Physics Final Study Terms
Terms
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- heat of fusion
- amount of thermal energy required to change a substance to/from solid to/from liquid
- convection
- the thransfer of heat energy in a gas or liquid by means of currents in the heated fluid
- sound wave
- a longitudinal vibratory disturbance that travels ina medium, which can be heard in the approximate frequency range of 20-20,000 Hertz
- alternating current (ac)
- electrically charged particles that repeatedly reverse direction, vibrating about relatively fixed positions
- magnetic field
- the region of magnetic influence around either a magnetic pole or a moving charged particle
- magnetic domains
- clustered regions of aligned magnetic atoms; when these regions are aligned with one another, the substance containing them becomes a magnet
- natural frequency
- a frequency at which an elastic object naturally tends to vibrate, so that minimum energy is required to produce a forced vibration or to continue vibrating at that frequency
- electromagnet
- a magnet whose field is produced by an electric current; they are usually in the form of a wire coild with a piece of iron inside the coil
- real image
- an image formed by light rays that converge at the location of the image; may be displayed on a screen
- diverging lens
- a lens that is thinner in the middle than at the edges, causing parallel rays passing through it to diverge as if from a point
- beats
- a series ofalternate reinforcements and cancellations produced by the interference of two waves of slightly different frequency, heard as a trhobbign effect in sound waves
- sublimation
- the hcange of phase from solid to gas skipping liquid
- electromagnetic wave
- a wave emitted by vibrating electrical charges (often electrons) and composed of vibrating electric and magnetic fields that regenerate one another
- virtual image
- an image fromed by light rays that do not converge at the location of the image
- coulomb
- unit of electrical charge; equal to the total charge of 6.25*10^18 electrons
- series circuit
- an electric circuit in which electrical devices are connected so that the same electric current exists in all of them
- opaque
- the term applied to materials through which light cannot pass
- heat of vaporization
- amount of thermal energy required to change a substance to/from liquid to/from gas
- electromagnetic spectrum
- the range of electromagnetic waves extending in frequency from radio waves to gamma rays
- absolute zero
- the lowest possible temperature; the temperature at which all particles have their minimum kinetic energy
- parallel circuit
- an electric circuit in which electrical devices ar connected so that the same voltage acts across each one and any single one completes the circuit independently of all the others
- amplitude
- for a wave or vibration, the maximum displacement on either side of the equilibrium position
- electrically polarized
- term applied to an atom or molecule in which ht echarges are aligned so that one side has a slight excess of positive charge and the other side has a slight excess of negative charge
- transparent
- the term applied to materials through which light can pass in straight lines
- sonic boom
- the loud sound resulting from the incidence of a shock wave
- interference
- the pattern formed by superposition of different sets of waves that produces mutual reinforcement in some places and cancellation in others
- calorie
- a unit of thermal energy, or heat (one of these is equal to 4.18 J)
- resonance
- the response of a body when a forcing frequency matches its natural frequency
- direct current (dc)
- electrically charge particles flowing in one direction only
- second law of thermodynamics
- heat never of itself flows from a cold to a hot substance
- bow wave
- the V-shape wave produced by an object moving across a liquid surface at a speed greater than the wave speed
- forced vibration
- the setting up of vibrations in an object by a nearby vibrating force
- condensation
- the change of phase from a gas to liquid
- magnetic force
- either the attracton of unilke magnetic poles or, between a magnetic field and a moving charged particle, it is a deflecting forcfe due to the motion of the partifcle; it is perpendicular to the velocity of the particle and perpendicular to the magnetic field lines; also it is greatest when the particle moves perpendicular to the field lines and zero when the particle moves parallel to the field lines
- converging lens
- a lens that is thicker in the middle than at the edges and refracts parallel rays passing thorugh it to a focus
- refraction
- the bending of a wave through either a non-uniform medium or from one medium to another, cauzed by differences in wave speed
- wave
- a disturbance or vibration propagated from point to point in a medium or in space
- radiation
- the transfer of energy by menas of electromagnetic waves
- electric power
- the rate of energy transfer, or rate of doing work, measured in watts
- wave speed
- the speed with which waves pass a particular point: frequency * wavelength
- third law of thermodynamics
- no system can ever reach an absolute temperature of 0 K
- diffraction
