CRI Radiographic Film Interpretation 3 — Questions and Answers
Question 1: On a radiograph, burn-through in a weld is identified by:
- A light (bright) irregular area at the weld root
- A very dark, rounded or irregular area at the weld center (Correct answer)
- A linear dark indication at the weld toe
- A series of equally spaced dark spots
Correct answer: A very dark, rounded or irregular area at the weld center
Burn-through appears as a very dark area because the excess melt-through creates a void or depression with less material to absorb radiation.
Question 2: Geometric unsharpness (Ug) in radiography is reduced by:
- Increasing source size and decreasing SFD
- Decreasing source size and increasing SFD (Correct answer)
- Increasing kV and decreasing mA
- Using faster film and reducing exposure time
Correct answer: Decreasing source size and increasing SFD
Geometric unsharpness decreases with a smaller source size and a greater source-to-film distance, producing a sharper image.
Question 3: Which type of radiation scatter most degrades radiographic image quality?
- Primary radiation
- Back scatter (Correct answer)
- Side scatter
- Coherent scatter
Correct answer: Back scatter
Back scatter, originating from material behind the film, strikes the film from the film side and can significantly fog and degrade image quality.
Question 4: The radiographic image of an elongated slag inclusion typically appears as:
- A rounded dark spot
- An irregular dark linear or elongated indication (Correct answer)
- A light rectangular area
- A series of dark parallel lines
Correct answer: An irregular dark linear or elongated indication
Slag inclusions, being less dense than weld metal, appear as irregular dark elongated indications on the radiograph.
Question 5: When the required wire of an IQI is visible on a radiograph, it indicates that:
- The exposure is overdue for recalibration
- The required level of radiographic sensitivity has been achieved (Correct answer)
- The film density is too high
- Scattered radiation is excessive
Correct answer: The required level of radiographic sensitivity has been achieved
Visibility of the designated IQI wire confirms that the radiograph meets the required sensitivity specified by the applicable code or standard.
Question 6: An 'arc strike' on base metal adjacent to a weld would appear on a radiograph as:
- A dark rounded spot outside the weld zone (Correct answer)
- A bright linear indication within the weld
- No indication, because arc strikes don't affect radiograph appearance
- A dark elongated line running through the weld center
Correct answer: A dark rounded spot outside the weld zone
Arc strikes appear as small dark rounded areas on the base metal outside the weld because local melting creates a thinner or altered zone.
Question 7: The primary purpose of using lead intensifying screens in industrial radiography is to:
- Increase image sharpness by filtering low-energy radiation
- Reduce exposure time by emitting electrons that expose the film (Correct answer)
- Increase kV to penetrate thicker sections
- Eliminate back scatter from the cassette back
Correct answer: Reduce exposure time by emitting electrons that expose the film
Lead screens emit secondary electrons when struck by X-rays or gamma rays, which help expose the film and allow shorter exposure times.
CRI Radiographic Film Interpretation 3
On a radiograph, burn-through in a weld is identified by: