Selected Topics

Question 1

What describes the differences between density of a radiograph?

Answer 1

Contrast

Question 2

Would a long or short wavelength produce a sharper contrast radiograph

Answer 2

long

Question 3

___ occurs when incident x-ray photon is deflected from its original path by an interaction with an electron

Answer 3

compton scattering

Question 4

___ refers to the scattering of electrons and reduces contrast and definition

Answer 4

scatter

Question 5

__ refers to scatter radiation that bounces off an object behind the film then back into the film

Answer 5

backscatter radiation

Question 6

__ describes the fraction of radiation absorbed or scattered per unit thickness of the absorber

Answer 6

linear attenuation coefficient

Question 7

What is the partially shaded outer region of a shadow cast by an opaque object?

Answer 7

Penumbra

Question 8

This type of X-ray produces radiation of composed of a continuous spectrum of energies over some range.

Answer 8

Bremmstrahlung

Question 9

As wavelengths become shorter/longer, penetrating power increases

Answer 9

shorter

Question 10

What 2 factors determine film contrast?

Answer 10

type of film used, process used to develop film

Question 11

Who discovered radioactive materials?

Answer 11

Henri Becquerel

Question 12

The thickness of a material where 50% of incident energy has been attenuated is known as __

Answer 12

half value layer

Question 13

Who discovered the x-ray?

Answer 13

Wilheim Roentgen

Question 14

__ and __ is a form of particle radiation and electomagnetic radiation.

Answer 14

x-rays and gamma rays

Question 15

What happens to penetrating power as radiaion energy increases?

Answer 15

increases

Question 16

A specific radioactive source always produces gamma rays at the same A) Intensity, B) Activity, C) Energy level

Answer 16

C) Energy level

Question 17

Through what two processes is radiation produced in x-ray generators?

Answer 17

Bremsstrahlung, K-Shell

Question 18

__ indicates the amount of attenuation per centimeter.

Answer 18

Linear attenuation coefficient

Question 19

__ is the rate an radioactive isotope becomes stable

Answer 19

Decay Rate

Question 20

What two types of interactions account for the majority of attenuation in industrial radiography?

Answer 20

commpton scattering and photoelectric absorption

Question 21

What is the purpose of using lead foil sheets in radiography?

Answer 21

to increase film density because incident radiation liberates electrons to help expose the film

Question 22

Higher energy radiation has more A) Speed, B) Incident Energy, C)Penetrating Power

Answer 22

C) Penetrating Power

Question 23

What causes undercut?

Answer 23

scattering within the film

Question 24

What is undercut?

Answer 24

loss of resolution at a sharp thickness transition area

Question 25

Why are radiation beam filters used?

Answer 25

to remove low energy radiation to increase definition

Question 26

Where are Image Quality Indicators placed?

Answer 26

on front side of test component, in area of similar thickness to primary area of interest

Question 27

What are the four types of radiation-matter interactions that contribute to total attenuation?

Answer 27

compton scattering, pair production, photoelectric absorption, rayleigh scattering

Question 28

__ x-ray technique allows test component to be viewed in various cross-sectional slices

Answer 28

computed tomography

Question 29

Why is target of x-ray tube often made of tungsten?

Answer 29

It's high atomic mass results in more x-rays generated due to atomic particle interactions.

Question 30

List 3 strengths of radiographic inspection.

Answer 30

not limited to material type, can be used to inspect assembled components, can detect surface and subsurface features

Question 31

What causes attenuation of radiation (2)?

Answer 31

absorbtion, scattering

Question 32

What type of defects are radiography best suited?

Answer 32

volumetric defects such as porosity

Question 33

When should radiography be used for crack detection?

Answer 33

the orientation of the crack is known