absolute uncertainties | Plus or minus the uncertainty |
absolute zero | The lowest temperature possible zero K |
acceleration | The rate of change of velocity |
accurate measurement | close to the accepted value |
activity | The rate of decay |
adiabatic transformations | No exchange of heat |
air resistance | The force of air opposing motion |
air wedge interference | The interference of light reflected off to angled glass plates |
albedo | The ratio of scattered light to incident light |
Algodoo | application used to simulate motion |
alpha particles | Helium nuclei emitted by unstable nuclei. |
alpha scattering experiment | High-speed positive particles fired at a thin gold foil. |
alternating current (AC) | Electric current that changes direction and magnitude. |
alternators | A rotating magnet in a coil. |
ammeters | Device for measuring current. |
amp (unit) | The Unit of current same as Coulomb per Second |
Ampere | 1A causes a force of 2 x 10^-7 N between to long conductors 1 m apart in a vacuum |
amplitude | Height of a wave measured from equilibrium position |
amplitude | The maximum displacement of a pendulum. |
ancient Greeks | Philosophers a long time ago |
angle of incidence | The angle between the normal and the incident ray. |
angle of reflection | The angle between the normal and the reflected ray. |
angle of refraction | The angle between the Normal and the refracted ray. |
angular displacement | The angle swept out by the radius. |
angular frequency | The angle swept out per unit time. |
Angular momentum | mvr |
angular velocity | The angle swept out per unit time |
annihilation | particle + antiparticle = energy but no mass |
antimatter | Matter made up of anti particles |
antineutrinos | Antiparticle of neutrino |
antinodes | Positions on a standing wave with zero amplitude. |
antireflective coating | An application of thin film interference |
apparent brightness (stars) | Brightness from the Earth |
apparent magnitude (stars) | Brightness from 10 pc |
area under a-t graph | change in velocity |
area under force - time graph | Work |
area under force distance graph | Work |
area under graph | area under the line |
area under v-t graph | displacement |
asteroids | Rocks orbiting the sun |
astronomical units | Sun - Earth distance |
atmospheric pressure | The pressure exerted by air. |
atom bombs | Application of an accelerating chain reaction. |
atomic lattice | A regular arrangement of atoms |
atomic line spectra | The spectrum formed when a low pressure gas is excited. Evidence of discrete electron energy levels. |
atomic nuclei | Heavy, small, positive centre of an atom |
atoms | Smallest particle of an element. |
attenuation | Reduction in amplitude |
Aurora Borealis | Glow in the night sky in the north due to the interaction betweencharged particles and the atmosphere |
average value of sine function | 00-Jan |
average velocity | Displacement / time |
average velocity | displacement/time |
Avogadro's number | The number of particles in a mole. |
background radiation | Radiation in a room due to naturally occurring radioactive material |
balanced forces | Condition for no acceleration. |
baryons | A group of particles including proton and neutron. |
batteries | Cells in series. |
BE (see binding energy) | The work done to take a nucleus apart or energy released when it is formed. |
becquerel (unit) | Unit of activity. |
best fit line | A line drawn as close as possible to the data points |
beta particles | An electron formed when a neutron changes to a proton. |
Big Bang | A model for the start of the universe. |
big crunch | A model for the end of the universe. |
binary stars | Pairs of stars that orbit each other. |
binding energy (BE) | The work done to take a nucleus apart or energy released when it is formed. |
black holes | The fate of massive stars. |
blue shift | Doppler shift in approaching sources of light. |
Bohr model | Atomic model assuming angular momentum to be quantised |
boiling | Change of state from liquid to gas. |
boron control rods | Absorb neutrons slowing down the chain reaction |
Brownian motion | The randon motion of smoke particles knocked about by air molecules. |
buoyancy | Upward force due to displacement of fluid. |
capacitance | charge/potential |
capacitors | Charge storing devices, usually parallel plates. |
capacitors in parallel | C = C1 + C2 |
capacitors in series | 1/C = 1/C1 + 1/C2 |
Carnot cycles | A thermal cycle comprising of isothermal and adiabatic changes. |
cells | A single unit of a battery |
Celsius scale | Temperature scale based on the melting point (0) an boiling point (100) of water. |
Celsius scale | Temperature scale based on the freezing and boiling of water. |
centre of mass | Point at which forces can be taken to act. |
centripetal acceleration | Acceleration towards the centre of a circle |
centripetal force | Force that causes circular motion, directed towards the centre. |
Cepheid variable | A star with varying brightness. Time period is related to luminosity |
CERN | A facility near Geneva with a huge particle accelerator. |
