GoConqr has a new look! Let us know what you think.

Sign up free

Flashcards

Defenitions (1)

lizabeth rawson physics A level English 200 cards

Cards in this deck (200)

  1. 1absolute scale of temperatureA scale for measuring temperature based on absolute zero and the triple point of pure water, with gradations equal in size to those of the Celsius scale; unit kelvin (K)
  2. 2absolute zeroThe lowest possible temperature, the temperature at which substances have minimum internal energy
  3. 3absorption coefficientA measure of the absorption of X-ray photons by a substance, also known as attenuation coefficient - SI unit m-I
  4. 4absorption line spectrumA set of specific frequencies of electromagnetic radiation, visible as dark lines in an otherwise continuous spectrum on spectroscopy. They are absorbed by atoms as
    their electrons are excited between energy states by absorbing the corresponding amount of energy in the form of photons - every element has a characteristic line spectrum
  5. 5accelerationThe rate of change of velocity, a vector quantity
  6. 6acceleration of free fallThe rate of change of velocity of an object falling in a gravitational field, symbol g
  7. 7acoustic impedanceThe product of the density p of a substance and the speed c of ultrasound in that substance - symbol Z, SI unit kgm-2g-l
  8. 8acoustic matching (or impedance matching)The use of two substances with similar acoustic impedance to minimise reflection of ultrasound at the boundary between them
  9. 9ActivityThe rate at which nuclei decay or disintegrate in a radioactive source, measured in
    becquerels (Bq) or decays per second
  10. 10alpha radiationIonising radiation consisting of particles comprising two protons and two neutrons
    (a helium nucleus), with a charge of +2e
  11. 11air resistanceair resistance
  12. 12ammeterA device used to measure electric current - it must be placed in series and ideally
    have zero resistance
  13. 13amount of substanceA measure of the amount of matter in moles
  14. 14AmpèreThe base SI unit of electric current, symbol A, defined as the current flowing in two parallel wires in a vacuum 1m apart such that there is an
    attractive force of 2.0 x 10-7N per metre length of wire between them
  15. 15amplitude (waves)The maximum displacement from the equilibrium position (can be positive or negative)
  16. 16angle of incidenceThe angle between the direction of travel of an incident wave and the normal at a
    boundary between two media
  17. 17angle of reflectionThe angle between the direction of travel of a reflected wave and the normal at a
    boundary between two media
  18. 18angular frequencyA quantity used in oscillatory motion - equal to the product of frequency f and 27
  19. 19angular velocityThe rate of change of angle for an object moving in a circular path - symbol c
  20. 20anionA negatively charged ion, one which is attracted to an anode
  21. 21annihilationThe complete destruction of a particle
    and its antiparticle in an interaction that releases
    energy in the form of identical photons
    anode A positively charged electrode
  22. 22antiparallel (vectors)In the same line but opposite directions
  23. 23antiparticleThe antimatter counterpart of a particle, with the opposite charge to the particle (if the
    particle has charge) and exactly the same rest mass as the particle
  24. 24antiphaseParticles oscillating completely out of step with each other (one reaches its maximum
    positive displacement as the other reaches its maximum negative displacement) are in
    antiphase
  25. 25aphelionThe furthest point from the Sun in an orbit
  26. 26Archimedes' principleThe upthrust on an object in a fluid is equal to the weight of fluid it displaces
  27. 27astronomical unitThe mean distance from the Earth to the Sun, i.e. 150 million km or 1.50 x 10' m
  28. 28atomic mass unitOne atomic mass unit (1 u) is one-twelfth the mass of a neutral carbon-12 atom
  29. 29attenuationThe decrease in the intensity of electromagnetic radiation as it passes through matter and/or space
  30. 30Avogadro constant6.02 x1023, the number of atoms in 0.012 kg (12g) of carbon-12; symbol N,
  31. 31Background radiationThe radiation emitted by the surroundings, which must be measured before radiation produced in an experiment can usefully be measured
  32. 32baryonAny hadron made with a combination of three quarks
  33. 33Base unitOne of seven units that form the building blocks of the SI measurement system
  34. 34batteryA collection of cells that transfers chemical energy into electrical energy
  35. 35becquerelA unit of activity - one becquerel is an activity of one decay per second
