EXAM #8 — PHYSICS UNIT 01 Flashcards
define: electricity (electric current).
electrons moving in a conductor
define: ampere.
unit measure of current flow
define: electric field.
continuous lines of force that radiate from a positive to negative charge
define: electrical potential energy (electromotive force or EMF).
the potential energy created by the attractive or repulsive forces of electric charges
define: impedance.
the conversion of electricity to another form of energy in a circuit
define: resistance.
the type of impedance wherein electricity is converted to heat
define: capacitance.
the type of impedance wherein electricity is converted to an electric field
define: direct current (DC).
current that flows in only one direction in a circuit
define: alternating current (AC).
current that alternates between both directions of flow in a circuit
define: magnetic field.
continuous lines of force that radiate from the north pole of a magnet to the south pole
define: electrodynamics.
the study of moving electrical charges
define: electromagnet.
a conductor that is wound many times and carries an electric current, which creates a magnetic field
define: magnetic domain.
the smallest unit of magnetism
define: magnetic susceptibility.
the degree to which an object is affected by a magnetic field
define: Tesla.
a standard unit of measure for magnetic field strength
define: Gauss.
a standard unit of measure for magnetic field strength
define: phase.
the degree to which waveforms cross a center point in the same direction at the same time or the distance in degrees between the angles of the waveforms
define: electromagnetic induction.
the transfer of energy between electrical and magnetic fields- specifically the ability of a moving magnetic field to induce an electrical current in a circuit
define: electromagnetic radiation.
electric and magnetic fields oscillating perpendicular to and 90° out of phase with each other
describe how distance affects the strength of interaction between electrostatic charges.
inversely square; as the distance between the charges doubles, the strength of the interaction is divided by four
state Ohm’s law and/or express it as a formula.
V=IR
describe and distinguish between an insulator, conductor, semiconductor, and superconductor.
insulators resist electric current;
conductors carry current with impedance;
semiconductors can be made to carry or resist current;
superconductors carry current with little or no impedance
describe and distinguish between ferromagnetism, paramagnetism, and diamagnetism.
ferromagnetism means objects are highly susceptible to magnetic fields;
paramagnetism means they are slightly susceptible;
diamagnetism means they are not susceptible or slightly negatively susceptible
describe and distinguish between temporary and permanent magnets.
temporary magnets lose their magnetism when they are not near an external magnetic field,
permanent magnets retain their magnetism when not near an external magnetic field
describe how like and unlike magnetic poles interact.
like poles repel, unlike poles attract
describe how distance affects magnetic field strength.
inversely square; as the distance from the field doubles, the strength is divided by four
compare the two standards of measure for magnetic field strength.
1 Tesla = 10,000 Gauss
state Faraday’s Law of Electromagnetic Induction.
a changing magnetic field can induce a current in a conductor.
identify the 3 types of impedance.
resistance, capacitance, inductance
identify the physical cause of electromagnetic radiation.
electric and magnetic fields oscillating perpendicular to and 90 ° out of phase with each other
describe the orientation of magnetic domains in a magnet.
roughly aligned
explain how the magnetic field is affected if a current-carrying wire is looped.
the magnetic field is intensified in the center of the loop
describe the orientation of an induced magnetic field to the moving electrical charge.
the magnetic field is perpendicular to the direction of the moving charge
identify the 2 types of changes in a magnetic field that can induce current into a circuit.
directional or velocity changes
describe the positions of two waveforms when they are in phase, 90° out of phase, and 180° out of phase
exactly the same time and the crests and troughs are superimposed;
waveforms 90° out of phase will not cross a center point at the same time, and the crests and troughs do not overlap;
waveforms 180° out of phase will cross a center point at the same time, but the crests and troughs are opposite of each other.
