| Question | Answer |
| Coulomb | Unit of charge, "C" 1 C = charge of 6.24 x 10^18 electrons |
| Coulomb's law | For charged particles or objects that are small compared with the distance between them, the force between the charge varies directly as the product of the charges and inversely as the square of the distance between them |
| conservation of charge | charges never created nor destroyed |
| fundamental rule of electrical phenomena | like charges repel; opposite charges attract |
| charge | attracting and repelling behavior |
| electrical forces | billions times stronger than gravitational forces |
| electrostatics | electricity at rest |
| laser | light emitted when atom is stimulated and stimulates other atoms |
| coherent light | in phase |
| Incoherent light | out of phase |
| Diffraction grating | separation of light into colors arranged according to frequency |
| Monochromatic light | Single frequency |
| Diffraction | any bending of a wave by means other than reflection or refraction |
| Huygen's principal | every point on any wave front can be regarded as a new point source of secondary waves |
| diverging lens | virtual, reduced, right-side up |
| converging lens beyond one focal length | real, inverted |
| converging lens within one focal length | virtual, magnified and right-side up |
| converging lenses important rays | 1. ray parallel to principal axis bent in same direction as if it came from focal point. 2. through center goes straight. 3. ray headed to focal point on far side bends so emerges parallel |
| real image | an image that is formed by converging light rays and that can be displayed on a screen |
| virtual image | rays that reach the eye that act as if they came from an image position |
| magnification | when image is observed through wider angle with the use of a lens |
| focal length | distance between center of the lens and focal point |
| focal point | point at which rays of light converge where beam of light is parallel to principal axis converges |
| principal axis | line joining centers of curviture |
| diverging lens | rays diverge |
| converging lens | makes rays converge at a single point |
| lens | Piece of glass that has just the right shape, bends parallel rays of light so that they cross and form an image |
| optical fibers | pipe light from one place to another through total internal reflection |
| critical angle | beam no longer emerges into air above surface |
| total internal reflection | when angle of incidence greater than critical angle |
| dispersion | separation of light into colors arranged according to frequency |
| mirage | layer of hot air near the ground, light speeds up near the ground and causes bending of rays. Makes the image appear upside down. Looks like it's reflected, but it's refracted |
| wave fronts | lines that represent the positions of different crests. Waves move perpendicular to wave fronts. |
| refraction | when one part of a wave is made to travel slower (or faster) than another part, causing the wave to bend |
| diffuse reflection | light incident on a rough surface, reflected in many directions |
| law of reflection | Angle of incidence = angle of reflection |
| angle of reflection | angle made by reflected ray and the normal |
| angle of incidence | angle made by incident ray and the normal |
| normal | 90 degrees from surface. forms angles of incidence and reflection. |
| reflected rays | reflected off surface |
| incident rays | onto surface |
| reflection | wave reaches a boundary between two media, some or all the wave bounces back into the first medium |
| spectroscope | analyzes spectrum of element |
| scatter | let off beams in different directions |
| primary colors of paint ("Subtractive Primary Colors") | magenta, yellow, cyan |
| primary colors | red, blue, yellow. Make any colors with light |
| color mixing by addition | light, reflect colors you want to see |
| color mixing by subtraction | paints, absorb colors to leave one to be reflected |
| complimentary colors | add one additive primary + the color created by the other two = white light |
| additive primary colors | Red, green, blue, yield the greatest range of colors |
| green + blue | cyan |
| blue + red | magenta |
| red + green | yellow |
| radiation curve | measures light brightness |
| brightest colors | green/yellow |
| pigment | material in glass that absorbs colored light |
| color of a transparent object | depends on the color of light it transmits |
| black | absence of light, absorbs all frequencies |
| white light | combination of all visible light |
| spectrum | mixture of all the colors of the rainbow |
| polarization | the alligning of vibrations in a transverse wave, usually by filtering out waves of other directions |
| opaque | materials that absorb light without reemission |
| infrared waves on glass | vibrate entire structure of glass. increases temperature of glass, but is not reemitted. |
| ultraviolet on glass | close to natural frequency. causes many vibrations and collisions between atoms thats energy is lost as heat, not light. |
| transparent | allow light to pass through |
