McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
Chapters
| 601. |
Which of the following would be detrimental to radiographic image sharpness? |
| A. | Small focal spot |
| B. | Small film focal distance |
| C. | Small object to film distance |
| D. | None of the above |
| Answer» B. Small film focal distance | |
| 602. |
A change in which the following parameters would require a new X ray exposure chart? |
| A. | kV |
| B. | X ray machine |
| C. | Test piece thickness |
| D. | All of the above |
| Answer» B. X ray machine | |
| 603. |
If the required exposure time for a 1850 GBq (50 curie) Ir-192 source is 4 minutes, what exposure time would be required for 925 GBq (25 curie) source: |
| A. | 4 minutes |
| B. | 8 minutes |
| C. | 2 minutes |
| D. | 16 minutes |
| Answer» B. 8 minutes | |
| 604. |
A radiograph is made using film X with an exposure of 10 mA-min. Film density obtained 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» A. 41.67 mA-min | |
| 605. |
The least offensive of the following welding discontinuities would probably be: |
| A. | Incomplete penetration |
| B. | Lack of fusion |
| C. | Slag inclusions |
| D. | Porosity |
| Answer» D. Porosity | |
| 606. |
A quantity calculated by the formula, 0.693/(decay constant), is called: |
| A. | Half value layer |
| B. | Mass attenuation constant |
| C. | Half-life |
| D. | Specific activity |
| Answer» C. Half-life | |
| 607. |
The density difference displayed from one area of a film radiograph to another is called: |
| A. | Subject contrast |
| B. | Radiographic contrast |
| C. | Film contrast |
| D. | Film latitude |
| Answer» B. Radiographic contrast | |
| 608. |
The half-life of Co-60 is approximately: |
| A. | 74 days |
| B. | 129 days |
| C. | 5.3 years |
| D. | 30.1 years |
| Answer» C. 5.3 years | |
| 609. |
Increasing the mA setting on an X ray machine: |
| A. | Decreases exposure time |
| B. | Increases exposure time |
| C. | Increases the short wavelength components of the X ray beam |
| D. | Decreases the short wavelength components of the X ray beam |
| Answer» A. Decreases exposure time | |
| 610. |
Which of the following would be considered a film artifact? |
| A. | Excessive film density |
| B. | Light leaks |
| C. | Inadequate penetration |
| D. | Sugar |
| Answer» B. Light leaks | |
| 611. |
Which of the following would be detrimental to radiographic image sharpness? |
| A. | Small focal spot |
| B. | Large film focal distance |
| C. | Small object to film distance |
| D. | None of the above |
| Answer» B. Large film focal distance | |
| 612. |
The half-life of Ir-192 is approximately: |
| A. | 74 days |
| B. | 129 days |
| C. | 5.3 years |
| D. | 30.1 years |
| Answer» A. 74 days | |
| 613. |
A dark crescent shaped mark in the centre of a weld bead radiographic image would probably be: |
| A. | A film artifact |
| B. | Porosity |
| C. | A tungsten inclusion |
| D. | Root concavity |
| Answer» A. A film artifact | |
| 614. |
A photon-nuclear interaction in which energy is converted into sub-atomic particles is called: |
| A. | The photoelectric effect |
| B. | The Compton effect |
| C. | Pair production |
| D. | Bremsstrahlung |
| Answer» C. Pair production | |
| 615. |
An interaction in which radiation is produced by the rapid deceleration of an electron is called: |
| A. | The photoelectric effect |
| B. | The Compton effect |
| C. | Pair production |
| D. | Bremsstrahlung |
| Answer» D. Bremsstrahlung | |
| 616. |
The gamma factor of Tm-170 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-1at one metre |
| Answer» C. 0.0062 R·h-1·Ci-1at one metre | |
| 617. |
An exposed radiographic film which transmits 1% of the light incident on it has what density: |
| A. | 1.0 |
| B. | 2.0 |
| C. | 99.0 |
| D. | 0.5 |
| Answer» C. 99.0 | |
| 618. |
If the radiation intensity is 5 Gy/h (500 R/h) at a distance of 152.4 cm (5 feet) from a source, what is the intensity at 1524 cm (50 feet)? |
| A. | 0.5 Gy/h (50 R/h) |
| B. | 1.0 Gy/h (100 R/h) |
| C. | 0.1 Gy/h (10R/h) |
| D. | 0.05 Gy/h (5 R/h) |
| Answer» D. 0.05 Gy/h (5 R/h) | |
| 619. |