chain reactions | A nuclear reaction where one fission initiates another. |
Chandrasekhar limit | Defines the maximum size of a white dwarf. |
circular motion frequency | Number of complete cycles per second. |
circular wavefronts | Wave fronts from a point source. |
closed universe | A universe that stops expanding and then begins to contract. |
cloud chamber | Particle detector showing paths as vapour trails |
coal-fired power stations | Coal is burnt to give heat used to drive a turbine |
coalitions | Two bodies join together, example of inelastic collision |
coherence | Light sources with the same frequency and constant phase relationship. |
coherent | similar amplitude,same frequency constant phase difference. |
colour | related to wavelength |
colour charge | The property of quarks responsible for the strong force. |
colour mixing | red + green = yellow, green + blue = cyan, red + blue = magenta |
comets | Balls of ice with long tails orbiting the Sun. |
components | Fcos(angle) and Fsin(angle) |
Compton scattering | Interaction between a photon and electron demonstrating particle nature of light. |
concave lenses | Caves go in |
conduction | Transfer of heat via molecular vibration. |
conductors (electricity) | Materials that allow the flow of charge, mainly metals as they have free electrons. |
conservation of charge | Charge can not be created or destroyed. |
conservation of energy | Energy can neither be created or destroyed. |
conservation of momentum | Provided no external forces act, the momentum of a system of bodies is always the same. |
constellations | Ancient civilizations playing join the dots with the stars. |
constructive interference | Addition of waves that are in phase. |
continuous spectra | Spectra produced when e.g. Solids are heated |
convection | Transfer of heat in fluids due to reduced density with rise in temperature |
convex lenses | A converging lens, not a cave. |
cornea | The front surface of the eye, also acts to focus light. |
cosmic background radiation | Microwaves that are the result of expanding space increasing the wavelength of high energy radiation that existed in the early stages of the universe. |
cosmic rays | High energy particles entering the Earths atmosphere |
coulomb (unit) | The unit of charge. |
Coulomb's law | The force between two charged points is proportional to the product of their charge and inversely proportional to their separation squared. |
critical angle (refraction) | Angle on incidence when angle of refraction = 90 degrees |
critical damping (oscillations) | System returns to equilibrium without passing through it. |
critical density (universe) | Density of universe that predicts that expansion stops at infinite size. |
CT scans | A 3D X-ray |
cubic | of the form y= Ax^3 +Bx^2 + Cx + D |
damping | The reduction in amplitude of an oscillator due to an opposing force. |
dark energy | The reason why the expansion of the universe is accelerating. |
dark matter | Large amounts of matter predicted to exist in the universe but not seen. |
Davidson‚Germer experiment | An electron scattering experiment. Evidence for the wave nature of electrons. |
DC | Direct Current |
de Broglie hypothesis | All matter has wave like nature. |
de Broglie wavelengths | h/p |
decay | The changing of a nucleus by the emission of radiation. |
decay chains | A series of radioactive decays. |
decay constants | High value means rapid decay |
decimal places in value | same as uncertainty. |
deep inelastic scattering | Evidence for the existence of quarks. |
degradation of energy | Energy becomes more spread out. |
density | Mass/volume |
depleted uranium | Non fissile Uranium |
derived units | Not fundamental. Like density = mass/volume |
destructive interference | Two waves coincide and cancel out |
diffraction | The spreading out of a wave as it passes through a narrow opening. |
diffraction envelope | The effect of diffraction on multiple slit interference |
diffraction grating | Many equaly spaced parallel slits. |
dipoles | pairs of + and - charges |
direct current (DC) | Always in the same direction |
discharge tubes | Tubes of low pressure gas excited by an electric field. |
dispersion | The splitting up of colours by a prism. |
displacement | Distance moved in a particular direction. A vector quantity. |
displacement‚time graphs | Graph of displacement vs time. |
distance | Path length. |
Doppler effect | Change of frequency due to relative motion of source and observer. |
double slit experiment | Passing light through two parallel slits to give interference fringes. |
drift velocity | Average velocity of electrons moving through a conductor. |
dynamos | A rotating coil in a magnetic field used to produce electricity. |
echo | Reflection of sound |
EEEow | Sound of car passing stationary observer. |
efficiency | Energy delivered/Energy generated |
Einstein rings | Rings of light caused by the curvature of space - time by massive bodies. |
Einstein's postulates | Speed of light in a vacuum is constant and all inertial observers are the same. |