| electromagnetic waves | light energy that is emitted by accelerating electric charges. Partially electric, partially magnetic. |
| light year | distance light travels in one year |
| Albert Michaelson's experiment | Light source pointed at octagonal mirror, reflects off, goes to mirror on a mountain, reflects back into eye piece. Measure amount of time to go distance. Spins the mirror until it matches up again, and then the time for mirror to go 1/8 of a turn = speed of light = 300000 km/sec |
| speed of light as calculated by Roemer | Speed of light = extra distance traveled / extra time measured |
| photons | light particles |
| frequency of beats for two waves | fbeat = f1-f2 |
| beats | 2 tones slightly different frequency sounded together, causes fluctuation of loud and soft |
| resonance | frequency of a forced vibration of an object matches the object's natural frequency and causes a dramatic increase in amplitude. |
| natural frequency | minimum energy required to produce forced vibrations and to continue vibrations |
| decibel (dB) | unit of intensity, 10 dB means x10 |
| loudness | subjective, related to intensity. greater intensity = greater loudness |
| intensity of a sound | objective, amplitude squared |
| rarefaction | area of low pressure in longitudinal wave |
| compression | pulse of compressed air in a longitudinal wave |
| ultrasonic | above 20000 Hz, cannot hear |
| infrasonic | below 20 Hz, cannot hear |
| pitch | subjective interpretation of the frequency of a sound. Higher pitched, higher frequency |
| sounding boards | original vibration stimulates vibrations of something larger (sounding board). Vibrating material sends disturbance through medium. |
| sonic boom | conical shell of compressed air reaches listeners on the ground |
| shock wave | 3D bow wave |
| bow waves | V-shaped crests created when bug outruns speed of waves |
| supersonic | faster than speed of sound |
| red shift | decrease in the frequency of light |
| blue shift | increase in the frequency of light |
| Doppler effect | change in frequency due to motion of the source (or receiver) |
| reflected wave | reflected waves off a wall |
| incident wave | original wave created by a vibration |
| antinodes | positions on standing wave with largest amplitudes, halfway between nodes |
| nodes | parts of rope that remain stationary in a standing wave, results of destructive interference |
| destructive interference | crests align with troughs and cause decreased amplitude |
| constructive interference | crests lined up with crests and troughs with troughs |
| interference pattern | caused by more than one vibration existing at the same time in the same space |
| longitudinal wave | motion of the medium is parallel to direction in which a wave travels |
| transverse wave | motion of the medium is at right angles to the direction in which a wave travels |
| disturbance | energy transferred from a vibrating source to a receiver in a medium |
| Source of all waves | vibrations |
| hertz (Hz) | Unit of frequency, 1 cycle per second = 1 Hz |
| frequency | how often a vibration occurs, Hz |
| wavelength | distance from top of one crest to top of the next one |
| amplitude | distance from midpoint to crest, maximum displacement |
| midpoint | straight dashed line |
| troughs | low points |
| crests | high points |
| sine curve | curve of waves |
| simple harmonic motion | back-and-forth vibratory motion |
| period | time is takes for a back and forth swing |
| pendulum | swings back and forth, simple harmonic motion |
| wave | wiggle in space and time |
| vibration | wiggle in time |
| heat engine | device that changes internal energy into mechanical work. Only some heat transformed to work. |
| second law of thermodynamics | 1. heat will never itself flow from a cold object to a hot object. 2. when work is done by a heat engine running between two temperatures, T hot and T cold, only some of the input heat at T hot can be converted to work, and the rest is expelled as heat at T cold. 3. Natural systems tend to proceed toward a state of greater disorder. |
| adiabatic | process of compression or expansion of a gas so that no heat enters or leaves a system |
| -work = change in internal energy | work done ON a system, can increase internal energy |
| First law of thermodynamics | whenever heat is added to a system, it transforms into an equal amount of some other form of energy |
| absolute zero | 0K |
| thermodynamics | the study of heat and its transformation into mechanical energy |
| billiard-ball physics | balls bump into each other: some gain kinetic energy, some lose kinetic energy |
| vapor | molecules in the gaseous phase |
| evaporation | change of phase from a liquid to a gas at the surface of a liquid |
| radiation | heat transferred by electromagnetic waves: radiant energy |
| why does rising warm air cool? | warm air expands because less atmospheric pressure higher up. Expanding air cools. |
| what causes winds | Convection currents. Uneven heating of the earth. |
| convection | heating occurring by currents in a fluid |
| good insulators | poor conductors, transfer heat slowly |
