Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

13B > Definitions > Flashcards

Definitions Flashcards

1
Q

Effort

A

the force applied to a machine to make it move

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

elastic collision

A

an elastic collision is one in which the total kinetic energy after the collision is equal to the total kinetic energy before the collision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

elasticity

A

property of a solid that enables it to regain its shape after it has been deformed or distorted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

elastic limit

A

point beyond which a wire is permanently stretched

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

electrical conductor

A

an object that can conduct electricity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

electrically insulating materials

A

an electrical insulator is a material that cannot conduct electricity; a thermal insulator is a material that is a poor conductor of heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

electric field strength, E

A

at a point in the electric field, is the force per unit charge on a small positively charged object at a point in the field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

electric potential, V

A

at a point in the electric field is the work done per unit charge on a small positively charged object to move it from infinity to that point in the field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

electrolysis

A

process of electrical conduction in a solution or molten compound due to ions moving to the oppositely charged electrode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

electrolyte

A

a solution or molten compound that conducts electricity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

electromagnetic induction

A

the generation of an emf when the magnetic flux linkage through a coil changes or a conductor cuts across magnetic field lines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

electromagnetic radiation

A

an electric and magnetic wavepacket or photon that can travel through free space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

electromagnetic wave

A

an electric and magnetic wavepacket or photon that can travel through free space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

electromotive force (emf)

A

the amount of electrical energy per unit charge produced inside a source of electrical energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

electron

A

a lepton with rest mass 9.11x10e-31 kg and electric charge -1.60x10e-19 C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

electron capture

A

a proton-rich nucleus captures an inner-shell electron to cause a proton in the nucleus to change into a neutron. An electron neutrino is emitted by the nucleus. An X-Ray photon is subsequently emitted by the atom when the inner shell vacancy is filled.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

electron volt

A

amount of energy equal to 1.6x10e-19 J defined as the work done when an electron is moved through a pd of 1V

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

endoscope

A

optical fibre device used to see inside cavities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

energy

A

the capacity to do work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

energy levels

A

the energy of an electron in an electron shell of an atom or the allowed energies of a nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

equilibrium

A

state of an object when at rest or in uniform motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

equipotential

A

a line or surface in a field along which the electric or gravitational potential is constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

escape velocity

A

the minimum velocity an object must be given to escape from the planet when projected vertically from the surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

excitation

A

process in which an atom absorbs energy without becoming ionized as a result of an electron inside an atom moving from an inner shell to an outer shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

excited state

A

an atom which is not in its ground state (i.e., its lowest ground energy state)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

explosion

A

when two objects fly apart and the two objects carry away at opposite and equal momentums

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

exponential change

A

exponential change happens when the change of a quantity is proportional to the quantity itself. For an exponential decrease of a quantity x, (dx/dt = -the decay constant multiplied by x). The solution to this equation is x = x0 multiplies by e to the power of (-the decay constant x t) where x0 is an initial value of x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Faraday’s Law of electromagnetic induction

A

the induced emf in a circuit is equal to the rate of change of magnetic flux linkage through the circuit. For a changing magnetic field in a fixed coil of area A and turns N, the induced emf = -NA(change in B/ change in t)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

field line

A

the direction of a line of force indicates the direction of the force. An electric field line is the path followed by a free positive test charge. The gravitational field lines of a single mass point towards that mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

first harmonic

A

pattern of stationary waves on a string when it vibrates at its lowest possible frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

fission

A

the splitting of a 92U nucleus or a 94Pu nucleus into two approximately equal fragments. Induced fission is fission caused by an incoming neutron colliding with a 92U nucleus or a 94Pu nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

fission neutrons

A

neutrons released when a nucleus undergoes fission and which may collide with nuclei to cause further fission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Fleming’s left hand rule

A

rule that relates the directions of force, magnetic field and current on a current carrying conductor in a magnetic field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Fleming’s right hand rule

A

rule that relates the directions of the induced current, magnetic field and velocity of the conductor when the conductor cuts across magnetic field lines and an emf if induced in it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

fluorescence

A

glow of light from a substance exposed to ultraviolet radiation; the atoms de-excite in stages and emit visible photons in the process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Beta plus radiation

A

Positrons (B+) emmited by unstable proton-rich nuclei (ie nuclei with a neutron/proton ratio smaller than for stable nuclei). Positrons emitted in solids or liquids travel no further than about 2mm before they are annihilated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Absolute scale

