Lesson 1 - SI Units Flashcards
Name the 3 components in an SI unit
Prefix
Unit symbol
Exponent
What is a vector quantity
A quantity with direction and magnitude
What is a scalar quantity
A quantity with only magnitude
Define force
A movement from a stationary bidy that alters the speed or direction if a moving body
Define work
Energy transferred when a force moves an object
Energy that is usefully sounded
Define power
Rate of doing work or rate of using energy
Joules per second/ watts
Define unit of work
Product of magnitude of the force and the distances moved in the direction of the force
Why are SI units not always convenient
They may be too large or too small
Derived quantities are produced from a combination of SI base units and always contain one of the following three base units:
m, kg, s
how many measurements are in the SI system
7 base units
what is equal to 1mSv
10-6 Sv
what expresses a millionth
micro
is atomic number oir mass bigger
mass. located at the topic with protons and neutrons
What is the name of the band of electron orbitals that electrons can jump up into from the valence band via a process called excitation?
conduction band
Which is a form of electromagnetic ionising radiation?
gamma decay
What type of ionising radiation are X-rays?
electromagnetic
Of what element is the rotating anode disc made?
tungsten
list required characteristics of the filament in an X-Ray machine
-strong metal
low vapour pressure
-low thermionic work function
A continuous X-Ray spectrum is produced by which interactions?
An X-ray photon being absorbed by an electron in an atom is called photoelectric absorption.
An X-ray photon being scattered by an electron in an atom is called Compton scatter.
define attenuation
reduction in energy per unit area of x-ray beam
what has no affect on attenuation
collimation
what is the half value thickness
The thickness of a substance that will transmit 50% of the x-ray photons to which it is exposed
in compton interaction, where can a phoyon be scattered
in any direction
forward
backwards
sideways
What does ‘0.25mm lead equivalent’ mean?
A material attenuates the x-ray beam as much as 0.25mm of lead
What does ‘mAs’ indicate?
Tube charge
