Module 12 Flashcards
Definition- heat transfer involving electromagnetic waves
Radiation
All objects emit energy via _____
Radiation
_______ _____ are produced when charged particles are accelerated
Electromagnetic waves
Electromagnetic waves are composed of….
Mutually perpendicular electric and magnetic fields
________ ______ have properties of both waves and particles but are neither waves nor particles
Electromagnetic waves
At what speed do all electromagnetic waves move at the same speed through a vacuum?
(C) the speed of light (3.00x10^8 m/s)
C= the speed of light=
3x10^8 m/s
Wavelength;
Distance required for wave to repeat itself (meters), distance between peaks and troughs
Period (T):
Time required for a wave to repeat itself (seconds)
Frequency (f):
Number of wave cycles that occur in 1 second (Hz)
This determines the energy of radiation, and therefore the potential for cellular damage
Frequency
Velocity
(Meters/second)
Name the four electromagnetic wave properties
Wavelength (m), period (s), frequency (hz), velocity (m/s)
Frequency & wavelength are ______ proportional
Inversely
Increased frequency = _________ wavelength
Shorter
Increased frequency = ________radiation
Increased
Decreased frequency = _________ wavelength
Longer
Decreased frequency= ________ radiation
Lower
Law of energy conservation (equation)
E=mc^2
Law of energy conservation
Amount of energy In the universe if constant, cannot be created or destroyed, but can be converted (ie from matter to energy and vice versa)
Atomic mass number (A):
An integer equal to the number of protons plus the number of neutrons in the nucleus
Atomic number
Number of protons. Determines the element
Nucleon
Describes both neutrons & protons in the nucleus (atomic particles)
This is the general description of an atom- defined by atomic number, number of neutrons, and energy state of the nucleus
NUCLIDE
Isotope
Nuclides with same Z but with different N and A.
Identical electron configuration with similar chemical properties
Isotone
Nuclides with the same number N but different Z.
Different element with different chemical properties
Radionuclides
Nuclides that decay
Most Nuclides are ______ stable and _____ by splitting apart
Not
Decay
Nuclides emit ________ and/or _________ ________
Subatomic particles
Electromagnetic radiation
When ______ forces exceed ______ forces, the nucleus is unstable leading to _______ ________.
Repulsive
Attractive
Radioactive decay
Nucleus must balance _______ & _______ forces
Attractive
Repulsive
Repulsive forces=
Protons that repel each other
Strong nuclear force binds ______ together
Nucleons
Attractive nuclear force only successful over ________ distances
Very short distances
So short they are almost in contact
Radionuclides:
Nuclides that decay
Radioactive decay;______ process of an ____ nucleus moving from a level of _______ energy to one of ______ energy
Spontaneous
Unstable
Higher
Lower
Radioactive is decay achieved by several means ; list 3
Fragmentation (fission)
Emission Of subatomic particles
Emission of electromagnetic radiation
5 types of decay (in this lecture)
Alpha Beta (-) Positron Electron capture Gamma ray
Alpha decay
Emission of alpha particles by parent nucleus

Beta (-) decay
Radioactive decay process in which the nucleus emits an electron
Positron decay
1 anti- electron (+ charge but same mass as an electron) is decayed
A proton turns into a neutron and releases a positively charged positron
Positron
Anti-particle of electron
Basic example of antimatter
(Identical mass but opposite charge of corresponding particle)
Electron capture decay
A competing process to positron decay, results in an increase in neutron to proton ratio in the nucleus. (A nucleus in an excited state can D excite and emit a photon of electromagnetic radiation called a gamma ray)
An electron turns a proton into a neutron
Official SI unit of decay rate
Becquerel (Bq)
Decay rate is equal to the # of ______ __________ per unit time
Radioactive decay/disintegration
Historical unit of decay, much larger than (Bq), still in use today
Curie (Ci)
Decay rate depends on two factors-
Quantity of material
Decay constant, which is unique to each nucleotide
______-______ (t 1/2) is a measurement tool for radioactive decay
Half-life
Half life (t 1/2) is defined as ….
The time required for an initial number of atoms to decay such that only half of the initial number of atoms remain
Relationship between Half life and decay constant
t 1/2 X ¥ = 0.693
Why do we need half life measurements?
Because the decay of a single radio nuclide in a large collection of atoms is not readily predictable and can have enormous variation
Name the three types of radioactive materials
Primordial radionuclides
Cosmogenic radionuclides
Anthropogenic radionuclides
Primordial radionuclides…
Exist since the earliest times of earth and solar system
Very long half lives
Ex EXCELLENT time measurement tools due to known half lives and decay properties
Cosmogenic radionuclides
Formed when radiation from space interacts with matter
Ex Carbon dating 
Anthropogenic radionuclides
Occur in the environment as a result of human activity
Ex. Nuclear medicine, electricity generated by nuclear power stations, nuclear weapons testing
What type of radioactive material uses of carbon dating
Cosmogenic radionuclides
This type of radioactive material is excellent time measurement tool due to its known half life and decay properties
Primordial radionuclides
Examples of this radioactive material are nuclear medicine and electricity generated by nuclear power stations and nuclear weapons testing
Anthropogenic radionuclides
Low energy photons can be absorbed by matter resulting in an increase in internal energy
Non-ionizing radiation
Examples of non-ionizing radiation
Microwave, infrared, visible and ultraviolet
This type of radiation is defined by its lack of sufficient energy to remove electrons so no ions are formed
Non-ionizing radiation
Harmful effects of UV radiation
Skin cancer and cataracts
Definition: Sufficient energy per photon or particle to remove electrons from atoms or molecules
Ionizing radiation
What type of radiation is most destructive and can result in Cell DNA damage, chromosome changes, and/or malignant growth
Ionizing radiation
Alpha particles, beta particles, gamma rays, x-rays
Ionizing radiation (aka all have sufficient energy per photon or particle to remove electrons from atoms or molecules)
High energy photons released from electron transitions involving the innermost or core electrons
X rays
High energy photons produced from transition of electrons from higher quantum energy level to a lower quantum energy level
Gamma rays
Law of Bergonie & Tribondeau
Different types of cells display varying sensitivity to ionizing radiation
What 3 factors affect radiation on biological system
Type of radiation
Exposure level
Type of biological material
Definition: Biological effects due to radiation exposure ranging from repairable damage, permanent damage, up to cell death
Somatic effects
Definition: Cell damage involved with reproduction can result a mutation Passed on to future generations
Genetic effects
Products of radiation interaction with the water inside our bodies (majority of cell)
Ions, free radicals, atoms and molecules in excited states
Two types of cells that are most sensitive to radiation…
Rapidly dividing cells (gonads, fetus, lens of eye) AND cells that are not replaced (ovaries, cns)
Both exhibit enhanced sensitivity to radiations