  36. 36beta decayA neutron in an unstable nucleus decays into a proton, an electron, and an electron antineutrino (B decay), or a proton into a neutron, a positron, and an electron neutrino (+ decay)
  37. 37beta radiationIonising radiation consisting of fast-moving electrons (ß-) or (B+) emitted
    from unstable nuclei, with a charge of -e or +e, respectively
  38. 38Big BangThe theory that at a moment in the past all the matter in the Universe was contained in a
    singularity (a single point), the beginning of space and time, that expanded rapidly outwards
  39. 39binding energyThe minimum energy required to completely separate a nucleus into its constituent
    protons and neutrons
  40. 40binding energy per nucleonThe binding energy divided by the number of protons and neutrons in the nucleus; the greater the binding energy per nucleon, the more tightly bound are the nucleons
    within the nucleus
  41. 41black bodyAn idealised object that absorbs all the electromagnetic radiation incident on it and, when in thermal equilibrium, emits a characteristic distribution of wavelengths at a specific temperature
  42. 42black holeThe remnant core of a massive star after it has gone supernova and the core has collapsed so far that in order to escape it an object would need an escape velocity greater than the speed of light, and therefore nothing, not even photons, can escape
  43. 43blue shiftThe shortening of observed wavelength that occurs when a wave source is moving
    towards the observer - in astronomy, if a galaxy is moving towards the Earth, the absorption lines in its spectrum will be blue-shifted, that is, moved towards the blue end of the spectrum
  44. 44Boltzmann constantThe molar gas constant R divided by the Avogadro constant N, a constant
    that relates the mean kinetic energy of the atoms or molecules in a gas to the gas temperature - symbol k
  45. 45Boyle's LawThe pressure of an ideal gas is inversely proportional to its volume, provided that the mass of gas and the temperature do not vary
  46. 46braking distanceDistance travelled by a vehicle from the time the brakes are applied until the vehicle stops
  47. 47breaking strengthThe stress value at the point of fracture, calculated by dividing the breaking force
    by the cross-sectional area
  48. 48brittleProperty of a material that does not show plastic deformation and deforms very little (if at all) under high stress
  49. 49Brownian motionThe continuous random motion of small particles suspended in a fluid, visible under a microscope
  50. 50capacitanceThe charge stored per unit potential difference across a capacitor
  51. 51capacitorA component that stores charge, consisting of two plates separated by an insulator (dielectric)
  52. 52carbon datingA method for determining the age of organic material, by comparing the activities, or
    the ratios, of carbon-14 to carbon-12 nuclei of the dead material of interest and similar living material
  53. 53cathodeA negatively charged electrode
  54. 54cationA positively charged ion, one which is attracted to a cathode
  55. 55cellA device that transfers chemical energy into electrical energy
  56. 56Celsius scaleA temperature scale with 100 degrees between the freezing point and the boiling point of pure water (at atmospheric pressure 1.01 x 103 Pa), 0°C and 100°C
  57. 57centre of gravityAn imaginary point at which the entire weight of an object appears to act
  58. 58centre of massA point through which any externally applied force produces straight-line motion but no rotation
  59. 59centripetal accelerationThe acceleration of any object travelling in a circular path at constant speed, which always acts towards the centre of the circle
  60. 60centripetal forceA force that keeps a body moving with a constant speed in a circular path
  61. 61chain reactionA reaction in which the neutrons from an earlier fission stage are responsible for
    further fission reactions leading to an exponential growth in the rate of the reactions
  62. 62Chandrasekhar limitThe mass of a star's core beneath which the electron degeneracy pressure is sufficient
    to prevent gravitational collapse, 1.44solar masses
  63. 63charge carrierA particle with charge that moves through a material to form an electric current. for example, an electron in a metal wire
  64. 64closed systemAn isolated system that has no interaction with its surroundings
  65. 65cloud chamberA detector of ionising radiation consisting of a chamber filled with air saturated
    with vapour at a very low temperature so that droplets of liquid condense around ionised particles left along the path of radiation
  66. 66coherenceTwo wave sources, or waves, that are coherent have a constant phase difference
  67. 67collimatorPart of a gamma camera, a honeycomb of long, thin tubes made from lead that absorbs