Einstein‚ principle of equivalence | Accelerating frames of reference are equivalent to those in gravitational fields. |
elastic collisions | KE and momentum conserved |
elastic collisions | Momentum and KE conserved. |
elastic PE | kx^2/2 |
electric charge | The property responsible for the electric force. |
electric currents | Movement of charge. |
electric field strength | Force/charge |
electric forces | The force between charged bodies |
electric potential | The work done per unit charge in taking a small positive test charge from infinity to a point. |
electric potential energy | The work done per unit charge in moving a small positive test charge from A to B |
electric power | p = VI = I^2R = V^2/R |
electromagnetic induction | Generation of EMF in a conductor due to changing magnetic field. |
electromagnetic waves | The propagation of changes in electric and magnetic field |
electron | A negatively charged particle that can be removed from an atom. The charge carrier in metals. |
electron energy levels | The discrete energies of atomic electrons. |
electron guns | electrons liberated from a hot wire accelerated through a potential difference. |
electron-volt (unit) | The energy gained by an electron accelerated by a PD of 1 V |
elements | Atoms with different numbers of protons. |
EM waves | The propagation of changes in electric and magnetic field |
emf | The amount of chemical / mechanical energy converted to electrical per unit charge in a battery / generator. |
emissivity | Power emitted per unit area by a body / power emitted per unit area by a black body |
energy | The ability to do work / Transferred when body A does work on body B. |
energy density | Energy per unit volume |
engines | Convert heat into work. |
enrichment | The process of increasing the % of fissile material in nuclear fuel. |
equation of state | PV = nRT |
equilibrium position | The position in which a system come to rest. |
equipotential lines | Lines joining points of equal potential. |
equipotential surfaces | Surfaces joining points of equal potential. |
error bar | A line drawn on a point to represent uncertainties |
errors | Uncertainties in measurement. |
escape speed | Speed required for a projectile to reach an infinite distance from a massive body. |
escape speed from Earth | 11 km/s |
evaporation | Liquid changing to gas at the surface. |
events | Charges taking place at a given position and time. |
exchange forces | Forces that are the exchange of particles |
explosions | Two bodies pushed apart, example of inelastic collision |
exponential decay equation | y = mx + c |
exponential equations | y=e^x |
fairies | Small people with wings. |
Faraday's law | Induced EMF equals the rate of change of flux enclosed. |
Feynman diagrams | Used to represent particle interactions, lines do not represent particle paths. Time progresses left to right (sometimes drawn with time going up) |
Feynman rule 1 | straight lines are particles wavy lines are photons |
Feynman rule 2 | each vertex has 2 straight one wavy line |
Feynman rule 3 | time progresses left to right (sometimes drawn with time going up) |
Feynman rule 4 | particles point forwards in time antiparticles backwards. |
Feynman rule 5 | there is always one arrow entering and one leaving. |
field lines | Show strength (line density) and direction (arrow) of field. |
first law of thermal dynamics | work done = gain in internl energy + heat lost |
flat universe | there is always one arrow entering and one leaving. |
Fleming's left hand rule | Motors: First- field, seCond - current, thuMb - motion |
Fleming's right hand rule | Generators: First- field, seCond - current, thuMb - motion |
fluorescent | A material that emits light when hit by electrons. |
flux (magnetic fields) | Flux density x Area |
flux density | Measure of the strength of magnetic field B = F/IL |
force | Push and pull |
force on a charge | F = Bqv |
force on a wire | F = BIL |
forced oscillation | An oscillation pushed by an external force. |
frames of reference | A coordinate system an observer uses to take measurements. |
free body diagrams | Forces drawn that act on a body but not forces exerted by the body |
free electrons | Electrons free to move about in conductors. |
frequency | Number of complete cycles per second. |
frequency (wave) | The number of complete wavelengths passing a point per second. |
frictional force | Force that opposes the relative motion of two in contact surfaces. |
fringe spacing | distance between bright lines in an interference pattern. |
fuel density | energy/volume |
fuels | Materials that can be burnt giving out heat energy. |
fundamental units | kg, m, A, s |
g (acceleration due to gravity) | 9.8 m/s^2 |
G (universal gravitational constant) galaxies | F = GMm/r^2 |
Galilean transforms | Non relativistic transformations between frames of reference. |
gamma radiation | High energy EM radiation. |
gas pressure | due to change in momentum of gas molecules hitting a wall. |
gases | Made of a large number of randomly moving atoms with no interatomic force. |
gauge bosons | Exchange particles e.g. photon |