A

Temperature scale in kelvins (K) defined in terms of absolute zero, 0K, and the triple point of water, 273.16K, which is the temperature at which ice, water and water vapour are in thermal equilibrium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Absolute zero

A

The lowest possible temperature, the temperature at which an object has minimum internal energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Absolute temperature T

A

…in kelvin = temperature in degrees C +273(.15)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Acceleration

A

Change of velocity per unit time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Acceleration of free fall

A

Acceleration of an object acted on only by the force of gravity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Activity A

A

…of a radioactive isotope, the number of nuclei of the isotope that disintegrate per second. The unit of activity is the becquerel (Bq), equal to 1 disintegration per second.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Alpha decay

A

Change in an unstable nucleus when it emits an alpha particle which is a particle consisting of two protons and two neutrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Alpha radiation

A

Particles that are each composed of two protons and two neutrons. An alpha particle is emitted by a heavy unstable nucleus which is then less unstable as a result. Alpha radiation is easily absorbed by paper, has a range in air of no more than a few centimetres and is more ionising than beta or gamma radiation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Amplitude

A

The maximum displacement from equilibrium of an oscillating object. For a transverse wave, it is the distance from the middle to the peak of the wave.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Angular displacement

A

The angle an object in circular motion turns through. If its time period is T and its frequency is f, its angular displacement in time t, in radians = 2pift = 2pi*t/T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Angular speed (omega)

A

The rate of change of angular displacement of an object in circular (or orbital or spinning) motion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Angular frequency (omega)

A

For an object oscillating at frequency f in simple harmonic motion, its angular frequency = 2pif

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Annihilation

A

When a particle and its antiparticle meet, they destroy each other and become radiation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Antibaryon

A

A hadron consisting of 3 antiquarks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Antimatter

A

Antiparticles that each have the same rest mass and, if charged, have equal and opposite charge to the corresponding particle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Antimuon

A

The antiparticle of the muon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Antineutrino

A

The antiparticle of the neutrino.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Antinode

A

Fixed point in a stationary wave pattern where the amplitude is a maximum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Antiparticle

A

There is an antiparticle for every type of particle. A particle and its corresponding antiparticle have equal rest mass and, if charged, equal and opposite charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Antiquark

A

Antiparticle of a quark.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Atomic mass unit (u)

A

Correctly referred to as the unified atomic mass constant; 1/12th of the mass of an atom of the carbon isotope 12C6, equal to 1.661x10^-27 kg.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Atomic number (Z)

A

…of an atom of an element is the number of protons in the nucleus of the atom. It is also the order number of the element in the Periodic Table.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Avogadro constant (Na)

A

The number of atoms in 12g of the carbon isotope 12C6. Na is used to define the mole. Its value is 6.02x10^23 mol^-1.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Back EMF

A

EMF induced in the spinning coil of an electric motor or in any coil in which the current is changing (e.g. the primary coil of a transformer). A back EMF acts against the change of applied pd.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Background radiation

A

Radiation due to naturally occurring radioactive substances in the environment (e.g. in the ground or in building materials or elsewhere). Background radiation is also caused by cosmic radiation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Baryon

A

A hadron consisting of three quarks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Base units

A

The units that define the SI system (e.g. the metre, the kilogram, the second, the ampere).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Beta decay

A

Change in a nucleus when a neutron changes into a proton and an electron and an antineutrino are emitted if the nucleus is neutron-rich or a proton changes into a neutron and a positron and a neutrino are emitted if the nucleus is proton-rich.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

force

A

rate of change of momentum

mass x acceleration for fixed mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

forced vibrations

A

vibrations (oscillations) of a system subjected to an external periodic force.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

free-body force diagram

A

a diagram of an object showing only the forces acting on the object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

free electrons

A

electrons in a conductor that move about freely inside the metal because they are not attached to a particular atom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

free vibrations

A

vibrations (oscillations) where there is no damping and no periodic force acting on the system, so the amplitude of the oscillations is constant.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

frequency

A

of an oscillating object is the number of cycles of oscillations per second.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

friction

A

force opposing the motion of a surface that moves or tries to move across another surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

fundamental mode of vibration

A

pattern of stationary waves on a string when it vibrates at its lowest possible frequency.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

fusion (nuclear)

A

the fusing together of light nuclei to form a heavier nucleus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

fusion (thermal)

A

the fusing together of metals by melting them together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

gamma radiation

A

electromagnetic radiation emitted by an unstable nucleus when it becomes more stable. See pair production.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

geostationary satellite

A

a satellite that stays above the same point in the earth’s equator as it orbits the earth because it’s orbit is exactly 24 hours and it orbits in the same direction as the earth’s direction of rotation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

gold leaf electroscope

A

a device used to detect electric charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

gravitational constant (G)

A

the constant of proportionality in Newton’s law of gravitation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

gravitational field

A

the region surrounding an object in which it exerts a gravitational force on any other object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

gravitational field strength (g)

A

the force per unit mass on a small mass placed in the field.