    any photons arriving at an angle to the axis of the tubes so that a clear picture is obtained
  68. 68cometA small, irregular body made of ice, dust, and small pieces of rock in an (often highly eccentric elliptical) orbit around the Sun - as they approach the Sun, some comets develop spectacular tails
  69. 69compressionThe decrease in length of an object when a compressive force is exerted on it
  70. 70compression (waves)A moving region in which the medium is denser or has higher pressure than the surrounding medium
  71. 71compressive deformationA change in the shape of an object due to compressive forces
  72. 72compressive forceTwo or more forces together that reduce the length or volume of an object
  73. 73conical pendulumA simple pendulum that, instead of swinging back and forth, rotates in a horizontal
    circle at constant speed
  74. 74conservation of chargeA conservation law which states that electric charge can neither be created
    nor destroyed - the total charge in any interaction must be the same before and after the interaction
  75. 75constructive interferenceSuperposition of two waves in phase so that the resultant wave has greater amplitude than the original waves
  76. 76continuous spectrumA spectrum in which all visible frequencies or wavelengths are present
    (a heated solid metal such as a lamp filament will produce this type of spectrum)
  77. 77control rodsRods made of a material whose nuclei readily absorb neutrons (commonly boron
    or cadmium), which can be moved into or out of a reactor core to ensure that exactly one slow neutron survives per fission reaction or to completely stop the fission reaction
  78. 78conventional currentA model used to describe electric current in a circuit – conventional current travels from positive to negative - it is the direction in which positive charges would travel
  79. 79coolantA substance that removes the thermal energy produced from reactions within a fission reactor
  80. 80corrected count rateThe radiation count rate measured in an experiment minus the background
    count rate
  81. 81cosmological principleThe assumption that, when viewed on a large enough scale, the Universe is homogeneous and isotropic, and the laws of physics are universal
  82. 82coulombThe derived SI unit of electrical charge, symbol C; 1 coulomb of electric charge passes
    a point in one second when there is an electric current of one ampère, IC= 1As
  83. 83Coulomb's lawAny two point charges exert an electrostatic (electrical) force on each other that is
    directly proportional to the product of their charges and inversely proportional to the square of their separation
  84. 84coupleA pair of equal and opposite forces acting on a body but not in the same straight line
  85. 85coupling gelA gel with acoustic impedance similar to that of skin smeared onto the transducer and
    the patient's skin before an ultrasound scan in order to fill air gaps and ensure that almost all the ultrasound enters the patient's body
  86. 86critical angleThe angle of incidence at the boundary between two media that will produce
    an angle of refraction of 90 °
  87. 87crystallographyA method for determining the structure of a substance by studying the
    interference patterns produced by waves passing through a crystal of the substance
  88. 88dampingAn oscillation is damped when an external force that acts on the oscillator has the
    effect of reducing the amplitude of its oscillations
  89. 89dark energyA hypothetical form of energy that fillsall of space and would explain the accelerating
    expansion of the Universe
  90. 90dark matterA hypothetical form of matter spread throughout the galaxy that neither emits nor
    absorbs light - it could explain the differences between the predicted and observed velocities of stars in galaxies
  91. 91daughter nucleusA new nucleus formed following a radioactive decay
  92. 92de Broglie equationAn equation relating the wavelength and the momentum of a particle: λ = h / p
  93. 93decay constantThe probability of decay of an individual nucleus per unit time
  94. 94densityThe mass per unit volume of a substance derived quantity A quantity that comes from a
    combination of base units
  95. 95derived unitA unit used to represent a derived quantity, such as N for force
  96. 96destructive interferenceSuperposition of two waves in antiphase so that the waves cancel each
    other out and the resultant wave has smaller amplitude than the original waves
  97. 97DiffractionThe phenomenon in which waves passing through a gap or around an obstacle spread out
  98. 98diffraction gratingA glass or plastic slide on which as many as 1000 lines in a millimetre are ruled, at
