Chapter: Radiographic Testing Level 2
101.

In order to increase latitude so that thick and thin portions may be radiographed at reasonable viewing densities simultaneously:

A. Fluorescent screen should be employed
B. Led screens should be at least 5 mm thick
C. The cassette may be loaded with two separate films of different speeds
D. Radiograph the object at low energy
Answer» C. The cassette may be loaded with two separate films of different speeds
102.

A dark circle type indication appearing on a radiograph that is the result of the failure of a core support to completely melt is called:

A. A hot tear
B. A gas hole
C. An unfused chaplet
D. A spongy shrink
Answer» C. An unfused chaplet
103.

Dark rounded indications with rather smooth edges appear on the radiograph of casting made in sand mould. These indications would be interpreted as:

A. Slag inclusions
B. Misrun
C. Shrinkage
D. Gas holes
Answer» D. Gas holes
104.

A dark, sharply defined, straight line in the centre of the weld, and running parallel with the length of the weld should be interpreted as:

A. Porosity
B. Incomplete penetration
C. A slag inclusion
D. Lack of fusion
Answer» B. Incomplete penetration
105.

A dark, jagged, linear indication appears on a radiograph of a casting. The area is a transition area between a thick and a thin section. This indication should be interpreted as:

A. A hot tear
B. A gas hole
C. An unfused chaplet
D. A spongy shrink
Answer» A. A hot tear
106.

In a radiograph of a weld there is an indication appearing at the end of the weldbead. It appears as a dark rounded indication with fine small tails coming from around the rounded indication giving it some what of a star-shaped appearance. This would probably be:

A. A crater crack
B. A slag inclusion
C. Root concavity
D. A star crack
Answer» D. A star crack
107.

The density of the radiograph through the weld area is 3.2 while the density in the base metal is 2.9. This would probably indicate:

A. Too high a kV was used
B. Too low a kV was used
C. There is excessive weld reinforcement
D. Weld underfill
Answer» D. Weld underfill
108.

When radiographing a part which contains a crack, it will appear on the radiograph as:

A. A dark continuous line
B. A light, irregular line
C. Either a dark or light line
D. A dark linear indication which could be continuous or intermittent
Answer» D. A dark linear indication which could be continuous or intermittent
109.

If it were necessary to radiograph 18 cm (7 in.) thick steel product, which of the following gamma ray sources would most be used?

A. Cs–137
B. Tm–170
C. Ir–192
D. Co–60
Answer» D. Co–60
110.

Almost all gamma radiography is performed with:

A. Tm-170
B. Natural isotopes
C. Radium
D. Ir-192 or Co-60
Answer» D. Ir-192 or Co-60
111.

The half value layer of lead for Co-60 is approximately 13 mm (0.5 in). If the radiation level on the source side of a 38 mm (1.5 in) lead plate is 0.64 Gy/h (64 R/h):, the radiation level on the opposite side is:

A. 0.08 Gy/h (8 R/h).
B. 0.213 Gy/h (21.33 R/h).
C. 0.107 Gy/h (10.67R/h).
D. 0.32 Gy/h (32 R/h).
Answer» D. 0.32 Gy/h (32 R/h).
112.

The degree of concentration of the radioactive material in gamma ray sources is referred to as the:

A. Atomic weight of the source
B. Half-life of the source
C. Quality of the source
D. Specific activity of the source
Answer» A. Atomic weight of the source
113.

If 37 GBq (1 Ci), of Ir-92 produces dose rate of 0.59 Gy/h (59000 mR/h) at 30.5 cm (1 foot), how much dose in Gy/h (R/h) will 370 GBq (10 Ci) produce at the same distance?

A. 0.59 Gy/h (59000R/h)
B. 0.0059 Gy/h (590 R/h)
C. 5.9 Gy/h (590,000 R/h)
D. 0.00059 Gy/h (59 R/h)
Answer» C. 5.9 Gy/h (590,000 R/h)
114.

Co-59 becomes Co-60 when it is placed in a nuclear reactor where it captures:

A. A proton
B. Contamination
C. Neutron
D. An electron
Answer» C. Neutron
115.

Approximately how long would it take for a 370 GBq (10 Ci) Co-60 source to decay to 92.5 GBq (2.5 Ci)?

A. 5.3 days
B. 5.3 years
C. 10.6 days
D. 10.6 years
Answer» D. 10.6 years
116.

The specific activity of radioactive isotope is expressed in:

A. MeV (million electron-volts)
B. Ci/g (Curies per gram) or Becquerel per kg
C. R/h (Roentgens per hour or gray per hour
D. Counts per minute
Answer» B. Ci/g (Curies per gram) or Becquerel per kg
117.

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» C. Target
118.

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

A. The atomic number of the cathode material
B. The atomic number of the filament material
C. The voltage applied
D. The current flow in the tube
Answer» C. The voltage applied
119.