  1. g = F/m, where F is the gravitational force on a small mass m.
  2. at distance r from a point mass M, and at or beyond the surface of a sphere of mass M, g = gM/r^2 where r is the distance to the centre.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

gravitational force

A

an attractive force that acts equally on any two objects due to their mass.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

gravitational potential (V)

A

at a point in a gravitational field is the work done per unit mass to move a small object from infinity to that point. At distance r from the centre of a spherical object of mass M,
V = -GM/r

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

gravitational potential energy

A

at a point in a gravitational field is the work done to move a small object from infinity to that point. the change of GPE of a mass m moved through height h near the earth’s surface. ∆Ep = mg∆h

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

grid system

A

the network of transformers and cables that is used to distribute electrical power from power stations to users.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

ground state

A

the lowest energy state of an atom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

hadron

A

particles and antiparticles that can interact through the strong interaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

half-life

A

the time taken for the mass of a radioactive isotope to decrease to half of the initial mass or for its activity to halve. This is the same as the time taken for the number of nuclei of the isotope to decrease to half the initial number.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Hall probe

A

a device used to measure magnetic flux density.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

heat (Q)

A

energy transfer due to difference of temperature.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

heat capacity

A

the energy needed to raise the temperature of an object by 1K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

heat exchanger

A

a steel vessel containing pipes through which hot coolant in a sealed circuit is pumped, causing water passing through the steel vessel in sperate pipes to turn to steam which is used to drive turbines.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

Hooke’s law

A

the extension of a spring is proportional to the force needed to extend it up to a limit referred to as its limit of proportionality.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

ideal gas

A

a gas under conditions such that it obeys Boyle’s law.

94
Q

ideal gas equation

A

pV = nRT, where p is the gas pressure, V is the gas volume, n is the number of moles of gas, T is the absolute temperature and R is the molar gas constant.

95
Q

impulse

A

of a different acting on an object, force x time for which the force acts.

96
Q

induced emf

A

the generation of an emf when the magnetic flux linkage through a coil changes or a conductor cuts across magnetic field lines.

97
Q

induced fission

A

fission caused by an incoming neutron colliding with a
235 235
92 U nucleus or a 94 Pu nucleus causing it to split into two approximately equal fragments.

98
Q

inertia

A

resistance of an object to change its motion.

99
Q

Integration

A

Mathematical process of finding the area under the curve from its mathematical equation

100
Q

Intensity of radiation

A

At a surface is the radiation energy per second per unit area at normal incidence to the surface

101
Q

Interference

A

Formation of points of cancellation and reinforcement where two coherent waves pass through each other

102
Q

Internal energy

A

Of an object is the sum of the random distribution of the kinetic and potential energy of its molecules

103
Q

Internal resistance

A

Resistance inside a source of electrical energy; the loss of pd per unit current in the source when current passes through it

104
Q

Ion

A

A charged atom

105
Q

Ionisation

A

Process of creating ions

106
Q

Ionising radiation

A

Radiation that produces ions in the substance it passes through. It destroys cell membranes and damages vital molecules such as DNA directly or indirectly by creating ‘free radical’ ions which reacts with vital molecules

107
Q

Isotopes

A

Of an element or atoms which have the same number of protons in its nucleus but different numbers of neutrons

108
Q

Kaon

A

A meson that consists of a strange quark or anti-quark and another quark or anti-quark

109
Q

Kepler’s third law

A

For any planet, the cube of its mean radius of orbit (r) is directly proportional to the square of its time period (T)

110
Q

Kinetic energy

A

The energy of a moving object due to its motion

E=mv^2

111
Q

Kinetic theory of a gas

A

1) Assumptions; A glass consists of identical point molecules which do not attract one another.The molecules are in continual random motion colliding elastically with each other and with the container
2) pV=1/3Nmc^2

p-pressure
V-volume of container
N - number of molecules 
m-mass of each molecule
c^2- The mean square speed of the gas molecule
112
Q

