McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
Chapters
| 651. |
An acceptable quality radiograph should include: |
| A. | Proper identification |
| B. | Correct penetrameter and visible holes |
| C. | Location markers |
| D. | All of the above |
| Answer» D. All of the above | |
| 652. |
For gamma ray sources, radiographic intensity is proportional to source activity in gigabecquerels or curies for: |
| A. | All sources |
| B. | Large sources |
| C. | Small sources |
| D. | None of the above |
| Answer» A. All sources | |
| 653. |
Poor contact between lead screens and film is likely to cause: |
| A. | An indistinct or ‘fuzzy’ image |
| B. | A mottled appearance on the film |
| C. | ‘Undercut’ of the test piece image |
| D. | Increased geometric unsharpness |
| Answer» A. An indistinct or ‘fuzzy’ image | |
| 654. |
Which of the following conditions might cause mottling of a radiographic film? |
| A. | Test piece with thickness equal to an integral multiple of the primary beam wavelength |
| B. | Back scatter from aged fluorescent screens |
| C. | Test piece with thickness of the same order of magnitude as the grain size |
| D. | Test piece with thickness equal to an integral multiple of the average grain size |
| Answer» B. Back scatter from aged fluorescent screens | |
| 655. |
A photon-electron interaction in which a photon gives up a portion of its energy to an electron is called: |
| A. | The photoelectric effect |
| B. | The Compton effect |
| C. | Pair production |
| D. | Bremsstrahlung |
| Answer» B. The Compton effect | |
| 656. |
If the radiation intensity is 5.9 Gy/h (590 R/h) at a distance of 30.5 cm (1 foot) from a source, how far is it to the point where the radiation intensity is 0.02 Gy/h (2R/h)? |
| A. | 518 cm (17 feet) |
| B. | 16551 cm (543 feet) |
| C. | 8291 cm (272 feet) |
| D. | 17983 cm (590 feet) |
| Answer» A. 518 cm (17 feet) | |
| 657. |
It is important to initiate the welding arc within the weld groove because: |
| A. | Starting a weld bead outside the groove may overheat the base metal |
| B. | Too rapid heating and cooling of the base metal can cause hard spots which are potential failure initiation sites |
| C. | Starting a weld bead outside the groove results in excessively wide welds |
| D. | None of the above |
| Answer» D. None of the above | |
| 658. |
If the radiation intensity is 5 Gy/h (500 R/h) at a distance of 152.4 cm (5 feet) from a source, how far is it to the point where the radiation intensity is 0.05 Gy/h (5 R/h)? |
| A. | 1676.4 cm (55 feet) |
| B. | 1981 cm (65 feet) |
| C. | 1524 cm (50 feet) |
| D. | 762 cm (25 feet) |
| Answer» C. 1524 cm (50 feet) | |
| 659. |
Which of the following techniques would probably reduce the amount of scattered radiation reaching the film during a radiographic exposure? |
| A. | Using a finer grained film |
| B. | Masking the test piece |
| C. | Removing lead screens |
| D. | All of the above |
| Answer» B. Masking the test piece | |
| 660. |
The lights in a high intensity viewer are typically: |
| A. | Fluorescent |
| B. | Normal incandescent bulbs |
| C. | Photoflood bulbs |
| D. | Mercury vapour lamps |
| Answer» C. Photoflood bulbs | |
| 661. |
The gamma factor of Cs-137 is: |
| A. | 1.37 R·h-1·Ci-1at one metre |
| B. | 0.59 R·h-1·Ci-1at one metre |
| C. | 0.0062 R·h-1·Ci-1at one metre |
| D. | 0.38 R·h-1·Ci-1 at one metre |
| Answer» D. 0.38 R·h-1·Ci-1 at one metre | |
| 662. |
If the required X ray exposure time for a 150 kV, 5 mA exposure is 2 minutes, approximately what exposure time would be required at 10 mA? |
| A. | 1/2 minute |
| B. | 1 minute |
| C. | 2 minutes |
| D. | 4 minutes |
| Answer» B. 1 minute | |
| 663. |
A thin, jagged, dark line inside the weld image on a radiographic film is probably: |
| A. | Incomplete penetration |
| B. | Lack of fusion |
| C. | Burn through |
| D. | A crack |
| Answer» D. A crack | |
| 664. |
A straight, dark line in the centre of a weld bead image on film would be suspected of being: |
| A. | Lack of fusion |
| B. | A crack |
| C. | Incomplete penetration |
| D. | Root concavity |
| Answer» C. Incomplete penetration | |
| 665. |
‘Undercut’ or ‘burned out’ edges of the test piece in film image can usually be reduced by: |
| A. | Increasing source to film distance |
| B. | Decreasing the thickness of the lead screens |
| C. | Placing a thin sheet of lead behind the cassette |
| D. | Masking the test piece |
| Answer» D. Masking the test piece | |
| 666. |
Which of the following would be detrimental to radiographic image sharpness? |
| A. | Small focal spot |
| B. | Large film focal distance |
| C. | Large object to film distance |
| D. | None of the above |
| Answer» C. Large object to film distance | |
| 667. |
