Theory Flashcards
Term given for time take for milky appearance to disappear when processing
Clearing time
Which things may help to reduce diffraction mottling
Lead screens, off setting the beam and higher kv
Another term used to describe parallex technique
Tube shift method
Penumbra is correct term for ?
Geometric unsharpness
Why is a duplex iqi used
Indicate definition
When using x rays whys a filter used
To remove low energy radiation
Which will affect inherent unsharpness
Kv
The law of reciprocity links exposure in ma and…
Time
If fluorescent screens were used instead of lead what effect would this have
Decreased expose and decreased definition
Lead screens are often used above 120kv why?
To intensify the beam by emitting electrons
Filters used in the primary beam from an x ray set have what effect?
Increase the average energy and decrease contrast
In electric arc welding a metal rod is one electrode the other is?
The work material
Which could occur in parent plate because of welding?
Lamella tear + haz crack
Where gas is used as a shield for the welding process the gas is commonly?
Argon helium and hydrogen
Which welding process takes place in a vaccum ?
Electron beam welding
When welding thin plate material which process would be used
Tig or mig
In regard to atomic number which will be larger
Mass number
A change in the number of protons in an atoms nucleus will result in
The atom becoming a different element
What are the 3 main forms of attenuation in regards to x and y radiation
Photoelectic effect, pair production and compton effect
The term bremsstrahlung refers to
The primary radiation produced by slowing of a high speed electron bu the positive field around the nucleus of an atom
Describe beta decay
A neutron in the nucleus breaks into a proton and an electron the electron is emitted from the nucleus
What maintains the structure of an aton
Binding energy
Atoms and sub atomic atoms carrying either a positive or negative charge are called
Ions
Film contrast is affected by what?
Film speed
The intensity of x rays produced is governed by ?
The current applied to the cathode
The atomic number of an atom is the number of
Protons
For an atom to be electrically neutral there must be an equal number of protons and ???
Electrons
What has a half life of 74 days
Iridium 192
Energy of an x ray set is measured in?
Kv or mv
Which word describes the clarity or sharpness or image
Definition
SI unit for activity ?
Becquerels
A small focal spot will ?
Reduce geometric unsharpness
Radiation is measured in ?
Mev or kev