Laser

A

Device that produces a parallel coherent beam of monochromatic light

113
Q

Latent heat of fusion

A

The energy needed to change the state of the solid to a liquid without change of temperature

114
Q

Latent heat of vaporisation

A

The energy needed to change the state of a liquid to a vapour without change of temperature

115
Q

Lenz’s law

A

When a current is induced by an electromagnetic induction the direction of the induced current is always such as to oppose the change that causes the current

116
Q

Lepton

A

Electrons, muons, neutrinos, and their antiparticles are classified as leptons because they cannot interact through the strong interaction. They interact through the weak interaction and, in the case of electrons and positrons, through the electromagnetic interaction

117
Q

Lepton number

A

Electron number is assigned to every lepton and antilepton, On the basis that the total lepton number for each branch of the lepton family is always conserved

118
Q

Light dependent resistor (LDR)

A

Resistor which is designed to have a resistance that changes with the light intensity

119
Q

Limit of proportionality

A

The limits beyond which when a wire or a spring is stretched its extension is no longer proportional to the force that stretches it

120
Q

control rods

A

rods made of a neutron-absorbing substance such as cadmium or boron that are moved in or out of the core of a nuclear reactor to control the rate of fission events in the reactor.

121
Q

coolant

A

a fluid that is used to prevent a machine from becoming dangerously hot. The coolant of a nuclear reactor is pumped through the core of the reactor to transfer thermal energy from the core to a heat exchanger.

122
Q

Coulomb’s law of force

A

for two points Q1 and Q2 at distance apart r, the force F between the two charges is given by the equation F = Q1Q2/4πɛ0r^2, where ɛ0 is the permittivity of free space.

123
Q

drag force

A

the force of fluid resistance on an object moving through the fluid.

124
Q

couple

A

pair of equal and opposite forces acting on a body but not along the same line.

125
Q

critical angle

A

the angle of incidence of a light ray must exceed the critical angle for total internal reflection to occur.

126
Q

critical mass

A

the minimum mass of the fissile isotope (e.g., the uranium isotope 235 92 U) in a nuclear reactor necessary to produce a chain reaction. If the mass of the fissile isotope in the reactor is less than the critical mass, a chain reaction does not occur because too many fission neutrons escape from the reactor or are absorbed without fission.

127
Q

critical temperature of a superconducting material

A

temperature at and below which its resistivity is zero.

128
Q

cycle

A

interval for a vibrating particle (or a wave) from a certain displacement and velocity to the next time the particle (or wave) that has the same displacement and velocity.

129
Q

damped oscillations

A

oscillations that reduce in amplitude due to the presence of resistive forces such as friction and drag.

  1. For a lightly damped system, the amplitude of oscillations decreases gradually.
  2. For a heavily damped system displaced from equilibrium then released, the system slowly returns to equilibrium without oscillating.
  3. For a critically damped system, the system returns to equilibrium in the least possible time without oscillating.
130
Q

de Broglie wavelength

A

a particle of matter has a wave-like nature which means that it can behave as a wave. For example, electrons directed at a thin crystal are diffracted by the crystal. The de Broglie wavelength, λ, of a matter particle depends on its momentum, p, in accordance with de Broglie’s equation λ = h/p = h/mv, where h is the Planck constant.

131
Q

decay constant λ

A

the probability of an individual nucleus decaying per second.

132
Q

decay curve

A

an exponential decrease curve showing how the mass or activity of a radioactive isotope decreases with time.

133
Q

de-excitation

A

process in which an atom loses energy by photon emission, as a result of an electron inside an atom moving from an outer shell to an inner shell or in which an excited nucleus emits a gamma photon.

134
Q

density of a substance

A

mass per unit volume of the substance.

135
Q

dielectric

A

material that increases the capacity of a parallel-plate capacitor to store charge when placed between the plates of a capacitor. Polythene and waxed paper are examples of dielectrics.

136
Q

dielectric constant

A

See relative permittivity.

137
Q

differentiation

A

mathematical process of finding the gradient of a line from its equation.

138
Q

diffraction

A

the spreading of waves when they pass through a gap or round an obstacle. X-ray diffraction is used to determine the structure of crystals, metals and long molecules. Electron diffraction is used to probe the structure of materials. High-energy electron scattering is used to determine the diameter of the nucleus.

