# OCR Physics B (Advancing Physics) Yr 2 Glossary

Fully inclusive collection of the definitions for the 2nd Yr. collected from the textbook, revision guide and checked against past mark schemes.

0.0 / 5

- Created by: paper-weight
- Created on: 27-05-18 13:25

Absolute Luminosity

The brightness a star world have at a standard distance of 10 parsec

1 of 134

Absolute Zero

The zero of the thermodynamic temperature at 0K or -273 degrees C. Particles of ideal gas have no energy at this temperature

2 of 134

Absorbed Dose

The number of joules of energy absorbed from ionizing radiation per kilogram of tissue (Unit = grays, Gy)

3 of 134

Activation Energy, E

The minimum energy required for a given process to occur

4 of 134

Activity

The number of nuclei in a radioactive source that decay per second (Unit= Bq)

5 of 134

Alternating Current

A current, alternating sinusoidally, produced by an alternating p.d. in a circuit.

6 of 134

Amplitude

The maximum displacement of an oscillator from its equilibrium position

7 of 134

Angular Frequency

The angle moved per second (Unit= radians)

8 of 134

Anti-Particle

The counterpart to a particle which has the same rest energy and is equal but oppositely charged

9 of 134

Armature

The rotating part of an electric motor, which carries the coil

10 of 134

Astronomical Unit

The mean distance between the Earth and Sun

11 of 134

Atomic mass unit, u

One twelfth of the mass of an atom of carbon-12

12 of 134

Avogadro constant

The number of particles in a mole of substance

13 of 134

Back e.m.f.

An e.m.f. generated by a spinning motor that opposes the p.d. driving the motor and limits its speed

14 of 134

Background radiation

Radiation that is detectable from the environment which is not involved in an experiment

15 of 134

Big Bang Theory

The probable origin of the universe in a very hot, dense state from which it has expanded and cooled

16 of 134

Binding Energy

The energy required to break a nucleus into its individual nucleons

17 of 134

Boltzmann Factor

The proportion of particles in a substance which have energy above the activation energy required for a given reaction

18 of 134

Boyle's Law

The pressure of an ideal gas is inversely proportional to volume, at a constant temperature. pV=constant

19 of 134

Capacitance

The charge separated per volt of a capacitor

20 of 134

Chain reaction

A reaction is which the products of a reaction go on to start one or more further reactions

21 of 134

Charles' Law

The volume of an ideal gas is proportional to the temperature, at a constant pressure. V/T=constant

22 of 134

Commutator

A switching mechanism that reverses the connections to the coil of an electric motor to maintain its direction of motion

23 of 134

Cosmetic background radiation

Microwave radiation that permeates the entire universe and was created during the Big Bang. Its wavelength has increased due to being stretched over time as the universe expands.

24 of 134

Cosmological Red-Shift

The red shift of light from very distant galaxies that is caused by the wavelength of the light being stretched as the universe has expanded.

25 of 134

Coulomb's Law

The force between two charged spheres is directly proportional to each of the charges and inversley proportional to the square of the distance between the centers of the charges.

26 of 134

Count Rate

The number of particles of ionizing radiation emitted from a radioactive sample that are detected by the measuring system per second. It is less than, but proportional to, the activity.

27 of 134

Critical damping

Reduction of simple harmonic motion in which the oscillator stops at the equilibrium position without completing a cycle

28 of 134

Damping

The action of forces such as friction to reduce the amplitude of an oscillator due to energy loss from the system

29 of 134

Decay constant

The probability that a nucleus will decay during a time interval of 1 second (Unit= S^-1)

30 of 134

Diffusion

The slow intermingling of gases or liquids, due purely to the random motion of the particles

31 of 134

Doppler Shift

A change in observed wavelength due the relative motion of source and observer

32 of 134

Effective Dose

The product of the absorbed dose and the quality factor of the ionizing radiation that has been absorbed. (Unit= sieverts, Sv)

33 of 134

Dynamo

An older term for an electrical generator, now sometimes used to refer to a d.c.generator

34 of 134

Eddy Current

Electrical currents induced in the core of a transformer by the changing flux linkage within the core. The currents oppose the change in flux that caused them causing work to be done and so energy loss in the core.