Geiger‚Marsden experiment | Classic alpha scattering by Gold foil. |
general relativity | Relativistic theory of gravity. |
generations | Classification of fundamental particles |
generator | Converts KE into electrical anergy |
GeoGebra | Mathematics application |
geostationary satellites | Communication satellites with 1 day time period. |
global warming | Rise in temperature due to enhanced greenhouse effect. |
gluons | Exchange particle responsible for the strong force between quarks. |
GM tube | Particle detector |
gradient of acceleration time graph (constant acceleration) | zero |
gradient of s-t graph | velocity at one moment in time. |
gradient of v-t graph | acceleration |
gradients | Change in y / Change in x |
gravitational fields | Region of space where a mass experiences force. |
gravitational mass | m = F/g |
gravitational potential | Work done per unit mass taking a small test mass from infinity to a point. |
gravitational potential energy | Work done taking a body from infinity to a point. |
gravitational red shift | Increase in wavelength of receding galaxies due to Doppler shift |
hadrons | A particle made of quarks. |
Hafele‚Keating experiment | A relativistic experiment sending clocks around the Earth. |
half-lives | Time taken for radioactive activity to reduce by half. |
harmonics (sound) | Multiples of the lowest frequency standing wave formed in strings and pipes. |
Harvard classification | Be A Fine Girl Kiss Me. Stellar classification |
heat | Transferred when a hot body is in thermal contact with a cold one. |
heat capacity (see specific heat capacity | Amount of heat required to raise the temperature of a body by 1 K. |
heat pumps | Take heat from a cold body to a hot one. |
Heisenberg's uncertainty principle | ΔxΔp = h/4π or ΔtΔE = h/4π |
hertz (unit) | Cycles per second |
Hertzsprung‚Russell (HR) diagrams | Stellar diagrams on which stars are plotted according to luminosity and temperature. |
Higgs boson | Fundamental particle responsible for mass. |
Hooke's law | Force is proportional to extension. |
horizontal component (angle A measured to horizontal) | FcosA |
horizontal motion (projectile) | constant velocity |
horse power (unit) | 0.75 kW |
Hubble constant | Constant relating recessional velocity of galaxies to distance from the Earth. |
Huygens construction | A wavefront behaves as if made of an infinite umber of wavelets. |
hydroelectric power | PE stored in bodies of water converted to electrical energy. |
hydrogen | Smallest element, proton number = 1 |
hydrogen bomb | Uses fussion to create an explosion. |
hysteresis | Magnetic memory |
I-V graphs | Current vs Voltage used to determine resistance. |
ice cores | Samples of ice used to measure changes in the atmosphere over time. |
ideal gases | Obeys the gas laws. |
images | Positions where rays of light cross over. |
impulse | Change of momentum. |
Induced EMF in straight wire with velocity v perpendicular to field | BLv |
induction braking | Uses induced current to oppose motion. |
induction hotplates | Uses changing magnetic field to excite magnetic dipoles raising temperature. |
inelastic collisions | Momentum but not energy conserved. |
inertial frames of reference | A system of coordinates in which Newton's laws of motion are obeyed. |
inertial mass | Ratio Force/acceleration |
infrared (IR) radiation | EM radiation between red and microwave. |
instantaneous velocity | Velocity at one moment in time. |
Instantaneous velocity | very short displacement/time |
insulators (electricity) | Materials with no free electrons. |
intensity | Power per unit area. Proportional to A^2 |
interatomic force | Force between atoms, replulsive when close attractive when distant. |
interference | The addition of displacement when two waves meet. |
internal energy | Sum of KE + PE of molecules of a body. |
internal resistance | Resistance of internal components of a battery. |
inverse square relationship | y = k/x^2 |
ionization | Removal of electrons from an atom. |
iris | adjusts aperture of the eye |
iris | Part of the eye that controls size of apperture. |
isobaric transformations | Expansions / contractions where there is no exchange of heat. |
isochoric transformations | Constant volume expansions / contractions |
isolated systems | A system of bodies where no external forces act. |
isothermal transformations isotherms | Constant temperature expansions / contractions |
isotopes | Nuclei with the same proton number different neutron number. |
joule (unit) | Unit of energy. |
katabatic winds | Cold air coming down a mountain. |
Kelvin scale | Temperature scale based on the pressure of a fixed volume of gas. |
Kepler's third law | Time period of planets squared is proportional to orbital radius cubed. |
kilogram | Unit of mass. |
kilowatt-hours | Energy transferred when 1000 Watts of power is used for 1 hour. |
kinetic energy (KE) | The energy gained when work is done on a body to increase its speed. |
Kirchhoff's 1st | sum of currents into junction = sum of currents out of junction |
Kirchhoff's 2nd | Around a closed loop, sum of EMF's = sum of PD's |