| good conductors | metals, loose outer electron shells |
| conduction | when heat transfers through a metal. Within materials in direct contact |
| c of H2O | 1 cal/degree C |
| specific heat capacity | the specific heat capacity of any substance is defined as the quantity of heat required to raise the temperature of a unit of mass of the substance by one degree C |
| kilocalorie | 1000 calories, more common than the cal |
| calorie | amount of heat required to raise the temperature of 1 g of water by 1 degree C |
| internal energy | total energy of a substance |
| thermal equilibrium | when two object are the same temperature |
| Thermal contact | When heat flows from one object to another |
| heat | energy that transfers from one object to another because of temperature difference between them. Warmer to cooler. |
| Absolute 0 | 0K, lowest possible temperature, no kinetic energy to give up |
| Fahrenheit scale | 32 = freeze. 212 = boil |
| celsius scale | 0 = freeze. 100 = boil |
| temperature | quantity that tells how hot or cold something is |
| lift | pressure on wings greater on bottom than top causes a net upward force |
| eddy | Turbulent flow follows changing curling path |
| streamlines | smooth paths of bits of fluid. Fluid follows along the same path as bit of fluid in front of it. |
| Bernoulli's Principal | When the speed of a fluid increases, the pressure drops |
| Boyle's Law | P1V1=P2V2. Produce of pressure and volume is constant with constant temperature |
| altimeter | determines altitude, atmospheric pressure less at higher altitudes |
| aneroid barometer | small metal box exhuasted of air, flexible lid. Lid bends in and out with pressure changes |
| barometer | instrument used for measuring the pressure of the atmosphere |
| atmospheric pressure | the weight of air |
| Archimedes' Principal | An immersed object is buoyed up by a force equal to the weight of the fluid it displaces |
| buoyant force | upward force exerted on object. Greater at greater depth. |
| buoyancy | Apparent loss of weight of objects when submerged in a liquid |
| total pressure | liquid pressure + atomic pressure |
| liquid pressure | weight density x depth |
| Pressure | force/area |
| Elastic limit | Distance at which permanent distortion occurs |
| Hooke's law | Amount of stretch or compression (x) is directly proportional to applied force (F). F ~ x. F=kx |
| inelastic | materials that do not resume their original shape |
| elasticity | Property of a body by which it experiences a change in shape when a deforming force acts on it, and by which it returns to its original shape when the deforming force is removed |
| specific gravity | standard measure of density. Ratio of density of an object / density of water |
| Weight density | weight per volume. weight density = weight/volume |
| density | how much matter is squeezed into a given space. D = m/V |
| crystals | structures with regular geometric shapes |
| Atomic number | Number of protons in an element |
| Isotopes | Atoms of elements with different numbers of neutrons |
| Nucleus | Central region of atom. Made of protons and neutrons |
| Brownian Motion | Perpetual movement of atoms |
| Element | made up of atoms, building blocks of life |
| Einstein's special theory of relativity | mass is simply a form of energy. E=mc^2 |
| time dilation | when time is stretched due to speed |
| c is | constant |
| Second Postulate of Special Relativity | The speed of light in empty space will always have the same value regardless of the motion of the source or the motion of the observer |
| W =Mg/v | Weight density |
| vsound = 340 m/s | Velocity of sound |
| 1/o + 1/i = 1/f | Thin lens equation. o=object distance. i=image distance. f=focal length |
| F = kq1q2/d2 | force of electricity |
| n = c/v | Index of refraction = speed of light / velocity |
| n sinΘ = n' sinΘ' | Snell's law |
| Θi = Θr | Law of reflection |
| T = 2∏ √(L/g) | Period of a simple pendulum |
| f = 1/T | Frequency = 1/Period |
| fλ= v | Frequency x wavelength = velocity of a wave |
| cwater 1 cal/g˚C | Specific heat of water |
| Dwater = 1 g/cm3 = 1000 kg/m3 | Density of water |
| Peg = mgh | Gravitational potential energy |
| KE = (mv2)/2 | Kinetic energy |
| ∆Q = ∆U + W | Whenever heat is added to a system, it transforms to an equal amount of some other form of energy. (An increase in internal energy or external work done by the system) |
| e ideal = TH - Tc / TH | Ideal efficiency. Temperatures must be expressed in Kelvins. |
| P1V1=P2V2 | Boyle's Law. Product of pressure and volume is constant with constant temperature. |
| Q = mc∆T | Quantity of heat - mass x specific heat capacity x change in temperature |
| 1 cal = 4 J | Calories to Joules |
| 0˚C = 273 K | Celsius to Kelvin |
| g = 10 m/s/s | Gravity |
| W = Fd | Work = Force x distance |
| P = F/A | Pressure = force/area |
| F = k∆x | Hooke's law. Amount of stretch or compression (x) is directly proportional to applied force (F). F ~ x |
| D = M/V | Density = mass/volume |
| E = mc2 | Amount of rest energy E |
| F = Gm1m2/d2 | Force of gravity |
202 cards - created feb 23, 5:19pm