    a spacing that diffracts visible wavelengths of light
  99. 99diodeA semiconductor component that allows current only in one particular direction
  100. 100displacementThe distance travelled in a particular direction- it is a vector with magnitude and a
    direction
  101. 101displacement (waves)The distance from the equilibrium position in a particular direction displacement is a vector, so it has a positive or negative value
  102. 102drag forceThe resistive force exerted by a fluid on an object moving through it
  103. 103Doppler effectThe change in the frequency and wavelength of waves received from an object moving relative to an observer compared with what would be observed without relative motion
  104. 104Doppler equationΔλ /λ ≈ Δf / f ≈ v / c
  105. 105driving frequencyThe frequency with which the periodic driver force is applied to a system in forced oscillation
  106. 106ductileProperty of a material that has a large plastic region in a stress-strain graph, so can be drawn into wires
  107. 107eccentricityA measure of the elongation of an ellipse
  108. 108efficiencyThe ratio of useful output energy to total input energy, often expressed as a percentage
  109. 109elastic deformationA reversible change in the shape of an object due to a compressive or tensile
    force - removal of stress or force will return the object to its original shape and size (no permanent Strain)
  110. 110elastic limitThe value of stress or force beyond which elastic deformation becomes plastic
    deformation, and the material or object will no longer return to its original shape and size when the stress or force is removed
  111. 111elastic potential energyThe energy stored in an object because of its deformation
  112. 112electric chargeA physical property, symbol q or C either positive or negative, measured in coulombs, C, or as a relative charge
  113. 113electric currentThe rate of flow of charge, symbol A, measured in ampères, A; normally a flow of
    electrons in metals or a flow of ions in electrolytes
  114. 114electric field strengthThe force experienced per unit positive charge at that point
  115. 115electric potentialThe work done by an external force per unit positive charge to bring a charge from infinity to a point in an electric field – unit volt or JC-1
  116. 116electric potential differenceThe work done by an external force per unit positive charge to move a charge between two points in an electric field
  117. 117electricity meterA device that measures the electrical energy supplied in kWh to a house from the grid
  118. 118electrolyteA liquid containing ions that are free to move and so to conduct electricity
  119. 119electromagnetic spectrumThe full range of frequencies of electromagnetic waves, from gamma to radio waves
  120. 120electromagnetic waveTransverse waves with oscillating electric and magnetic field components, such as light and X-rays, that do not need a medium to propagate - they travel at a speed of 3.0 x 10 m s-1 in a vacuum
  121. 121electromotive force (e.m.f.)Defined as the energy transferred from chemical to electrical energy per unit charge
  122. 122electron degeneracy pressureA quantum-mechanical pressure created by the electrons in the core of a collapsing star due to the Pauli exclusion principle
  123. 123electron gunA device that uses a large accelerating potential difference to produce a narrow beam of
    electrons
  124. 124electronvoltA derived unit of energy used for subatomic particles and photons, defined as the
    energy transferred to or from an electron when it passes through a potential difference of I volt; 1 ev is equivalent to 1.60 x 10-19 J
  125. 125elementary chargeThe electric charge equivalent to the charge on a proton, 1.60 x 10-1 C; symbol e
  126. 126elementary particleA fundamental particle
  127. 127ellipsean elongated 'circle' with two foci
  128. 128emission line spectrumA set of specific frequencies of electromagnetic radiation, visible
    as bright lines in spectroscopy, emitted by excited atoms as their electrons make transitions between higher and lower energy states, losing the corresponding amount of energy in the form of photons as they do so - every element has a characteristic line spectrum
  129. 129energyenergy
    The capacity for doing work, measured in joules, J
  130. 130energy levelA discrete (quantised) amount of energy that an electron within an atom is permitted to possess
  131. 131equation of state of an ideal gaspV = nRT,
  132. 132equilibriumA body is in equilibrium when the net force and net moment acting on it are zero
  133. 133equilibrium position (waves)The resting position of waves or particles in an oscillation
  134. 134escape velocityThe minimum velocity at which an object has just enough energy to leave a specified
