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Physics- Units 2-4
| Question | Answer |
|---|---|
| Length is measured in _________. | meters |
| Mass is measured in _______________. | kilograms |
| Time is measured in _____________. | seconds |
| Temperature can be measured what 3 ways? | Fahrenheit, Celsius, and Kelvin |
| Mass of an object compared to its volume is _______________. | density so, D= mass/volume |
| The rate of change in position with regard to time is ______________. | velocity so, V= distance/time |
| All matter is composed of ______________. | elements |
| What makes an element distinguishable from all others? | by the chemical and physical properties of its most basic component, the atom |
| How many elements are on the periodic table? | 118 |
| 1-94 on the periodic table are _____________ occurring. | naturally |
| 95-118 on the period table are _______________ elements. | synthetic (man-made) |
| On the periodic table, the columns going from top to bottom are called __________. | groups |
| On the periodic table, the rows stretching across are called ___________. | periods |
| There are ___ groups and ____ periods. | 18;7 |
| The groups indicate what? | the number of electrons in the outermost shell |
| The periods indicate what? | the number of electron shells (number of energy levels) |
| Atomic number = ___________ | # of protons |
| Atomic mass = ___________________________ | # of protons and neutrons |
| What does the atomic number determine? | the chemical properties of the element and its place on the periodic table |
| Atomic mass is given in terms of ______. | amu |
| Proton amu | 1.00728 |
| Neutron amu | 1.00867 |
| What does electron arrangement determine? | how the atom will interact |
| Electron amu | .000549 |
| The atom is electrically _____________. | neutral |
| Atomic nomenclature is used to represent ______________. | nuclides |
| With the atomic nomenclature, what do A, X, and Z represent? | A= the atomic mass X= chemical symbol Z= atomic number |
| The same number of protons | isotopes |
| Different number of protons, but same number of neutrons. | isotones |
| Different number of protons and neutrons, but same atomic mass | isobars |
| Same atomic mass number and atomic number | isomers |
| Isomers are identical except for the fact that....? | they exist at different energy states due to differences in nucleon arrangement |
| What causes the electrons to orbit the nucleus in shells? | force of attraction |
| Electrons fill each shell based on what? | principle quantum number (2n^2) |
| The outer shell of an atom can never contain more than how many electrons? | 8 |
| Outer shell electrons are also known as ____________ electrons. | valence |
| ____________ ___________ is the force between the nucleus and the orbiting electrons. | binding energy |
| When enough energy is used to overcome the binding energy, the atom becomes ______________. | ionized |
| The electron binding energy is expressed in terms of __________ _________. | electron volts (eV) |
| KeV= ___________ times an eV | 1000 |
| Short-range force hadron force (protons and neutrons) | strong force |
| This is responsible for binding the electrons and the nucleus to form the atom and binding atoms and molecules to form solids and liquids | electromagnetic force |
| T or F. Electromagnetic force has an infinite range. | True |
| Short-range force of elementary particles; associated with beta decay. | weak force |
| A strong attractive force between nucleons in the atomic nucleus that holds the nucleus together. | nuclear force |
| Substances formed by chemically combining 2 or more elements. | compounds |
| Substances formed by physically mixing 2 or more substances. | mixtures |
| What is radiation? | the emission of energy as electromagnetic wave or as moving subatomic particles that cause ionization. |
| Electromagnetic radiation is a combination of electrical and magnetic waves which travel at ________ degree angles. | 90 |
| X and gamma rays are also known as _____________. | photons |
| Do photons have mass and charge? | No |
| Are photons affected by gravitational, electrical, or magnetic fields? | No |
| How do photons travel? | in straight lines at the speed of light |
| Can photons be focused? | No, bc of divergence |
| Are photons attenuated by matter? | Yes |
| How far can photons travel in air and tissue? | air: 0-100 cm tissue: 0-30cm |
| Speed of light = | 3x10^8 m/s |
| The only difference between x and gamma rays is their __________. | origin |
| In what fashion do electromagnetic waves travel? | sinusoidal fashion |
