessive exposure of film to light prior to development of the film will most likely result in:
a. a foggy film
b. poor definition
c. streaks
d. yellow stain
a. a foggy film
- Reticulation resulting in a puckered or net-like film surface is probably caused by:
a. crimping film after exposure
b. sudden extreme temperature change while processing
c. water or developer on unprocessed film
d. excessive object-to-film distance
b. sudden extreme temperature change while processing
- Frilling or loosening of the emulsion from the base of the film is most likely caused by:
a. water or developer on unprocessed film
b. low temperature of processing solutions
c. developer solution contamination
d. warm or exhausted fixer solution
d. warm or exhausted fixer solution
- If an exposure time of 60 seconds was necessary using a 1.2 m_(4 ft) source-to-film distance for a particular exposure, what time would be necessary if a 0.6 m (2 ft) source-to-film distance is used and all other variables remain the same?
a. 120 s
b. 30s
c. 15 s
d. 240s
c. 15 s
- One of the general rules concerning the application of geometric principles of shadow formation to radiography is:
a. the X-rays should proceed from as large a focal
spot as other considerations will allow
b. the film should be as far as possible from the object
being radiographed
c. the distance between the anode and the material
examined should always be as great as possible
d. all of the above
c. the distance between the anode and the material
examined should always be as great as possible
- As a check on the adequacy of the radiographic
technique, it is customary to place a standard test piece on the source side of the specimen. This standard test piece is called a:
a. reference plate
b. lead screen
c. penetrameter
d. illuminator
c. penetrameter
- The duration of an exposure is usually controlled by:
a. controlling the milliamperage
b. a timer
c. controlling the source-to-film distance
d. a choke coil in the filament transfonner
b. a timer
- A penetrameter is used to indicate the:
a. size of discontinuities in a part
b. density of the film
c. amount of film contrast
d. quality of the radiographic technique
d. quality of the radiographic technique
- A fluorescent intensifying screen will:
a. transform X-ray energy into visible or ultraviolet
light
b. result in reticulation
c. decrease the graininess of the image when using
gamma rays
d. increase the definition in a radiograph
a. transform X-ray energy into visible or ultraviolet
light
- The three main steps in processing a radiograph are:
a. developing, frilling, and fixation
b. developing, fixation, and washing
c. exposure, developing, and fixation
d. developing, reticulating, and fixation
b. developing, fixation, and washing
- Kilovoltage, exposure time, and source-to-film distance are three of the most important X-ray exposure factors that can be controlled. A fourth such exposure factor is:
a. focal point size
b. temperature
c. filament-to-focal spot distance
d. milliamperage
d. milliamperage
- When the minute silver grains on which the X-ray film image is formed group together in relatively large masses, they produce a visual impression called:
a. air bells
b. graininess
c. reticulation
d. frilling
b. graininess