The average energy of a Cs-137 source is approximately: |
| A. | 60-80 keV |
| B. | 660 keV |
| C. | 400 keV |
| D. | 1.2 MeV |
| Answer» B. 660 keV | |
| 620. |
Which of the following is an advantage of X ray over gamma ray sources for radiography? |
| A. | Portability |
| B. | Required maintenance |
| C. | Variable radiation energy |
| D. | All of the above |
| Answer» C. Variable radiation energy | |
| 621. |
The basic purpose of a penetrameter is to: |
| A. | Indicate quality of the radiographic technique |
| B. | Indicate the smallest discontinuity which can be shown by the radiographic technique being used |
| C. | Serve as a comparison standard for evaluating discontinuity size |
| D. | All of the above |
| Answer» A. Indicate quality of the radiographic technique | |
| 622. |
When a casting is being non destructively examined for critical service, and the possibility of cracks exists, which of the following techniques would be best? |
| A. | X ray radiography at 200 kV or less |
| B. | Magnetic Particle or Liquid Penetrant testing |
| C. | Radiography (X or gamma ray, depending on the thickness) |
| D. | Radiography and either Magnetic Particle or liquid Penetrant testing |
| Answer» B. Magnetic Particle or Liquid Penetrant testing | |
| 623. |
Which of the following is an advantage of X ray over gamma ray sources for radiography? |
| A. | Safety |
| B. | Variable radiation intensity |
| C. | Variable radiation energy |
| D. | All of the above |
| Answer» D. All of the above | |
| 624. |
The average energy of a T3-170 source is approximately: |
| A. | 60-80 keV |
| B. | 660 keV |
| C. | 400 keV |
| D. | 1.2 MeV |
| Answer» A. 60-80 keV | |
| 625. |
The gamma factor of Co-60 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-1at one metre |
| Answer» A. 1.37 R·h-1·Ci-1at one metre | |
| 626. |
The intensifying effect of lead screens is mainly caused by: |
| A. | X ray generated by the lead screens |
| B. | Fluorescence of the lead screens |
| C. | Excited electrons |
| D. | The Maxwell effect |
| Answer» C. Excited electrons | |
| 627. |
Which of the following expressions correctly determines radiographic density? |
| A. | Io/It |
| B. | Log (Io/It) |
| C. | Log (Io-It) |
| D. | Io-It |
| Answer» B. Log (Io/It) | |
| 628. |
The most significant difference in two X ray beams produced at different kV settings is: |
| A. | Beam intensity |
| B. | Exposure |
| C. | Wavelength distribution |
| D. | Beam divergence |
| Answer» C. Wavelength distribution | |
| 629. |
Most significant difference in two X ray beams produced at different mA settings is: |
| A. | Penetrating power |
| B. | Wavelength distribution |
| C. | X ray quality |
| D. | Beam intensity |
| Answer» D. Beam intensity | |
| 630. |
Which of the following would be considered a film artifact? |
| A. | Excessive film density |
| B. | Insufficient film density |
| C. | Insufficient definition (penetrameter holes) |
| D. | Static marks |
| Answer» D. Static marks | |
| 631. |
Natural discontinuities comparable in size to the penetrameter holes shown on a radiograph may not be detected because: |
| A. | Natural discontinuities may contain less dense material than the penetrameter holes |
| B. | Natural discontinuities may be thicker than the penetrameter holes |
| C. | Natural discontinuities do not necessarily have as sharp edges as the penetrameter holes |
| D. | All of the above |
| Answer» C. Natural discontinuities do not necessarily have as sharp edges as the penetrameter holes | |
| 632. |
If the radiation intensity is 1 Gy/h (100 R/h) at a distance of 152.4 cm (5 feet) from a source, what is the intensity at 610 cm (20 feet)? |
| A. | 0.0625 Gy/h (6.25 R/h) |
| B. | 0.25 Gy/h (25 R/h) |
| C. | 16 Gy/h (1600 R/h) |
| D. | 4 Gy/h (400 R/h) |
| Answer» A. 0.0625 Gy/h (6.25 R/h) | |
| 633. |
Fluorescent screens are seldom used in industrial radiography because: |
| A. | Light leaks degrade the film image |
| B. | Film fogging can result if used in the vicinity of fluorescent lights |
| C. | Poor definition and screen mottle can result |
| D. | None of the above |