| The distance from one crest to another | wavelength |
| Wavelength is represented by | lambda |
| The rate of rise and fall of a wave | frequency |
| Unit of measurement for frequency | Hz |
| Wavelength and frequency are _______________ proportional. | inversely |
| As wavelength becomes shorter, photon energy ____________. | increases |
| As frequency increases, photon energy _____________. | increases |
| Distance from the point of origin to a peak | amplitude |
| What determines energy/intensity of an EM wave? | amplitude |
| X and gamme rays are considered what type of radiation? | non-particulate |
| Particulate radiation is emitted from the _________. | nucleus |
| T or F. Particulate radiation can have a positive, negative, or neutral charge. | True |
| Alpha particle is from a __________ nucleus. | helium |
| Average energy of an alpha particle. | 4-7 MeV |
| Beta particles are ____________ emitted from the __________ during radioactive decay. | electrons; nucleus |
| When does radioactive decay occur? | when the ratio of neutrons to protons in the nucleus is too high; an excess neutrons transforms into a proton and an electron; the proton stays in the nucleus and the electrons is ejected energetically |
| Average energy of a beta particle. | 0-7 MeV |
| Neutron atomic mass number. | 1 |
| Alpha particle atomic mass number. | 4 |
| Beta particle atomic mass number. | 0 |
| Average energy of a neutron. | 2 MeV |
| Proton atomic mass number. | 1 |
| Radioactivity | release of energy via decay of unstable atoms |
| Half-Life | the time for a radioactive source to reduce to one half of its original intensity |
| The total amount of mass and energy in the universe is constant. | The Law of Conservation of Mass-Energy E=mc^2 |
| Stored energy or energy of position | potential energy |
| Energy of motion | kinetic energy |
| Branch of physics that studies slow-moving or stationary electrical charges. | electrostatics |
| Unit of charge for electrostatics is | coloumb |
| 1 Ci = ? Bq | 3.7x10^10 |
| 1 Bq = ? Ci | 2.7x10^-11 |
| 1 Bq = ? dps | 1 |
| 1 Ci = ? dps | 3.73x10^10 |
| What percent of radioactivity is natural and manmade? | natural= 88% manmade= 12% |
| Can particulate radiation be deflected by a magnetic field? | Yes |
| Can electromagnetic radiation be deflected by a magnetic field? | No |
| Gamma rays have a ____________ origin and xrays have a __________ origin. | nuclear; orbital |
| What material stops alpha particles? | paper |
| What material stops beta particles? | plastic |
| What material stops gamma and xrays? | lead |
| What material stops neutrons? | concrete |
| The rate of decay of a radioactive material. | activity |
| T1/2 = | .693/lambda |
| Lambda = | .693/T1/2 |
| The average lifetime for the decay of radioactive atoms | mean life |
| The higher the specific activity, the more __________ __________ you can "pack" into a smaller space. | radioactive material |
| All elements with an atomic number greater than ______ are considered radioactive. | 82 |
| As the number of particles increases, the chance of particle emission ___________ since the effectiveness of forces holding particles together decreases. | increases |
| Uranium series: U-238 decays down to? | Pb-206 |
| Actinum series: U-235 decays down to? | Pb-207 |
| Thorium series: Th-232 decays down to? | Pb-208 |
| The uranium, actinum, and thorium series all end where? | at a stable form of lead |
| When is radioactive equilibrium reached? | when the ratio of daughter activity to parent activity is constant |
| T or F. The apparent decay rate of the daughter nuclide is governed by the decay rate of the parent nuclide. | True |
| What are the 2 types of radioactive equilibrium? | transient and secular |
| Transient equilibrium | **growth in and then decays with parent nuclide ex. 99Mo generator |
| Secular equilibrium | **growth in and remains constant ex. radium needles |
| In alpha particle decay, how many protons and neutrons are emitted? | 2 protons and 2 neutrons which means Z (atomic number) is decreased by 2 and A (atomic mass) is decreased by 4 |
| What is ejected in beta particle decay? | - or + electron |
| B- is called a | negatron |
| B+ is called a | positron |
| - u is known as? | antineutrino |
| For radionuclides with high neutrons/protons ratio, the beta particle tends to be? | B- (negatron) |
| V=? | neutrino |
| Q=? | disintegration energy |
| For radionuclides with low neutrons/protons ratio, the beta particles tend to be? | B+ (positron) |
| What is created with B+ decay? | the positron will combine with another electron and produces annihilation radiation |