35 of 134

Einstein's 1st Postulate

Physical behavior cannot depend on any 'absolute velocity'. Physical laws must take the same form for all observers, no matter what their state of uniform motion in a straight line

36 of 134

Einstein's 2nd Postulate

The speed of light is a universal constant.

37 of 134

Electric Field

A region surrounding an electrical charge where another electrical charge would experience a force

38 of 134

Electric Field Strength

The magnitude and direction of the force per unit charge at any given point in an electric field

39 of 134

Electrical Potential

The potential electrical energy per unit of charge in and electric field given as the work done to move the unit of charge from infinity to that postition

40 of 134

Electrical Potential Energy

The potential energy of a charge in an electric field given as the work done when moving the charge from an infinite distance to its position within the electric field

41 of 134

Electrical permittivity of free space

A fundamental electrical property of free space

42 of 134

Energy

A measure of the capacity of a body or system to do work

43 of 134

Equilibrium Position

The position of an oscillator on which no net force is acting

44 of 134

Equipotential Surface

A continuous surface joining points of the same potential in a three dimensional field

45 of 134

Exponential change

Difference in values has a constant ratio property where the value will change by the same ratio in equal time

46 of 134

Faraday's Law

The induced e.m.f. will produce a current which opposes the rate of change of flux linkage responsible for the induction (eddy currents)

47 of 134

1st Law of Thermodynamics

The change in internal energy of a system is the sum of the work done on the system and the energy transferred thermally into it

48 of 134

Flux Linkage

The product of the number of turns of wire in a coil and the flux that is induced per coil

49 of 134

Forced oscillation

An oscillation driven by the action of a periodic driving force

50 of 134

Free oscillation

An oscillation due to the action of a restoring force without any dampening or driving forces

51 of 134

Generator

An electromagnetic machine that uses rotation to produce the flux changes needed to induce an e.m.f.

52 of 134

Gluon

The exchange particle that mediates the strong nuclear force

53 of 134

Gravitational Field

The region surrounding a mass where another mass would experience a force

54 of 134

Gravitational Field Strength

The magnitude and direction of the force per unit mass at a given point in a gravitational field

55 of 134

Gravitational potential

The gravitational potential energy per unit mass at a given position in a gravitational given as the work done to move the unit mass from infinity to its position in the gravitational field

56 of 134

Gravitational Potential Energy

The work done to move a mass from infinity to its position in the gravitational field

57 of 134

Hadron

A particle composed of two or three quarks

58 of 134

Half-life

The time required for the number of nuclei in a sample to reach half the original value

59 of 134

Half-thickness

The thickness of absorber needed to halve the number of photons that can pass through on average

60 of 134

Heavy Dampening

Reduction of simple harmonic motion in which the oscillator returns to the equilibrium position much more slowly than a lightly of critically damped oscillator

61 of 134

Hertzsprung-Russell diagram

A logarithmic plot of the luminosity of stars against their surface temparature

62 of 134

Hubble's Law

The recessional velocity at which a galaxy is moving away from the earth is proportional to its distance from earth. Provides evidence for the big bang since all galaxies must have started at a single point

63 of 134

Ideal gas

A gas in which there is no intermolecular interaction and the molecules occupy negligible volume

64 of 134

Induction

The creation of an e.m.f. across a circuit when the magnetic flux in the circuit is changed

65 of 134

Internal energy

The energy within a system allowing it to do work or transfer energy thermally / The sum of the kinetic and potential energy of the particles within a system

66 of 134

Ionic bond

A strong bond between ions due electrostatic attraction, bond are localized and directional

67 of 134

Ionisation

Removal of an electron from, or addition of an electron to, an uncharged atom or molecule resulting in the formation of an ion

