Radiotion Physics CH1-4 Flashcards
Physics
Relationship between energy, matter and force interations.
Radiological Physics
Study of nature and origin of x rays.
Medical Physics
Application of physics to medicine ex medical imaging and radiotherapy
___Created atomic structure we still use.
Bohr
7 Units of measurement
Length, mass, time, area, volume, velocity, temp
Mega
1,000,000
Kilo
1000
Hecto
100
Deca
10
Base
0
Deci
0.1
Centi
0.01
Milli
0.001
MKS System
M=Meter(length), K=Kilogram(mass), S=Seconds(time)
Atom
smallest particle into which matter can be divided while still maintain its unique properties.
Atom Particles
Protons, Neutrons, Electrons.
Atomic # (z)
of protons
Atomic Mass #
protons and Neutrons combined
Basic structures of matter
Chemical element, Molecules, Compound, Isotopes.
Hydrogen’s isotope?
Deuterium
Matter comes in 3 forms:
Solids, liquids, gas
Valence Shell
Outer shell of an atom, it determines chemical reactivity and the # of electrons determines position on the table.
Rule of Octect
Outer shell will hold up to 8 electrons.
Electron Volt
The binding energy of an electron is measured in eV.
1 keV is equal to
1000 electron volts
Can only occupy the shells of energy designated by different letters of the alphabet:
Electrons
Occupancy Factor
2n^2
Valence #
of electrons in a valence
KLMNOPQ
1234567
Ionized
an atom loses of gains an electron
Ionization
process of + or - electrons
Cation
electron removed more positive
Anion
an added electron becomes more negative
Ion
Charged atom
A body at rest or in uniform motion nremains in the same state unless force is applied
Newtons 1st law of motion
Force
Push or pull of an object.
What is the unit of force?
Newton
What is the unit for electromotive force?
Volatge
Mechanical energy 2 types:
Potential and Kinetic
Potential energy
stored energy/inertia
Kinetic energy
energy in motion
Definition of energy
the ability to do work
Work
application of force over distance
Force x Distance =
Work
Unit used for energy is?
joule (j) or erg
Energy emitted and transferred through matter is called:
Radiation
Chemical Energy
Is released through chemical changes in the atoms and or molecules.
Thermal energy
aka heat results of atoms in motion.
Nuclear energy
energy released from radionuclides.
Different types of energy?
Mechanical, Chemical, Thermal, and Nuclear
Law of Conservation
Energy can neither be created nor destroyed, but changed into other forms of energy.
Laws of electricity
Unlike charges attract and like repel, only neg charges move in a conductor, electric charges reside on conductor surface.
Electrification
Results from deficiency or excess amount of electrons that move from one object to another.
Elecricity
Flow of electrons around a ciruit.
DC current:
Electrons move in the same way.
AC current:
move in rythe from + to -
AC current: Pulse
a change in polarity
AC current: Cycle
2 pulses
AC current: frequency
of cycles
Current (I):
flow of electrons
Amperes (A)
measurement for current,
Electromotive Force (EMF)
Force pushing electrons
Volts (V)
measurement for EMF
Circuits:
Flow from pos to neg
Resistance (R)
Using or resisting energy, measured in ohm.
OHM’s Law
V=IR, is the basic principle of all circuits.
Watt (W)
unit for electrical power, work over a given amount of time. W=AxV
Ampsxvolts
OHM
amount of resistance overcome by one volt to cause one amp to flow
Electical charges are measured in:
Coulombs C
Electical charges flow from:
neg to pos
Electical charges are affected by
Conducting material, conductor length, diameter of conducting material, and conductor temp.
Magnetism:
ability of a substance to attract iron or iron like substances
Electomagnetism:
an electric current will always produce a magnetic field.
Magnetic field is created by:
electric current passing through wire.
Cause for a weaker magnetic field:
Straight wire, when wire is wrapped around a core of wire strength increases.
Self induction
AKA autotransformer; created its own magnetic field.
Electomagnetic:
Materials strongly attracted to magnet or Ferromagnetic
Materials weakly attracted are:
Paramagnetic
Materials not attracted are:
Diamagnetic
Radiation:
energy traveling through space.
Non-ionizing radiation:
waves composed of oscillating electric and magnetic fields traveling at speed of light.
Ionizing Radiation:
any magnetic or particulate radiation capable of causing bio harm.
2 ionizing types:
Particulate and electromagnetic; they are mainly xrays and gama with a potential to cause harm
Particulate:
Subatomic particles with mass (alpha and beta)
Frquency:
Cycles per second
Amplitude:
height from peak to valley
Wavelength:
Distance from one crest to the next.
Trough:
dip low point on a wavelength
Photons:
bundle of electromagnetic radiation
X-rays in a diagnostic tube are:
Polyenergetic, heterogenous, polychromatic
3 spectrum quantities:
energy, frequency and wavelength
The longer the wavelength the ____ the ____ and less energy; therefore non-ionizing.
Shorter amplitude
Speed of light:
186,000 miles per second
Xrays travel at:
speed of light
Inverse relationship
As the intensity behind the wave of energy increases the wavelength of energy decreases.
Brems (aka Characteristic)
Breaking radiation, when sudden deceleration of electrons cause it to release all or some of its energy & forms radiation. Requires source and target.
Alpha
low energy easily shielded, cannot penetrate skin and paper.
Beta
high speed electrons ejected from nucleus, potentiall to lose energy in from of x rays upon rapid deceleration. (Brems radiation)
x-rays
photons emitted from electron orbit, when an excited orbital electron “falls” back to lower energy level.
Gamma
photon emitted from nucleus, often part of radioactive decay. Higher energy.
Diodes are normally made of:
silicone
Inverse square law
I1/I2=D1^2/D2^2