| Answer» C. Poor definition and screen mottle can result | |
| 634. |
Calculate geometric unsharpness for the following conditions: Source size = 2 mm × 2 mm; SFD = 700 mm; test piece thickness = 25 mm |
| A. | 0.6 mm |
| B. | 0.06 mm |
| C. | 6,0 mm |
| D. | 0.15 mm |
| Answer» D. 0.15 mm | |
| 635. |
The gamma factor of Ir-192 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-1at one metre |
| Answer» B. 0.59 R·h-1·Ci-1at one metre | |
| 636. |
A test piece with large differences in thickness would have: |
| A. | High film contrast |
| B. | High subject contrast |
| C. | Low subject contrast |
| D. | Low film contrast |
| Answer» B. High subject contrast | |
| 637. |
A quantity expressed by the formula, 0.693/(absorption co-efficient) is called: |
| A. | Half value layer |
| B. | Mass attenuation constant |
| C. | Half-life |
| D. | Specific activity |
| Answer» A. Half value layer | |
| 638. |
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. | Using a filtered X ray beam |
| C. | Removing lead screens |
| D. | All of the above |
| Answer» B. Using a filtered X ray beam | |
| 639. |
A radiographic indication in a weld, characterised by two parallel dark lines in the film image, would probably be caused by: |
| A. | Incomplete penetration |
| B. | Lack of fusion |
| C. | Slag inclusions |
| D. | Tungsten inclusions |
| Answer» B. Lack of fusion | |
| 640. |
To produce the sharpest image, which of the following should be true? |
| A. | The radiographic source should be small |
| B. | The radiographic source should be as close as possible to the test piece |
| C. | The planes of the test piece and the film should be at oblique angles to each other |
| D. | All of the above |
| Answer» A. The radiographic source should be small | |
| 641. |
‘Undercut’ or ‘burned out’ edges of the test piece film image are caused by: |
| A. | Geometric unsharpness |
| B. | Scattered radiation |
| C. | Inadequate source to film distance |
| D. | Old film |
| Answer» B. Scattered radiation | |
| 642. |
Which of the following is an advantage of gamma ray over X ray sources for radiography? |
| A. | Portability |
| B. | No external power supply needed |
| C. | Ruggedness |
| D. | All of the above |
| Answer» D. All of the above | |
| 643. |
The intensifying effects of fluorescent screens are caused by: |
| A. | Electron emission |
| B. | Light emission |
| C. | Secondary X rays |
| D. | All of the above |
| Answer» B. Light emission | |
| 644. |
If the required X ray exposure time for a 225 kV, 5 mA exposure is 3 minutes, approximately what exposure time would be required at 10 mA? |
| A. | 1/2 minute |
| B. | 1 minute |
| C. | 1.5 minutes |
| D. | 3 minutes |
| Answer» C. 1.5 minutes | |
| 645. |
The half-life of Cs-137 is approximately: |
| A. | 74 days |
| B. | 129 days |
| C. | 5.3 years |
| D. | 30.1 years |
| Answer» D. 30.1 years | |
| 646. |
Unacceptable radiographic film quality would be indicated by: |
| A. | Artifacts of known origin in the film's area of interest |
| B. | Use of a smaller penetrameter than required |
| C. | H & D density less than 2.0 |
| D. | All of the above |
| Answer» D. All of the above | |
| 647. |
Which of the following welding discontinuities would be most difficult to image radiographically: |
| A. | Porosity |
| B. | Lack of side wall fusion |
| C. | Undercut |
| D. | Slag inclusions |
| Answer» B. Lack of side wall fusion | |
| 648. |
The most important factor in limiting radiation exposure is: |
| A. | Time |
| B. | Distance |
| C. | Shielding |
| D. | All of the above |
| Answer» D. All of the above | |
| 649. |
The threshold energy below which pair production cannot occur is approximately: |
| A. | 100 keV |
| B. | 1 MeV |
| C. | 10 MeV |
| D. | 20 MeV |
| Answer» B. 1 MeV | |
| 650. |
A photon-electron interaction in which a photon gives up all its energy to an electron is called: |
| A. | The photoelectric effect |
| B. | The Compton effect |
| C. | Pair production |
| D. | Bremsstrahlung |
| Answer» A. The photoelectric effect | |
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