68 of 134

Ionisation energy

The energy that must be supplied to a neutral atom or molecule in order to ionize it

69 of 134

Ionized Gas

A gas in which some atoms have lost electrons to become positive ions

70 of 134

Isotope

Forms of the same element where they have the same proton number but different neutron numbers

71 of 134

Iteration

A repeat of a mathematical operation

72 of 134

Laminations

Insulating between thin layers of core in a transformer to reduce the area that eddy currents can form over which reduces the size of the currents which helps to reduce the energy lost when by the currents opposing the changing flux linkage

73 of 134

Lenz's Law

The direction of an induced e.m.f. is always such as to act against the change that caused the induced e.m.f.

74 of 134

Lepton

A group of fundamental particles (e.g. electrons and neutrinos)

75 of 134

Lidar

Light detection and ranging. Finding the distance to a remote object using the delay in return of a pulse of light.

76 of 134

Light Dampening

Reduction of simple harmonic motion in which the maximum displacement of the oscillator is reduced in each oscillation but the time period of the oscillation is roughly constant

77 of 134

Light-year

The distance travelled by light in 1 year

78 of 134

Magnetic circuit

Analogous to an electric circuit, an arrangment whereby flux between magnetic poles is carried by a suitable magnetic material between poles

79 of 134

Magnetic Field

A region surrounding a magnet in which a moving charge would experience a force

80 of 134

Magnetic Flux Density

A measure of the strength of a magnetic field (Unit= Tesla, T)

81 of 134

Mass Defect

The difference between the mass of a nucleus and the total mass of the individual nucleons

82 of 134

Metallic Bond

A strong bond between the positive ions of metal atoms which are held together in a lattice by a sea of delocalized electrons, bonds are non-directional and delocalized

83 of 134

Moderator

A material (often water) used to slow down neutrons in a fission reactor to increase the probability of successful further reactions due to collisions

84 of 134

Molar mass

The mass of 1 mole of a substance

85 of 134

Natural Frequency

The frequency of a free oscillator

86 of 134

Neutrino

An uncharged lepton of insignificant mass, very low interaction

87 of 134

Neutron

An uncharged hadron composed of 2 down an 1 up quark, udd

88 of 134

Nuclear Fission

The splitting of a heavy nucleus to form lighter nuclei

89 of 134

Nuclear Fusion

The fusion of two light nuclei to form a heavier nucleus

90 of 134

Nucleon

Particles found in the nucleus of an atom (protons and neutrons)

91 of 134

Nucleon number

The number of protons and neutrons in the nucleus of an atom

92 of 134

Nucleus

The central, relatively massive core of an atom

93 of 134

Overdampening

Reduction of simple harmonic motion in which the oscillator stops at the equilibrium position without completing a cycle but in much longer time that critical dampening

94 of 134

Parallax

The apparent shift in position of near objects against the background of further objects when the observer moves

95 of 134

Parsec, pc

The distance at which a star would have a parallax angle from earth of 1

96 of 134

Particle Accelerator

A device using electrical fields to accelerate charge particles

97 of 134

Pauli exclusion principle

No 2 identical fermions (electrons, protons and neutrons) can share the same quantum state: e.g. opposite spin on electrons. Explains why the matter does not collapse into itself.

98 of 134

Pendulum

A mass (bob) on the end of a spring that can demonstrate simple harmonic motion

99 of 134

Permeance

A measure of how easily flux lines are set up in a magnetic circuit.

100 of 134

Permeability

A measure of the number of flux lines that are set up per unit area for a given material and e.m.f.

101 of 134

Positron

The antiparticle counterpart of an electron

102 of 134

Pressure Law

The pressure in an ideal gas is proportional to the temperature for a constant volume. P/T= constant

103 of 134

Proton

A positively charged hadron composed of 2 up and 1 down quark, uud

104 of 134

Proton Number

The number of protons in the nucleus of an atom

105 of 134

Quark

The fundamental particle that makes up hadrons

106 of 134

Radar

Radio detection and ranging. Finding the distance to a remote object using the delay in return of a pulse of electromagnetic radiation.