- the bending of light as it passes around an obstacle or thorugh a narrow slit, causing the light to spread and produce light and dark fringes
- frequency
- the number of vibrations per unity time, for a wave the number of crests that pass a particular point per unit time
- ampere
- the unit of electric current equivalent to 1 coulomb per second (6.25*10^18 electrons per second)
- photoelectric effect
- the emission of electrons from a metal surface when light shines on it
- transverse wave
- a wave in which the medium vibrates in a direction perpendicular (transverse) to the direction in which the wave traves; eg. light
- additive primary colors
- the three colors - red, blue, and green - that when added in certian proportions produce any other oclor in the visible light spectrum
- reflection
- the return of light into the medium from which it came
- subtractive primary colors
- the three colors of absorbing pigments - magenta, yellow, and cyan - that when mixed in certain proportions reflect anyh other color in the visible-light spectrum
- polarization
- the alignment of the transverse electric vectors that make up electromagnetic radiation
- interference
- the result of superposing tow or mor waves of the same wavelength
- wavelength
- the distance between successive crests, troughs, or other identical parts of a wave
- electromagnetic induction
- the induction of voltage when a magnetic field changes with time; if the magnetic field within a closed loop changes in any way, a voltage is induced in the loop
- heat
- the thermal energy that flows from an object at highter temperature to one at lower temperature, commonly measured in joules or calories
- law of reflection
- the angle of incidence is equal to the angle of reflection
- first law of thermodynamics
- a restatement of the law of energy conservation, usually as it applies to thermal systems: when heat flows into or out of a system, the gain/loss of heat is equal to the heat transferred
- longitudinal wave
- a wave in which the medium vibrates in a dirction parallel (longitudinal) to the direction in which the wave travels; eg. sound
- shock wave
- the cone-shaped wave created by an object moving at supersonic speed through a fluid
- electrical resistance
- the property of a material that resists the flow of charged particles thorugh it; measured in ohms
- diffuse reflection
- reflection in irregular directions from an irregular surface
- Ohm's law
- the statement that the current in a circuit varies in direct proportion to the voltage across the circuit and inversely with the circuit's resistance: current = voltage/resistance
- photon
- a particle of light, or the basic packet of electromagnetic radiation
- evaporation
- the change of phase from liquid to gas
- temperature
- a measure of the hotness of an object, related to the average kinetic energy per molecule, measured in degrees Ceisius, Fahrenheit, or kelvins
- thermal energy
- the total energy (kinetic plus potential) of atoms and molecules that make up a substance
- boiling
- rapid evaporation that takes place within a liquid as well as at its surface
- melting
- the change of phase form solid to liquid
- conduction
- the thranfer of heat energy by collisions between the particles in a substance (especially a solid)
- hertz
- the SI unit of frequency, equal to one vibration per second
- generator
- an electromagnetic induction device that produces electric current by rotating a coil within a stationary magnetic field; converts mechanical energy into electrical energy
- complementary colors
- any two colors that when added to each other produce white light
- period
- the time required for a vibration or a wave to make a complete cycle; inverse of frequency
- motor
- a device employing a current-carryinhg coil that it sforced to rotate in a magnetic field; converts electrical energy into mechanical energy
- freezing
- the change of phase from liquid to solid
- standing wave
- a stationary wave pattern formed in a medium when two identical waves pass through the medium in opposite directions
- refraction
- the bending of an oblique ray of light when it passes from one transparent medium to another
- Faraday's law
- an electric field is induced in any region of space iun which a magnetic field is changing with time; the magnitude of the induced electric field is proportional to the rate at which the magnetic field changes
- voltage
- a form of electrical pressure; equal to the potential energy divided by the charge
- electric current
- the flow of electric charge that transports energy from one place to another; measured in amperes
- Doppler effect
- the change in frequencey of wave motion resulting from the motion of the wave source and/or receiver
- Maxwell's counterpart to Faraday's law
- a magnetic field is induced in any region where an electric field is changing with time; the magnitude of th einduced magnetic field is proportional to the rate at which the electric field changes
- specific heat capacity
- the quantity of heat per unit mass required to raise the temperature of a substance by 1 degree Celsius (or Kelvin)
- Coulomb's law
- The electrical force between two charged bodies is directly proportional to the product of the charges and inversely proportional to the square of the distance between them: F=k*q1*q2/(d squared)