McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
Chapters
| 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 | |
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