The primary form of energy conversion when an X ray tube is energized results in the production of:

A. Primary X rays
B. Secondary X ray
C. Short wavelength X ray
D. Heat
Answer» C. Short wavelength X ray
120.

The radiation from 37 GBq (1 Ci) of Co-60 (0.145 Gy or 14.5R at 30.5 cm or 1 foot) is attenuated in air to approximately 5mR/h at a distance of approximately:

A. 914.5 cm (30 feet)
B. 1524 cm (50 feet)
C. 3048 cm (100feet)
D. 6096 cm (200 feet)
Answer» B. 1524 cm (50 feet)
121.

The standard dose rate of a radioactive isotope is expressed in:

A. Roentgens per hour per curie at any standardised distance not exceeding 75 feet
B. Roentgens per hour per curie per foot
C. Roentgens per hour at a distance of one foot
D. Curies per hour
Answer» C. Roentgens per hour at a distance of one foot
122.

At 61 cm (two feet) from a radiation source, radiation intensity is 3 Gy/h (300 R/h). What is the Intensity at 244 cm (8 feet) from the source?

A. 0.12 Gy/h (12R/h)
B. 1.2 Gy/h (120 R/h)
C. 0.1875 Gy/h (18.75 R/h)
D. 0.28 Gy/h (28 R/h)
Answer» C. 0.1875 Gy/h (18.75 R/h)
123.

A good Cobalt-60 shot is made on a 7.6 cm (3 inches) steel casting using an exposure time of 10 minutes and a source-to-film distance of 91.5 (36 inches). If it is necessary to change the source-to-film distance to 61 cm (24 inches), what exposure time would produce a similar radiograph if all other conditions remain the same?

A. 1.6 minutes
B. 4.4 minutes
C. 6.4 minutes
D. 8.8 minutes
Answer» B. 4.4 minutes
124.

A radiographic exposure with 3700 GBq (100 Ci) source of Ir-192 using source to film distance of 60 cm results in a radiation intensity of 0.12 Gy/h (11.8 R/h) and a radiographic density of 2.5. The intensity of radiation needed to obtain the same density when the source to film distance is changed to120 cm is:

A. 0.472 Gy/h (47.2R/h)
B. 0.118 Gy/h (11.8 R/h)
C. 0.029 Gy/h (2.9 R/h)
D. 0.236 Gy/h (23.6 R/h)
Answer» C. 0.029 Gy/h (2.9 R/h)
125.

A 7.6 cm (3 inches) thick test specimen is radiographed with a source having size of 1.3 cm (1/2 inch), the film is placed in contact with the test specimen. The source to film distance is 40.6 cm (16 inches).The geometric unsharpness obtained is:

A. 0.1 cm
B. 0.3 cm
C. 0.5 cm
D. 1.0 cm
Answer» B. 0.3 cm
126.

Radiographic equivalence factors for Inconel and 304 stainless steel are 1.4 and 1.0 respectively. What is the approximate equivalent thickness of Inconel requiring the same exposure as 1.27 cm (½ inch) thickness of 304 stainless steel?

A. 1.27 cm (0.50 inches)
B. 1.78 cm (0.70 inches)
C. 0.9 cm (0.36 inches)
D. 3.55 cm (1.40 inches)
Answer» C. 0.9 cm (0.36 inches)
127.

The approximate radiographic equivalence factors for steel and copper at 220 kV are 1.0 and 1.4 respectively. If it is desirable to radiograph a 1.27 cm (0.5 inch) piece of copper, what thickness of steel would require about the same exposure characteristics?

A. 1.78 cm (0.7 inches)
B. 0.9 cm (0.35 inches)
C. 3.55 cm (1.4 inches)
D. 2.54 cm (1.0 inch)
Answer» A. 1.78 cm (0.7 inches)
128.

If an exposure time of 60 seconds and source to film distance of 365.7 m (1200 feet) 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 457.2 m (1500 feet)?

A. 75 seconds
B. 94 seconds
C. 48 seconds
D. 38 seconds
Answer» B. 94 seconds
129.

Subject contrast and film contrast are the two factors that comprise radiographic:

A. Definition
B. Distortion
C. Contrast
D. Graininess
Answer» C. Contrast
130.

‘Film contrast’ is the inherent ability of a film to show for a given change in film exposure.

A. No appreciable change in density
B. Graininess
C. A difference in density
D. No graininess
Answer» C. A difference in density
131.

The range of the specimen thickness that can be adequately recorded on a radiograph is known as the of the radiograph.

A. Sensitivity
B. Latitude
C. Accuracy
D. Intensity
Answer» B. Latitude
132.

Source-to-object distance, object-to-film distance, and source size are the three factors that control the of the radiograph.