139
Q

diffraction grating

A

a plate with many closely ruled parallel slits on it.

140
Q

dispersion

A

splitting of a beam of white light by a glass prism into colours.

141
Q

displacement

A

distance in a given direction.

142
Q

dissipative forces

A

forces that transfer energy which is wasted.

143
Q

dose equivalent

A

a comparative measure of the effect of each type of ionising radiation, defined as the energy that would need to be absorbed per unit mass of matter from 270k of X-radiation to have the same effect as a certain dose of the ionising radiation. The unit of dose equivalent is the sievert (Sv).

144
Q

drag force

A

the force of fluid resistance on an object moving through the fluid.

145
Q

ductile

A

stretches easily without breaking.

146
Q

dynamo rule

A

See Fleming’s right-hand rule.

147
Q

eddy currents

A

induced currents in the metal parts of ac machines.

148
Q

efficiency

A

the ratio of useful energy transferred (or the useful work done) by a machine or device to the energy supplied to it.

149
Q

scalar

A

physical quantity with magnitude only

150
Q

semiconductor

A

substance in which the number of charge carriers increases when the temperature is raised

151
Q

SI system

A

scientific system of units

152
Q

simple electric motor

A

electric motor with an armature consisting of a single coil of insulated wire

153
Q

simple harmonic motion

A

motion of an object where the acceleration towards equilibrium position is proportional to the displacement of the object from equilibrium and in the opposite direction

154
Q

sinusoidal curve

A

any curve with the same shape as a sine wave (or cosine wave)

155
Q

specific heat capacity c

A

of a substance is the energy needed to raise the temperature of 1kg of the substance by 1K without changing the state (Q = mcΔT)

156
Q

specific charge

A

value of unit charge per unit mass for a charged particle

157
Q

specific latent heat of fusion

A

of a substance is the energy needed to change the state of 1kg of solid to liquid without a change in temperature (Q = ml)

158
Q

specific latent heat of vaporisation

A

of a substance is the energy needed to change the state of 1kg of liquid to vapour without a change in temperature (Q = ml)

159
Q

spectrometer

A

instrument used to measure wavelegths of light very accurately

160
Q

speed

A

change in distance per unit time

161
Q

stationary waves

A

wave pattern with nodes and antinodes formed when two (or more) progressive waves

162
Q

stiffness constant

A

force per unit extension needed to extend a spring or wire

163
Q

stopping distance

A

sum of the thinking and breaking distances

164
Q

strain

A

extension per unit length of a solid when deformed

165
Q

strangeness number

A

number assigned to every particle and antiparticle on the basis that strangeness is conserved in strong interactions, but not always in a weak reaction or decay

166
Q

stress

A

force per unit cross-sectional, perpendicular area in a solid

167
Q

strong interaction

A

interaction between two hadrons

168
Q

strong nuclear force

A

force that holds the nucleons together; attractive between 2 to 3 fm, repulsive below 0.5 fm

169
Q

sublimation

A

change of state when a solid changes directly into vapour

170
Q

superconductor

A

material that has zero electrical resistance

171
Q

superposition

A

effect of two waves adding together when they meet

172
Q

temperature

A

degree of hotness of an object defined in terms of fixed points e.g. the triple point of water

173
Q

terminal speed

A

maximum speed reached by an object when the drag force on it is equal and opposite to the force causing the motion of the object

174
Q

thermal energy

A

internal energy of an object due to temperature

175
Q

thermal equilibrium

A

when no overall heat transfer occurs between two objects at the same temperature

176
Q

thermal nuclear reactor

A

nuclear reactor which has a moderator in the core

177
Q

thermistor

A

resistor which is designed to have a resistance that changes with temperature

178
Q

thinking distance

A

distance travelled by a vehicle in the time it takes the driver to react

179
Q

threshold frequency

A

minimum frequency of light that can cause the photoelectric emission for a given metal

180
Q

linear

A

two quantities are said to have a linear relationship if the change of one quantity is proportional to the change of the other

181
Q

line of force or a field line

A

indicates the direction of the force

182
Q

load

A

the force to be overcome by a machine when it shifts or raises an object

183
Q

logarithmic scale

A

a scale such that equal intervals correspond to a change by a constant factor

184
Q

longitudinal waves

A

waves with a direction of vibration parallel to the direction of propagation of the waves