Contrast and definition are the two major factors that determine the of the radiograph: |
| A. | Density |
| B. | Sensitivity |
| C. | Graininess |
| D. | Intensity |
| Answer» B. Sensitivity | |
| 668. |
Scatter radiation: |
| A. | Is not controllable |
| B. | Is controllable to some extent, but cannot be completely eliminated |
| C. | Can be eliminated completely by changing the kV |
| D. | Can be eliminated completely by using lead intensifying screens |
| Answer» B. Is controllable to some extent, but cannot be completely eliminated | |
| 669. |
Which of the following factors will affect the definition of the radiographic image? |
| A. | Intensity of radiation |
| B. | Film density |
| C. | Tube current |
| D. | Focal spot size |
| Answer» D. Focal spot size | |
| 670. |
Slow films: |
| A. | Give better definition than fast films |
| B. | Are faster than fast films |
| C. | Require shorter exposure times than fast films |
| D. | Usually have less contrast than fast films |
| Answer» A. Give better definition than fast films | |
| 671. |
Contrast is defined as the comparison between on different areas of the radiograph: |
| A. | Density |
| B. | Sensitivity |
| C. | Sharpness |
| D. | Latitude |
| Answer» A. Density | |
| 672. |
Definition is defined as the measure of the of the outline of the image in the radiograph. |
| A. | Density |
| B. | Sensitivity |
| C. | Sharpness |
| D. | Latitude |
| Answer» C. Sharpness | |
| 673. |
As radiation (X ray or gamma ray) energy is lowered: |
| A. | Radiation of longer wavelength and better penetration is produced |
| B. | Radiation of shorter wavelength and better penetration is produced |
| C. | Radiation of shorter wavelength and less penetration is produced |
| D. | Radiation longer wavelength and less penetration is produced |
| Answer» D. Radiation longer wavelength and less penetration is produced | |
| 674. |
Dark crescent-shaped indications on a radiographic film are most likely caused by: |
| A. | Crimping film after exposure |
| B. | Crimping film before exposure |
| C. | Sudden extreme temperature change while processing |
| D. | Warm or exhausted fixer |
| Answer» A. Crimping film after exposure | |
| 675. |
Lead screen are primarily used to: |
| A. | Improve the quality of the radiography by increasing the effect of scatter radiation |
| B. | Intensify the primary beam |
| C. | Decrease film graininess |
| D. | Reduce density of film |
| Answer» B. Intensify the primary beam | |
| 676. |
Static marks are most often caused by: |
| A. | Film bent when inserted in a cassette or holder |
| B. | Foreign material or dirt imbedded in screens |
| C. | Scratches on lead foil screens |
| D. | Improper film handling techniques |
| Answer» D. Improper film handling techniques | |
| 677. |
When radiographic energy is decreased: |
| A. | The subject contrast decreases |
| B. | The film contrast decreases |
| C. | The subject contrast increases |
| D. | The film contrast decreases |
| Answer» C. The subject contrast increases | |
| 678. |
The major cause for poor definition is: |
| A. | A source-to-film distance which is too long |
| B. | Screens which are too thin |
| C. | Film graininess |
| D. | Too small a source size |
| Answer» C. Film graininess | |
| 679. |
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 | |
| 680. |
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 | |
| 681. |
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 | |
| 682. |
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 | |
| 683. |
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 | |
| 684. |
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 | |
| 685. |
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 | |
| 686. |
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 | |
| 687. |
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 | |
| 688. |
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 | |
| 689. |
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). | |
| 690. |
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 | |
| 691. |
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) | |
| 692. |
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 | |
| 693. |
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 | |
| 694. |
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 | |
| 695. |
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 | |
| 696. |
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 | |
| 697. |
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 | |
| 698. |
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) | |
| 699. |
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 | |
| 700. |
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) | |
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