Large Hadron Collider (LHC) lasers | Particle accelerator at CERN |
Laser | A monochromatic, parallel source of light. |
latent heat | Heat required to change state. |
LCDs (liquid crystal displays) | Use polarisation to create images. |
length | distance between two points on an object |
length contraction | Reduction in length due to relative motion of object and observer. |
lenses | Used to bring light rays to / diverge them from a focal point. |
Lenz's law | Direction of induced current opposes change producing it. |
leptons | Fundamental particles with small mass. |
light | Visible part of EM spectrum. |
light bulbs | Convert electrical energy to light. |
light clocks | Imaginary timer used in relativity explanations. |
light dependent resistors (LDRs) | Semi conductor device whose resistance depends on light intensity. |
light years | Distance travelled by light in one year. |
linear | of the form y = mx +c |
linear accelerators | Accelerate charged particles in straight lines. |
linear equation | of the form y = mx +c |
linear magnification | Ratio size of image/size of object |
linearization | Rearranging an equation so it is in the form y = mx +c |
liquid crystals | Change polarisation plane unless a Pd is applied. |
liquids | No fixed shape but fixed volume. |
logarithmic scales | Divisions increase by a constant factor usually 10. |
longitudinal waves | Disturbance in the same direction as propagation. |
Lorentz transforms | Transformations that take into account the constant velocity of light. |
Loudness | Related to amplitude |
luminosity | Total power radiated by a star. |
magnetic fields | Region of space where a small magnetic dipole experiences a turning force. |
magnetic north | End of a magnet that points north |
magnetic resonance imaging (MRI) magnets | Uses oscillations of nuclei in magnetic fields to form medical images. |
magnetic south | End of magnet that points south |
Malus's law | Intenity of polarised light is proportional to the square of the cosine of difference in plane of polarisation |
mass - energy equivalence | E = mc^2 |
mass defect | Mass of pparts - mass of nucleus |
mass spectrometers | Separate nuclei according to mass. |
measurement uncertainty | the uncertainty of the instrument and how it is used |
meltdown | Result of a nuclear reactor overheating. |
mesons | A particle made of two quarks |
metre (unit) | Si unit of length |
Michelson‚Morley experiment | Showed that the speed of light was not affected by motion relative to it's medium. |
microwaves | EM radiation with wavelegth of the order of mm. |
Milky Way | Our galaxy. |
Millikan photoelectric experiment | Uses stopping potential to measure KE of photo electrons. |
moderator | Used to slow down neutrons so they ate absorbed more easily e.g. Graphite |
molecules | Atoms held together by the interatomic force. |
molecules excitation | Increasing the KE of molecules. |
momentum | mass x velocity |
muons | A fundamental particle in the lepton family. |
natural frequency | Frequency of an oscillating system with no driving force. |
negative acceleration | change of velocity in a negative direction |
negative time | Before the clock started. |
negative work | If you do negative work you gain energy. |
neutral currents | Particle interactions with no exchange of charge. |
neutrinos | A group of fundamental particles with no charge and very small mass. |
neutron stars | Dense stars made of neutrons. |
neutrons | Neutral particles made of 3 quarks. Part of the nucleus. |
newton (unit) | SI unit of force. |
Newton's 1st | A body remains at rest or with constant velocity unless acted upon by an unbalanced force. |
Newton's 2nd law | F = ma |
Newton's 2nd law (momentm) | The rate of change of momentum of a body is directly proportional to the unbalanced force acting on that body and takes place in the same direction. |
Newton's 3rd Law | If body A exerts a force on body B then body B will exert and equal and opposite force on body A. |
Newton's laws of motion | 3 laws that relate force and motion. |
Newton's model | A static model of the universe. |
Newton's universal law of gravitation | All point masses attract all others with a force that is proportional to the product of their mass and inversley proportional to their separation squared. |
nodes | Points on a standing wave with zero amplitude. |
non-ohmic conductors | Conductors where current is not proportional to voltage |
normal force | The force perpendicular to two surfaces in contact |
nuclear fission | The splitting up of large nuclei |
nuclear force | The force between nucleons |
nuclear fuels | Fissile material used in nuclear reactors |
nuclear fusion | The joining of small nuclei |
nuclear magnetic resonance (NMR) | Using the vibration of nuclei in magnetic fields to produce medical images |
nuclear radiation | Particles emitted by unstable nuclei |
nuclear waste | The remaining material after fission |
nuclei (atoms) | Heavy centre of an atom |
nucleons | Protons and neutrons |
nuclides | Different nuclear forms. |