A. Density
B. Exposure
C. Film size
D. Unsharpness
Answer» D. Unsharpness
133.

The ‘multi-film’ technique may be used when one radiograph film does not have enough to produce a satisfactory radiograph of a specimen.

A. Latitude
B. Definition
C. Graininess
D. Activity
Answer» A. Latitude
134.

What governs the penetrating power of an X ray beam?

A. Kilovoltage
B. Time
C. Activity
D. Milliamperage
Answer» A. Kilovoltage
135.

The shorter the wavelength of X or gamma rays:

A. The higher their energy
B. The faster they travel
C. The smaller their penetrating power
D. The closer they are to becoming radio waves
Answer» A. The higher their energy
136.

A large source size can be compensated for by:

A. Increasing source-to-specimen distance
B. Addition of lead screens
C. Increasing specimen-to-film distance
D. Increasing penumbra
Answer» A. Increasing source-to-specimen distance
137.

The maximum film density to which the radiograph should be exposed is dependent upon:

A. The quality of the film viewer
B. The variation in thickness of the specimen
C. The speed of the film
D. The graininess of the film
Answer» A. The quality of the film viewer
138.

The selection of the proper source-to-film distance is a primary factor in controlling:

A. Contrast
B. Unsharpness
C. Graininess
D. Scatter
Answer» B. Unsharpness
139.

When the penumbra on a radiograph measures less than 0.5 mm (0.020 inches), the image will appear to unaided eye of the film interpreter as:

A. Fuzzy
B. Sharp
C. Distorted
D. Dark
Answer» B. Sharp
140.

Two X ray machines operating at same nominal kilovoltage and milliamperage settings:

A. Will produce the same intensities and energies of radiation
B. Will produce the same intensities but produce different energies of radiation
C. Will produce the same energies but may produce different intensities of radiation
D. May give not only different intensities, but also different energies of radiation
Answer» D. May give not only different intensities, but also different energies of radiation
141.

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

A. X ray transformers
B. X ray tubes
C. Masks
D. Radiation detection equipment
Answer» D. Radiation detection equipment
142.

A weld discontinuity which consists of unmelted joint surfaces at the root, and which may be caused by poor fit-up, is called:

A. Hot short cracking
B. A slag inclusion
C. Incomplete penetration
D. Burn through
Answer» C. Incomplete penetration
143.

Which of the following welding discontinuities would be most difficult to image radiographically:

A. Planar lack of fusion
B. Incomplete penetration
C. Undercut
D. Slag inclusions
Answer» A. Planar lack of fusion
144.

The average energy of a Ir-192 source is approximately:

A. 60-80 keV
B. 660 keV
C. 400 keV
D. 1.2 MeV
Answer» D. 1.2 MeV
145.

The half-life of Th-170 is approximately:

A. 74 days
B. 129 days
C. 5.3 years
D. 30.1 years
Answer» B. 129 days
146.

If the required exposure time for a 50 Curie Ir-192 source is 4 minutes, what exposure time would be required at 25 Curie source:

A. 4 minutes
B. 8 minutes
C. 2 minutes
D. 16 minutes
Answer» B. 8 minutes
147.

Which of the following is not a function of the lead screen placed around radiographic film?

A. Increase the photographic action on the film
B. Selectively absorbs scattered radiation
C. Intensifies effects of the primary radiation beam
D. To mask the test piece
Answer» B. Selectively absorbs scattered radiation
148.

Which of the following is a function of the lead screen placed around radiographic film?

A. Masks the test piece
B. Improves geometric unsharpness
C. Intensifies effects of the primary radiation beam
D. None of the above
Answer» C. Intensifies effects of the primary radiation beam
149.

What is the best advantage achieved in exposure time, using front and back lead screens, as compared to exposure time without screens?

A. About the same, but less scatter
B. About twice as great, but less scatter
C. 1/2 to 1/3
D. Not related
Answer» C. 1/2 to 1/3
150.

Gamma ray or high voltage X ray radiography, using film without lead screens, is likely to result in:

A. Mottling of the film
B. Increased geometric unsharpness
C. No apparent difference, but increased exposure time
D. No apparent difference, but decreased exposure time
Answer» A. Mottling of the film
151.

An advantage of a double versus a single emulsion film is:

A. It is higher speed
B. It is finer grained
C. It is lower speed
D. None of the above
Answer» A. It is higher speed
152.

A radiograph is made using film X with an exposure of 10 mA-min. Film density in the area of interest is 1.0. If it is desired to achieve a density of 2.0 in the area of interest, what exposure is required? (Log relative exposure = 1.1 for a density of 1.0 and 1.62 for a density of 2.0)

A. 41.67 mA-min
B. 10 mA-min
C. 12.6 mA-min
D. 33.1 mA-min
Answer» D. 33.1 mA-min
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