Vocabulary Flashcards
Matter
Has form or shape and occupies space
Mass
Amount of matter in an object; generally considered the same as weight
Energy
Ability to do work
Potential energy
Energy of position
Kinetic energy
Energy of motion
Chemical energy
energy resulting from a chemcial reaction
Thermal energy
Heat energy resulting from movement of atoms or molecules
Nuclear energy
Energy resulting from the nucleus of an atom
Electromagnetic energy
Energy that is emitted and transferred through matter
Ionizing radiation
Electromagnetic radiataion that is able to remove an electron from an atom
Ionization
Removal of an electron from an atom
Measurement Standards
Length
Meter
Measurement Standards
Mass
Kilogram
Measurement Standards
Time
Second
Measurement Standards
MKS System
Meters, Kilogram, second
Measurement Standards
SI System
Meter, Kilogram, and Second
Measurement Standards
CGS System
Centimeter, gram, second
Measurement Standards
British system
Foot, pound, second
Measurement Standards
Velocity (speed)
How fast an object is moving
Measurement Standards
Acceleration
Rate of change of speed per unit of time
Measurement Standards
Work
Force applied on an object over a distance
Measurement Standards
Power
Rate of doing work (measured in watts)
Atomic Structure
Atomic Nucleus
Contains protons (positively charged) and neutrons (no charge); contains most of the mass of an atom
Atomic Structure
Atomic mass
Number of protons plus number of neutrons; represented by the letter A
Atomic Structure
Electron Shells
Contain orbital electrons (- charges); represented by the letters K,L,M,N,O,P, and Q; in a stable atom, the number of electrons and protons is equal
Atomic Structure
Atomic number of an atom
Equals the number of protons in the nucleus; represented by the letter Z; the atomic number determines the chemcial element; all elements are represented in the period table of elements
Atomic Structure
Isotopes
Atoms with the same number of protons but with a different number of neutrons
Atomic Structure
Electron-binding energy
Force that holds electrons in orbit around the nucleus
Atomic Structure
Octet rule
Outer shell of an atom may not contain more than 8 electrons
Atomic Structure
Particulate radiation
Alpha particles(helium nucleus - two protons and two neutrons); Beta particles (electronlike particles emitted from the nucleus of a radioactive atom)
Characteristics of Electromagnetic Radiation
Photon
Smallest amount of any type of electromagnetic radiation; also considered a bundle of energy called a quantum; travels at the speed of light; travels in waves in a straight path
Characteristics of Electromagnetic Radiation
Sine Waves
waves of electromagentic radiation; wave height is called amplitude; distance between peaks of waves is called wavelength; as a photon wavelength decreases, photon energy increases
Characteristics of Electromagnetic Radiation
Frequency
Number of wavelengths passing a given point per unit time; meassured in hertz (Hz)
Characteristics of Electromagnetic Radiation
Speed of Travel
Electromagenetic radiation travels at the speed of light (186,000 miles per second); travels at the speed of light is constant regardless of wavelength or frequency; wavelength and frequency of electromagnetic radiation are inversely proportional
Characteristics of Electromagnetic Radiation
Gamma Rays
Electromagnetic rays produced in the nucleus of radioactive atoms; x-ray and gamma rays differ only in their origins
Characteristics of Electromagnetic Radiation
Wave-particle duality
Concept that although x-ray photons exist as waves, they exhibit properties of particles
Characteristics of Electromagnetic Radiation
Attenuation
Particel absorption of the energy of an x-ray beam as it tranverses an object
Characteristics of Electromagnetic Radiation
Inverse Square Law
Law that governs the intensity of x-radiation; states that the intensity of the x-ray beam is inversely proportional to the square of the distance between the source of the x-rays and the object
Characteristics of Electromagnetic Radiation
Law of conservation of matter
Matter cannot be created or destroyed; only changed in form
Principles of Electricity and Magnetism
Electrostatics
Stationary electrical charges (static electricity)
Principles of Electricity and Magnetism
Electrification
Movement of elctrons between objects
Principles of Electricity and Magnetism
Law of electrostatics
Unlike charges attract, and like charges repel; electrostatic charges reside on the outer surface of a conductor and are concentrtated at the area of greatest curvature; only negative charges move
Principles of Electricity and Magnetism
Methods of electrification
Friction, contact, and induction
Principles of Electricity and Magnetism
Conductor
Material that allows the free flow of electrons
Principles of Electricity and Magnetism
Insulator
Object that prohibits the flow of electrons
Principles of Electricity and Magnetism
Electrical current
Movement of electrons along a conductor or pathway (electrical circuit); measured in amperes
Principles of Electricity and Magnetism
Electromotive force (EMF)
Measured in volts; the force with which electrons move in an electrical circuit
Principles of Electricity and Magnetism
Electrodynamics
electrical charges in motion
Principles of Electricity and Magnetism