observers | Experimenters committed to make measurements in a given frame of reference |
Occam's razor | Simple is best |
ohm (unit) | Unit of resistance |
Ohm's law | Current is proportional to voltage |
ohmic conductors | Materials that obey Ohm's law |
oil-fired power stations | Use oil to produce electricity |
open universe | A model of the universe with continuous expansion |
Oppenheimer‚Volkoff limit | The minimum size for the formation of a black hole |
optical fibres | Thin fibres that transmit light by total internal reflection |
orbits | e.g. The moon orbits the Earth, entripetal force provided by gravity |
oscillating water columns | Convert wave power into electricity |
oscillation | A repeating cycle |
oscillations amplitude | Maximum displacement from equilibrium position |
outliers (graphs) | Points that don't lie on the best fit line |
pair production | Particle anti-particle pairs formed from photons |
parabolic paths | The trajectory of a projectile |
parallax | Shift of objects due to movement of observer |
parallel circuits | Components connected between the same points |
parsecs | Distance between stars that subtends an angle of one arcsecond |
particle accelerators | Devices that accelerate charged particles |
particle detectors | Devices that detect particles e.g. Geiger tube |
particle model | Model that describes matter as being made of particles |
Pauli exclusion principle | Particles with spin half can not occupy the same energy state |
Peak current and Voltage | Maximum values. |
pelamises | A device that converts wave power into electricity |
pendulums | Small bodies suspended on strings |
percentage uncertainties | Uncertainty divided by value as a percent |
permittivity (electric fields) | Constant relating electric force with charge |
phase angle | Angular difference between two oscillating bodies |
phase difference | Angular difference between two oscillating bodies |
photo gates | Devices used for measuring time elapsed |
photodiodes | Semi conducting devices that convert light into electricity |
photoelectric effect | Emission of electrons due to absorption of light |
photons | Particles of light |
photosynthesis | Conversion of carbon dioxide and water into carbohydrates in plants using energy from the sun. |
photovoltaic cells | Semi conducting devices that convert light into electricity |
pions | Particles made of two quarks part of the meson family |
pitch (sound) | Perception of frequency of sound |
planar wavefronts | Waves propagating in parallel lines |
Planck's constant | Constant relating photon energy and frequency |
planets | Large bodies orbiting the sun |
plasmas | Gases made up of ions |
plum pudding model (atoms) plutonium | Rutherford's model of the atom |
polar satellites | Satellites that orbit the poles |
polarization | Restricting the disturbance of a wave to one plane |
positive acceleration | change of velocity in a positive direction |
positive work | If you do positive work you lose energy |
positrons | The anti particle of electrons |
potential difference (p.d.) | The work done per unit charge in moving a small positive test charge between two points |
potential dividers | Series resistors used to produce a variable potential difference |
potential energy (PE) | The work done in placing a body in a position |
potential gradient | change in V / change in x |
potential wells | A minimum in potential energy |
Pound‚Rebka experiment | Measured the change in frequency when EM radiation travelled vertically |
power | Energy per unit time |
power lines | Cables used to trsnsmit electrical energy |
power loss (electricity) | Energy loss in power lines. |
power stations | Generate electrical energy. |
precise measurements | close to each other |
pressure | Force per unit area |
primary colours | Red, green, blue |
probability function | Function that gives the probability of the position of a particle |
probability waves | A wave function that gives the probability of the position of a particle |
projectile motion | Motion of a particle moving freely in a uniform gravitational field |
proper length | The length of an object measured by an observer at rest relative to it |
proper time | The time of an event measured by a clock at rest relative to the event |
proportional relationship | of the form y = mx |
proton-proton chains | The process of fusion producing energy in the sun |
protons | Positive particles made of three quarks present in the nucleus |
protostars | The early stage in the life of a star |
pupil | apperture of the eye |
PV diagrams | Pressure-volume graphs |
Pythagoras' theorem | Square of hypotenuse is equal to the sum of the square of the other two sides |
quantized energy | For example electrons can only exist in certain energy levels |
quantum chromodynamics (QCD) | The theory explaining the force between quarks |
quantum model | Atomic model describing the electron energies in terms of a probability function |
quantum numbers | Numbers defining electron energy states |
quantum tunneling | A particle can get past a barrier without climbing over it. |
