CRI Contrast & Exposure Parameters 3

Question 1

The inverse square law in radiography states that radiation intensity varies:

Accepted Answer

Inversely with the square of the distance

Answer

The inverse square law states that intensity is proportional to 1/d², so doubling the distance reduces intensity to one-quarter.

Question 2

In industrial radiography, what is the primary purpose of using lead screens with X-ray film?

Accepted Answer

To filter scatter radiation and intensify the direct beam effect

Answer

Lead screens absorb scatter radiation (improving contrast) and emit photoelectrons that intensify the film's response to the primary beam.

Question 3

A radiograph of a weld shows an image that is overall too dark (overexposed). To correct this while maintaining the same geometry, the interpreter would recommend:

Accepted Answer

Decreasing mAs or increasing SFD

Answer

Reducing mAs decreases the number of X-ray photons reaching the film, and increasing SFD reduces intensity per the inverse square law, both lightening the radiograph.

Question 4

In computed radiography (CR), the exposure indicator value primarily reflects:

Accepted Answer

The amount of radiation that exposed the imaging plate

Answer

The exposure indicator (EI) in CR systems is a measure of the radiation exposure received by the imaging plate, used to assess if exposure was adequate.

Question 5

Which of the following conditions would most reduce radiographic contrast in a steel weldment?

Accepted Answer

Using high kVp with a fast, coarse-grain film

Answer

High kVp reduces differential absorption (lowering subject contrast), and coarse-grain film has lower inherent contrast, both combining to reduce overall radiographic contrast.

(CRI) Certified Radiographic Interpreter Practice Test

(CRI) Certified Radiographic Interpreter Practice Test

CRI Contrast & Exposure Parameters 3