Semiconductor
material that may act as an insulator or conductor under different conditions
Principles of Electricity and Magnetism
Electrical resistance
Measured in ohms
Principles of Electricity and Magnetism
Ohm’s Law
Voltage in the circuit is equal to the current x resistance
Principles of Electricity and Magnetism
Electrical circuits
Path along which electrons flow; may be wired as series circuits or parallel circuits
Principles of Electricity and Magnetism
Alternating current (AC)
Electrical circuit in which the current of electrons oscillates back and forth
Principles of Electricity and Magnetism
Direct current (DC)
Unidirectional flow of electrons in an electrical conductor
Principles of Electricity and Magnetism
Sine Wave
Representation of electron flow as alternating current
Principles of Electricity and Magnetism
Magnetic field
Energy field surrounding an electrical charge in motion; can magnetize a ferromagnetic material, such as iron, if the material is placed in the magnetic field
Principles of Electricity and Magnetism
Magnetic Poles
every magnet has a north pole and a south pole
Principles of Electricity and Magnetism
Law of magnetics
Like poles repel, and unlike poles attract; the force of attraction between poles is goverened by the inverse square law
Principles of Electricity and Magnetism
Electromagnetism
Movement of electrons in a conductor produces a magnetic field around the conductor; a coiled conductor (i.e., a wire), through which an electrical current is flowing, as overlapping magnetic fields
Principles of Electricity and Magnetism
Solenoid
Stacks of wired coil through which electrical current flows, creating overlapping force field lines; a magnetic field is concentrated through the center of the coil
Principles of Electricity and Magnetism
Electromagnet
Solenoid with an iron core that concentrates the magnetic field
Principles of Electricity and Magnetism
Electromagnetic induction
process of causing an electrical current to flow in a conductor when it is placed within the magnetic field of anther conductor; two types of electromagnetic induction are self-induction and mutual induction
Principles of Electricity and Magnetism
Self-induction
Opposing voltage created in a conductor by passing alternating current through it
Principles of Electricity and Magnetism
Mutual induction
inducing current flow in a secondary coil by varying the current flow through a primary coil
Principles of Electricity and Magnetism
Electrical generator
Device that converts mechanical energy to electrical energy; usual output of an electical generator is alternating current
Principles of Electricity and Magnetism
Single-phase, two-pulse alternating current
simplest type of current; voltage (and accompaning current) flows as a sine wave; voltage begins at zero, peaks at full value at the crest of the wave, returns to zero, reverses, and again peaks on the inverse portion of the cycle at the trough
Principles of Electricity and Magnetism
Three-phase alternating current
Special wiring patterns (“wye,” “star,” “delta”) used to create voltage waveforms that are placed 120 degrees out of phase with one another; these voltage waveforms are called three-phase; three-phase waveforms may have 6 pulses per cycle or 12 pulses per cycle; three-phase, 6-pulse waveforms contain 360 pulses per second; three-phase 12 pulse waveforms contain 720 pulses per second; high-frequency generators produce high-frequency electricity
Principles of Electricity and Magnetism
Electrical motor
Device that converts electrical energy to mechanical energy
Principles of Electricity and Magnetism
Transformer
Changes electrical vltage and current into higher or lower values; the transformer operates on the principle of mutual induction, so it requires alternating current
Principles of Electricity and Magnetism
Step-up transformer
Transfomer that increases voltage from the primary to the secondary coil and decreases current in the same proportion; a step-up tranformer has more turns in the secondary than in the primary coil; a step-up tranformer is used in the x-ray circuit to increase voltage to the kilovoltage level for x-ray production
Principles of Electricity and Magnetism
Step-down transformer
Transformer that decreases voltage from the primary to the secondary coil and increases current in the same proportion; a step-down transformer has more turns in the primary than in the secondary coil; a step-down transformer is used in the filament portion of the x-ray circuit to increase current flow to the cathode
Principles of Electricity and Magnetism
Autotransformer
Transformer that contains an iron core and a single winding of wire; an autotransformer is used in the x-ray circuit to provide a small increase in voltage before the step-up transformer; the kVp settings are made at the autotransformer
Principles of Electricity and Magnetism
Rectification
Process of changing alternating current to direct current
Principles of Electricity and Magnetism
Line voltage compensation
x-ray circuit depends on a constant source of power; power coming into the radiology department may vary; line voltage compensator keeps incoming voltage adjusted to proper value; usually operates automatically but may be manually adjusted on older equiptment