    gravitational field
  135. 135excited (an atom)Containing an electron or electrons that have absorbed energy and been boosted into a higher energy level
  136. 136expanding UniverseThe idea that the fabric of space and time is expanding in all directions and that as a result any point, in any part of the Universe, is moving away from every other point
    in the Universe, and the further the points are apart the faster their relative motion away from each other
  137. 137exponential decayA constant-ratio process in which a quantity decreases by the same factor in equal time intervals
  138. 138extensionThe increase in length of an object when a tensile force is exerted on it
  139. 139Faraday's lawThe magnitude of the induced e.m.f. is directly proportional to the rate of change of
    magnetic flux linkage
  140. 140fiducial markerA marker for a point used as a fixed basis for measurement or comparison
  141. 141filament lampAn electrical component containing a narrow filament of wire that transfers electrical energy into heat and light
  142. 142fissionA process in which a large nucleus splits into two smaller nuclei after absorbing a neutron
  143. 143Fleming's left-hand ruleA mnemonic for the direction of the force experienced by a current- carrying wire placed perpendicular to the external magnetic field: on the left hand, the first finger
    gives the direction of the external magnetic field, the second finger gives the direction of the conventional current, and the thumb gives the direction of motion (force) of the wire
  144. 144fluidA substance that can flow, including liquids and gases
  145. 145forceA push or pull on an object, measured in newtons, N
  146. 146force constantA quantity determined by dividing force by extension (or compression) for an
    object obeying Hooke's law ~ called constant of proportionality k in Hooke's law, measured in Nm-l
  147. 147force-extension graphA graph of force against extension (or compression), with the area under the graph equal to the work done on the material
  148. 148force-time graphA graph of net force against time, with the area under the graph equal to the impulse
  149. 149forced oscillationAn oscillation in which a periodic driver force is applied to an oscillator
  150. 150free oscillationThe motion of a mechanical system displaced from its equilibrium position and then allowed to oscillate without any external forces
  151. 151free electronAn electron in a metal that is not bound to an atom and is free to move - sometimes called a delocalised electron
  152. 152free fallThe motion of an object accelerating under gravity with no other force acting on it
  153. 153free-body diagramA diagram that represents the forces acting on a single object
  154. 154frequency (oscillations)The number of complete oscillations per unit time - unit Hertz (Hz)
  155. 155frequency (waves)The number of wavelengths passing a given point per unit time
  156. 156fundamental frequencyThe lowest frequency at which an object (e.g., an air column in a pipe or a string fixed at both ends) can vibrate
  157. 157fundamental mode of vibrationA vibration at the fundamental frequency
  158. 158fundamental particleA particle that has no internal structure and hence cannot be split into smaller particles
  159. 159fusionA process in which two smaller nuclei join together to form one larger nucleus
  160. 160galaxyA collection of stars and interstellar dust and gas bound together by their mutual gravitational force
  161. 161gamma radiationIonising radiation consisting of high-energy photons, with wavelengths less than about 10-13m, which travel at the speed of light
  162. 162gamma raysShort-wavelength electromagnetic waves, with wavelengths from 10-10 m to 10-16 m
  163. 163gas lawsThe laws governing the behaviour of ideal gases, like Boyle's law
  164. 164gas pressureIn stars, the pressure of the nuclei in the star's core pushing outwards and counteracting
    the gravitational force pulling the matter in the star inwards
  165. 165geostationary satelliteA satellite that remains in the same position relative to a spot on the Earth's surface, by orbiting in the direction of the Earth's rotation over the equator with a period of 24 hours
  166. 166gold-leaf electroscopeA device with a metallic stem and a gold leaf that can be used to identify and measure electric charge - a device that was historically used as a voltmeter for measuring large
    voltages
  167. 167grating equationAn equation that can be used to determine accurately the wavelength of monochromatic light sent through a diffraction grating, dsin0 = n λ
  168. 168grating spacingThe separation between adjacent lines or slits in a diffraction grating