107 of 134

Radioactive decay

The release of particles by the nuclei of atoms of unstable elements

108 of 134

Radioactivity

The phenomenon whereby unstable nuclei change, emitting ionizing radiation

109 of 134

Random Walk

The random movement of a single molecules during diffusion due to repeated collisions with other molecules. Total displacement will be the square route of N steps of constant distance

110 of 134

Random

A situation in which an event occurs by chance and is not effected by any external factors (e.g. temperature, pressure or other events)

111 of 134

Red-shift

The shift of spectral lines towards the red end of the colour spectrum caused by the doppler shift of light from galaxies which are moving away from the earth

112 of 134

Resonance

The effect produced when the driving frequency is close to or matches the natural frequency of an oscillator resulting in larger amplitude oscillations

113 of 134

Restoring force

The force acting towards the equilibrium position of an oscillator which causes it to accelerate in the opposite direction to the motion of the oscillator

114 of 134

Risk of radiation

The probability of developing cancer due to exposure to ionizing radiation per sievert of effective dose

115 of 134

Root mean square speed

The square root of the mean square speed. (all speeds squared, mean value taken, mean value rooted)

116 of 134

Rotor

The rotating part of an electric motor or generator

117 of 134

Scattering

The deflection of accelerated particles due to interaction with nuclei or with other particle

118 of 134

2nd Law of Thermodynamics

The total entropy never decreases. (Molecular collisions always redistribute energy not lose it)

119 of 134

Simple Harmonic Motion

When the acceleration of a system at any instant is proportional to its displacement from the equilibrium position at that instant and acts in the opposite direction to this displacement towards the equilibrium position

120 of 134

Solenoid

A long, current carrying coil which acts as an electromagnet

121 of 134

space-time diagram

A representation of the paths of objects moving through space and time. Time on the y-axis (seconds, s) and distance on the x-axis (light-seconds, x/c)

122 of 134

Specific Thermal Capacity, c

The increase in internal energy required to raise the temperature of 1kg of andy given material by 1K

123 of 134

Standard Candle

A star of known absolute luminosity that can be used as a comparative measure for other stars

124 of 134

Statistical mechanics

The study of how the behavior of matter and energy is governed by statistics dealing with random distributions

125 of 134

Stator

The stationary part of an electric motor or generator

126 of 134

Strong interaction

A fundamental force that holds nuclei together

127 of 134

Strong nuclear force

The force that holds nuclei together in the nucleus

128 of 134

Tesla

The unit for flux density, the force per unit current per length of a conductor perpendicular to the lines of magnetic flux

129 of 134

Time constant,

The product of RC, the time for the charge on a capacitor to reduce to 37% of its original value

130 of 134

Time period

The time for one complete oscillation of an oscillator

131 of 134

Transformer

An electromagnetic machine that transforms voltages by inducing e.m.f. without physical movement

132 of 134

Van der Waal forces

Weak intermolecular forces between molecules caused by the interaction of instantaneously induced dipoles of the molecules

133 of 134

Worldline

A line on a space time diagram representing the path of an object through space and time. World lines for electromagnetic pulses are at 45 degrees

134 of 134

## Other cards in this set

### Card 2

#### Front

The zero of the thermodynamic temperature at 0K or -273 degrees C. Particles of ideal gas have no energy at this temperature

#### Back

Absolute Zero

### Card 3

#### Front

The number of joules of energy absorbed from ionizing radiation per kilogram of tissue (Unit = grays, Gy)

#### Back

### Card 4

#### Front

The minimum energy required for a given process to occur

#### Back

### Card 5

#### Front

The number of nuclei in a radioactive source that decay per second (Unit= Bq)

#### Back

## Similar Physics resources:

0.0 / 5

0.0 / 5

0.0 / 5

0.0 / 5

0.0 / 5

## Comments

No comments have yet been made