Radiography Physics Ch. 3
Physics quizlets.
Terms
undefined, object
copy deck
- semiconductor
- william shockley, materials can act as conductors OR insulators, generally composed of silicon and germanium, transistors
- potential difference
- what makes electrons go forward & back, electric potential, force (strength) with wich electrons travel, also called EMF, measured in volts (V)
- movement
- only negative charges move along SOLID conductors
- superconductor
- electron flow with no resistance, no electric potential required, must be very cold
- electric power
- measured in watts (W), one watt= one amp of current flowing through an electric potential of one volt for one second, power loss is proportional to the square of the amperage in a circuit
- electrification
- the process of electron chargers being added to or subtracted from an object
- are electrons infinately moveable
- yes
- sources of electrical circuit
- batteries, generators, solar converters, atomic reactors
- electrostatics
- study of the distribution of fixed charges
- negative electrification
- electrons have been added to an object, giving it a net negative charge
- friction
- rubbing one object against another, especially during times of low humidity
- electrodynamics
- the study of electric charges in motions: electricity
- series cicuit
- all circuit elements are connected in a line along the same conductor, electric circuit with the components arranged to provide a single conducting path for current, adding current using devices will cause voltage to drop, any devices in a series circuit that does not work causes the entire circuit to fail
- What conditions cause electrification
- friction, contact, induction
- ohm's law
- voltage across the total circuit or any portion of the circuit is equal to the current times the resistance (V=iR)
- uncharged particles
- exert no force, and are not acted on by charged particles
- current flow
- electrons move from the highest concentration to the lowest
- electrification b
- when an object is made to have a insufficiency or excess off electrons
- distribution
- solid conductors have the excess electrons spread over thier outer surface
- are voltage and amperage inversly proportional
- yes
- electrical circuit
- require a close path (if open consider non-working), potential difference must exist for electrons to flow
- positive electrification
- electrons have been removed from an object, leaving it with a net positive charge
- electric resistance
- the amount of opposition to the flow of electrons
- circuit breaker
- too much amperage will cause pop
- rheostat
- potentiometer, variable control of amperage, increased resistance allows less current to go to device
- contact
- equalization of charges, static discharge
- parallel circuit
- total resistance is always lower than lowest resistor, circuit elements will bridge the conductor, 2 or more components are connected across 2 common points (bridge) in the circuit to provide seperate conducting paths for current, adding resistors increases amperage & heat
- electric resistance influcenced by
- cross-sectional area of the conductor, temperature of the conductor (higher tem=high resistance), length of the wire (longer=higer resistance), increasing resistance decreases electric current
- example of induction
- balloon vs. wall, high electron balloon causes electrons in wall to disperse in that area
- induction
- electrical fields acting on one another without contact
- laws of elecrostatic force
- force, colomb's law, distribution, concentration, movement
- insulator
- substances that inhibit the flow of electrons, insulators will confine the electron flow to the conductor
- is the earth an electric ground
- yes
- alternating current
- when electrons first move in one direction and then reverse and move in the opposite direction
- conductor
- any substance along which electrons flow easily, good heat conductors are generally good electrical conductors
- fuse
- too much amperage will melt
- concentration
- electric charges will be concentrated along the sharpest curvature of the conductor
- attraction
- unlike charges attract
- types of circuit devices
- circuit breakers, fuses, rheostat (potentiometer)
- qualities of electric resistance
- may be called impedance, measured in ohms.
- electric resistance material
- elements with one electron in the valence shell conduct electricity well, the further the valence shell is from the nucleus (higher shell #) the more efficiently it conducts electricity, conduction band (higher conductivity=less resistance)
- coulomb
- the fundamental unit of electric charge
- current
- the quantity of electrons flowing, measured in amps (I) (A), may indicate the presence of electron flow
- repulsion
- like charges repel
- direct current
- when all electrons move in the same direction or pulsating
- coulomb's law
- inverse square law
- ionic solutions
- neutral atoms with complimentary valences (+1 and -1) are placed in a solution, charged atoms move toward oppositely charged poles