quark confinement | The reason why quarks can not exist alone |
quarks | Fundamental particles that make up baryons and mesons |
radians | Measurement of angle. Arc length divided by radius |
radiation | Transfer of heat via electromagnetic waves. |
radiation absorption spectra | Produced when white light is passed through a low pressure gas |
radiation therapy | Using radioactive isotopes to kill cancer cells |
radiation-dominated universe | A time when universe was dominated by photons |
radio waves | Long-wavelength EM radiation |
radioactive dating | A way of using the decay of radioactive isotopes to determine age |
radioactive isotopes | Nuclei with the same proton number different neutron number. |
random errors | errors resulting from uncertainties in measuring device or conditions. |
range | horizontal distance travelled by projectile |
rate of change | dx/dt |
Rayleigh criterion | Two objects are resolved if the first minimum in the diffraction pattern of one coincides with the principal maxima of the other |
rays (waves) | Lines drawn at right angles to wavefronts |
real images | Points where rays cross |
red giants | Stars at the end of their life cycle |
red shift | Shift in wavelength due to the recession of sources of light |
reflection | What happens when light hits a mirror |
refraction | Change of direction of a wave when passing through a boundary between two media |
refractive indices | Sine of the angle of instance over angle of refraction |
refrigerators | Use thermic cycles to transfer energy from hot bodies to cold |
relative atomic mass | The mass of an atom relative to 1/12 the mass of a carbon 12 atom |
relative velocity | The velocity measured by a moving observer |
resistance | The ratio of potential difference / current |
resistivity | The resistance of a cubic meter of material |
resistors | Devices that reduce the current in a circuit |
resolution | The ability to distinguish two point objects |
resolvance | The ability to resolve spectral lines |
resonance | When an oscillating system is made to vibrate at its own natural frequency |
resonance curves | A graph of amplitude against forcing frequency |
resultant force | The vector sum of all forces acting on a body |
retina | light sensitive part of the eye |
right hand grip rule | thumb in direction of current fingers curl in direction of field |
root mean square current and voltage (rms) | The root of the mean of the squares. Gives same power as DC value |
rotation | Caused when a force does not act through the centre of mass |
Rutherford model | Plum pudding model |
sampling | The rate of taking measurements by a digital device |
Sankey diagrams | Flow diagrams |
satellites | Bodies that orbid the earth |
scalars | Quantities with magnitude but no direction |
second law | In any interaction the entropy will always increase |
seconds (time) | SI unit of time |
serendipity | Luck |
series circuits | Components connected in a line |
SHM KE | Max at equilibrium position |
SHM PE | Max at max displacement |
SHM toal energy | Constant = PE + KE |
SI units | International system of units |
sig figs in uncertainty | 1 or 2 |
simple harmonic motion (SHM) | When force is proportional to displacement from a fixed point and always acts towards that point |
simultaneity | Events taking place at the same time are not at the same time for all observers |
small angle approx. | SinA = A in radians |
Snell's law | Sine angle of incidence / Sine angle of refraction = Constant |
solar constant | Intensity of solar radiation incident at the earth |
solar energy | Using energy from the sun to produce electricity |
solenoids | Coils where the windings are side by side |
sonic boom | A bang caused by the accumulation of sound when a body travels at the speed of sound. |
sonometer | A single stringed musical instrument. |
sound | propagation of changes in pressure. |
special relativity | The study of relativity applied to inertial frames of reference. |
specific energy | enrgy/mass |
specific heat capacity | The amount of heat required to raise the temperature of 1kg of a substance by 1 K. |
specific latent heat (see latent heat) | The amount of heat required to change the state of 1 kg of a substance without change in temperature. |
spectrometer | A device used to view spectra |
Spectrum of light | Ranges from red (low frequency long wavelength) to blue (high frequency, short wavelength) |
speed | Distance travelled / time |
speed of light in a vacuum | c = 300,000,000 m/s |
spherical aberration | The outer rays passing through a convex lens are deviated more than the inner ones. |
spin | A propety of particles, can be 1/2, 1 or 0. can align or not align 1/2 + 1/2 = 1 or 0 |
spin (particles) | A property of all subatomic particles |
spring constant | Force/extension |
standing waves | Formed when a wave interferes with its reflection. |
states of matter | solid, liquid and gas |
Stefan‚Boltzmann law | Radiated power per unit area is proportional to thhe 4th power of absolute temperature |
stellar clusters | Groups of stars. |