| What is detected by a PET scan? | annihilation radiation from positron emission |
| Annihilation results in what? | conversion of 2 electron masses into energy (2 y-ray photons) |
| Electron capture happens when? | an orbital electron is captured by the nucleus and changes a proton into a neutron |
| After electron capture, what is emitted? | a y-ray photon |
| What shell does electron capture mostly involve? | k-shell |
| What happens with internal conversion of radioactive decay? | excess nuclear energy is transferred to an orbital electron which is then ejected |
| Both electron capture and internal conversion result in what? | characteristic x-rays/auger electrons |
| Isomeric transition (IT) radioactive decay | excited state persists for a measurable amount of time and is "metastable" |
| A "metastable" nucleus is an isomer of the final product meaning same atomic number and mass but different ___________. | energy |
| Nuclear reaction of alpha particles and neutrons. | bombardment by alpha particles w/ emission of neutrons |
| Nuclear reaction of proton bombardment | proton is captured by nucleus w/ emission of y-ray |
| Nuclear reaction of deuteron bombardment | **deuteron is a combo of neutrons and protons** either a neutron or proton is emitted after bombardment |
| Nuclear reaction of neutron bombardment | neutrons being neutral in charge can penetrate nucleus and produce nuclear reactions |
| Nuclear reaction of neutron capture | capture of a neutron and y-ray emission |
| Photodisintegration | increased energy of photon interacts with atomic nucleus and mostly results in neutron emission |
| Fission nuclear reactions are useful for what? | power reactors and weapons |
| The way of writing/showing the decay process(es) of a radionuclide | decay scheme |
| What typically is shown on decay schemes? | - radionuclide at start along with intermediate nuclides all the way down to end product (stable) - the type of decay process(es) associated with each level of decay -the 1/2 life of each nuclide -the energies associated w/ each decay process |
| Xrays discovered by ____________ in ______. | Roentgen in 1895 |
| Tube voltage is responsible for what 3 things? | -electron acceleration -electron energy -penetration into tissue |
| Tube current is responsible for what 3 things? | -number of electrons -beam intensity -mu setting |
| What is the target material of anode? | copper w/ tungsten |
| Most modern day tubes are based on what design? | coolidge xray tube |
| What is the purpose of oil bath in the tube? | to reduce heat on target and insulate tube from increased voltage and prevent arcing |
| We want the FSS as _________ as possible to give the sharpest images. | small |
| Smaller focal spots get ____________ heat per unit area of target | increased |
| Use __________ _________ to decrease the FSS. | angled anode |
| This is the variation in xray beam due to greater attenuation of xrays from higher depths within target vs. surface origin. | heel effect |
| Due to heel effect, intensity of xray beam _____________ from cathode to anode direction. | decreases |
| What material is the filament? | tungsten |
| The filament is ___________ charged, and the anode is _____________ charged. | negatively;positively |
| What directs the electrons to the anode? | focusing cup |
| Which circuit gives accelerating potential to electrons? | step up voltage |
| Which circuit gives heating current to filament? | step down voltage |
| Filament temp/current controls what? | tube current and thus xray intensity |
| Braking radiation | bremsstrahlung |
| What happens during brems? | 1. radiative collision btwn high speed e- and nucleus 2. e- is deflected and accelerated 3. get electromagnetic radiation 4. energy of photon is equal to or greater than e- 5. direction of photons depends on electron energy |
| Due to brems, what target is used in therapy? | "xmission target" electrons hit target from one side and get xrays out the other side |
| Y-rays are of nuclear origin have discrete energies and are _________________. | homogenous |
| What kind of filter is used in orthovoltage therapy? | thoraeus filter |
| Thoraeus contains what 3 elements? | tin-copper-aluminum |
| Tin absorbs __________ photons from target. | decreased |
| Cu absorbs ________ photons missed by or created in Tin. | decreased |
| Al absorbs photons created in _______. | Cu |
| Megavoltage therapy uses what type of targets? | xmission targets |
| What is the purpose of flattening filter? | produce a flat beam |
Created by:
lheard
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