McqMate
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 | |
| 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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