step indexed fibres | Optical fibres made of layers with decreasing refractive index. |
stimulated emission | When the emmission of a photon is initiated by a photon on the same frequency. |
stopping (lenses) | Applying a small aperture to a lens to reduce spherical abberation. |
straight line graphs | y = mx + c |
strangeness | A property of subatomic particles expressed as a quantum number. |
stringed instruments | instruments with stretched strings e.g. Guitar |
strong force/interactions | The force between quarks. |
subsidiary maxima | Small maxima between pricipal maxima. (number of slits - 2) |
supernovas | Exploding stars. |
superposition | Vector addition of wave displacement |
suvat 1 (uvat) | a =(v - u)/t |
suvat 2 (suvt) | s = (u + v)t/2 |
suvat 3 (suat) | s =ut + at^2/2 |
suvat 4 (suva) | v^2 = u^2 + 2as |
suvat equations | A set of equations used to solve problems involving motion with constant acceleration. |
systematic errors | When the same error occurs in all measurements. |
temperature | Defines the direction of heat flow. Related to average KE of molecules. |
tension | When a force is applied via a string. |
tesla (unit) | Unit of magnetic flux density. |
thermal | Refers to systems where there is exchange of heat. |
thermal capacity | The amount of heat required to raise the temperature of a body by 1 K. |
thermal equilibrium | When there is no flow of heat between two bodies in contact. |
thermodynamic cycles | A series of transformations that begin and end at the same state. |
threshold frequency | The minimum frequency require for the emission of photo electrons. |
tidal power | Electrical energy generated from the flow of tides. |
time period | time for one revolution |
total internal reflection | occurs when light is incident on a boundary to a less dense medium. |
totally inelastic collisions | When bodies stick together. |
trajectory | path of a particle |
transformers | Coils with shared magnetic field. Np/Ns = Vp/Vs |
translational equilibrium | When the forces acting on a body add uo to give zero. |
transmutations | When a nucleus changes to another |
transverse waves | When the direction of disturbance is perpendicular to the direction of propagation. |
turbine | Creates rotation from the KE in moving fluids. |
twin paradox | One twin takes a high speed journey and returns to Earth younger |
ultrasound | High frequency, inaudible sound. |
ultraviolet (UV) light uncertainty | High freqency EM radiation, just outside the visible spectrum. |
uncertainty | How well you can define a quantity. |
uncertainty in a range of values | (max-min)/2 |
unified mass units | 1/12 of the mass of a carbon 12 atom. |
uniform electric field strength | E=V/d |
uniform fields | Parallel, equally spaced field lines. |
unstable nuclei | Nuclei that emit radiation changing into something with higher BE. |
upthrust | Same as buoyancy. |
variable stars | Stars with varying brightness. |
vector addition | nose to tail, resultant is line joining free nose to tail. |
vectors | Quantities with magnitude and direction e.g. Force |
velocity | Displacement / time |
velocity‚time graphs | Linear when acceleration is constant. |
vernier caliper | A sliding scale used to measure small lengths accurately |
vertical component (angle A measured to horizontal) | FsinA |
vertical motion (projectile) | constant negative acceleration |
Video analysis | Using LoggerPro to analyse motion in a video. |
volt (unit) | Unit of potential. Same as J/C |
voltmeters | Instrument for measuring PD. Ideally have infinite resistance. |
volume of a cube | L^3 |
volume of a sphere | 4/3 πr^3 |
W boson | Exchange particle in weak interactions |
watt (unit) | SI unit of power J/s |
wave particle duality | The theory that the position of particles given by a wave function. |
wave speed | frequency x wavelength |
wavefronts | Lines joining points on a wave that are in phase. |
wavelength | The distance between two consecutive, in phase points on a wave. |
waves | A physical phenomenon that diffracts and interferes |
weak force/interactions | Interactions involving neutrinos |
weight (gravitational force) | Force of attraction between a body and the Earth. |
weightlessness | Apparent lack of weight in free falling frames of reference. |
white dwarves | Small hot stars. After the main sequence. |
white light | a mixture of all the colours in he rainbow. |
Wien's law | The peak wavelength in the black body spectrum is inversely proportional to absolue temperature. |
wind instruments | Make use of standing waves in pipes. |
wind turbines | Convert KE in wind into electrical energy. |
wire chambers | A particle detector. |
work (energy transfer) | Force x distance moved in direction of force. |
work function (photoelectric effect) | Minimum energy required to liberate photo electrons. |
X-rays | High frequency EM radiation. |
X-rays diffraction | The result of passing X-rays through crystals. |
y intercept | Where a line crosses the y axis- |
zinc plate experiment | A demonstration of the photoelectric effect. |
zinc sulphide | A material used in the screens of electron tubes. |