  169. 169gravitational constant,G The constant in Newton's law of gravitation F= _ GMm / r^2 with a value determined from experiment of 6.67 × 10-11 Nkg-2 m
  170. 170gravitational fieldA field created around any object with mass, extending all the way to infinity, but diminishing as the distance from the centre of mass of the object increases
  171. 171gravitational field linesLines of force used to map the gravitational field pattern around an object having mass
  172. 172gravitational field strength, gThe gravitational force exerted per unit mass at a point within a gravitational field
  173. 173gravitational potentialThe work done per unit mass to bring an object from infinity to a point in the gravitational field - unit Jkg-I
  174. 174gravitational potential energyThe capacity for doing work as a result of an object's position in a gravitational field
  175. 175ground stateThe energy level with the most negative value possible for an electron within an atom – the most stable energy state of an electron
  176. 176HadronA particle or antiparticle that is affected by the strong nuclear force, and, if charged, by the electromagnetic force - for example, a proton
  177. 177half-lifeThe average time it takes for half the number of active nuclei in a sample of an isotope
    to decay
  178. 178harmonicA whole-number multiple of the fundamental frequency
  179. 179heavy dampingDamping that occurs when the damping forces are large and the period of the oscillations increases slightly with the rapid decrease in amplitude
  180. 180Hertzsprung-Russell diagramA graph showing the relationship between the luminosity of stars in our galaxy (on the y-axis) and their average surface temperature (on the x-axis, with temperature increasing from right to left)
  181. 181homogeneousUniform in terms of the distribution of matter across the Universe when viewed on a sufficiently large scale
  182. 182Hooke's lawThe force applied is directly proportional to the extension of the spring unless the limit of proportionality is exceeded
  183. 183Hubble constantThe gradient of a best-fit line for a plot of recessional speed against distance from Earth of other galaxies
  184. 184Hubble's lawThe recessional speed v of a galaxy is almost directly proportional to its distanced from the Earth
  185. 185hysteresis loopA loop-shaped plot obtained when, for example, loading and unloading a material produce different deformations
  186. 186ideal gasA model of a gas including assumptions that simplify the behaviour of real gases
  187. 187impedance matching (or acoustic matching)The use of two substances with similar acoustic impedance to minimise reflection of ultrasound at the boundary between them
  188. 188impulseThe area under a force-time graph - the product of force and the time for which the
    force acts
  189. 189in phaseParticles oscillating perfectly in time with each other (reaching their maximum positive
    displacement at the same time) are in phase
  190. 190inelastic collisionA collision in which kinetic energy is transferred to other forms, e.g. heat induced fission Nuclear fission occurring when a nucleus becomes unstable on absorbing another particle (such as a neutron)
  191. 191inflationA phase of astonishing acceleration of the expansion of the Universe thought to have occurred 10-35s after the Big Bang
  192. 192infrared wavesElectromagnetic waves, with wavelengths from 10-3 m to 7x 10-7 m
  193. 193instantaneous speedThe speed at the moment it is measured - speed over an infinitesimal interval
    of time
  194. 194intensity (waves)The radiant power passing through a surface per unit area -_ unit Wm-2
  195. 195intensity reflection coefficientThe ratio of reflected intensity over incident intensity for ultrasound incident at a boundary
  196. 196interferenceSuperposition of two progressive waves from coherent sources to produce a resultant
    wave with a displacement equal to the sum of the individual displacements from the two waves
  197. 197interference patternA pattern of constructive and destructive interference formed as waves overlap
  198. 198internal energyThe sum of the randomly distributed kinetic and potential energies of the atoms, ions, or molecules within the substance
  199. 199internal resistanceThe resistance of a source of e.m.f. (e.g a cell) due to its construction, which causes a loss in energy/voltage as the charge passes through the source, symbol r, SI unit ohm
  200. 200ionAn atom that has either lost or gained electrons and so has a net charge

Information

Description
physics A level Flashcards on Defenitions (1), created by lizabeth rawson on 05/04/2022.
Created by
lizabeth rawson
Views
2
Rating

Feedback

What is it about?

What do you think of the new look?

How do you like it?