185
Q

magnetic flux

A

= BA for a uniform magnetic field of flux density B that is perpendicular to an area A. Its unit is the weber (Wb)

186
Q

magnetic flux density

A

the magnetic force per unit length per unit current on a current carrying conductor at right angles to the field lines. Its unit is the Tesla (T)

187
Q

magnetic flux linkage

A

= NBA where N is the number of turns in the coil and BA is the magnetic flux. Its unit is the Weber (Wb)

188
Q

magnetic force

A 
F = BILsin(angle) F = BIL if perpendicular to field
F = BQvsin(angle) F = BQv if perpendicular to field
189
Q

mass

A

measure of the inertia or resistance to a change of motion of an object

190
Q

mass defect

A

(of a nucleus) the difference between the mass of the separated nucleons and the nucleus

191
Q

mass number

A

the number of protons and neutrons in a nucleus

192
Q

matter waves

A

the wave-like behaviour of particles of matter

193
Q

mean kinetic energy

A

for a molecule in a gas at absolute temperature T, its mean KE is 3kT/2, where k is the Boltzmann constant

194
Q

melting point

A

the temperature at which a pure substance melts

195
Q

meson

A

a hadron consisting of a quark and an antiquark

196
Q

metastable state

A

an excited state of the nuclei of an isotope that lasts long enough after alpha or beta emission for the isotope to be separated from the parent isotope

197
Q

modal dispersion

A

the lengthening of a light pulse as it travels along an optical fibre, due to rays that undergo less total internal reflection

198
Q

moderator

A

substance in a thermal nuclear reactor that slows the fission neutrons down so they can go on to produce further nuclear fission

199
Q

mole

A

one mole of a substance consisting of identical particles is the quantity of substance that contains 6.02x10^23 particles of the substance

200
Q

molar gas constant

A

R, where pV=nRT

201
Q

molarity

A

the number of moles in a certain quantity of a substance

202
Q

molar mass

A

the mass of one mole of a substance

203
Q

moment of a force about a point

A

force x perpendicular distance from the line of action of the force to the point (pivot)

204
Q

momentum

A

mass x velocity, its unit is kgm/s

205
Q

motive force

A

the force that drives a vehicle

206
Q

Beta minus radiation. (B-)

A

Electrons Electrons emitted by and stable neutron rich nuclei i.e. nuclei with a neutron/proton ratio greater than for stable nuclei.Beta minus radiation is stopped by about 5 mm of aluminium, has a range in airOf up to a metre and is less ionising than alpha radiation and more ionising than gamma radiation

207
Q

Beta plus radiation (B+)

A

Positrons omitted by unstable proton rich nuclei are you nuclei with a neutron/proton ratio smaller than the stable nuclei. Positrons omitted in solids or liquids travel no father and about 2 mm before they are eliminated.

208
Q

Binding energy of a nucleus

A

The work that must be done to separate the nucleus into its constituent neutrons and protons. Binding energy = mass defect x c^2. Binding energy in MeV = Mass defect in u x 931.3

209
Q

Binding energy per nucleon

A

The average work done per nucleon to separate a nucleus into its constituent parts. Defining energy per nucleon per the nucleus = the binding energy of the nucleus/mass number A. The binding energy per nucleon is greatest for iron nuclei of mass Number about 56. The binding energy curve is a graph of binding energy per nucleon against mass number A.

210
Q

Boiling point

A

The temperature at which a pure liquid at atmospheric pressure boils.

211
Q

Boyles Law.

A

For a fixed mass of gas at constant temperature, it’s pressure X its volume is constant. The gas that obeys Boyles Law is said to be an “ideal gas “.

212
Q

Boltzmann constant

A

The molar gas constant divided by the Avogadro number.

213
Q

Braking distance

A

The distance travelled by a vehicle in the time taken to stop it.

214
Q

Breaking stress

A

See ultimate tensile stress

215
Q

Brittle

A

Snaps without stretching or bending when subject to stress.

216
Q

Brownian motion

A

The random and unpredictable motion of a particle such as a smoke particle caused by money choose of the surrounding substance colliding at random with the particle. It’s discovery provided evidence for the existence of atoms.

217
Q

Capacitance

A

The charge stored per unit pd of a capacitor. The unit of capacitance is the farad (F), Equal to 1 coulomb per volt. For a capacitor of capacitance C at pd V, the charge stored, Q = CV

218
Q

Capacitor energy

A

Energy stored by the capacitor. See equations in book. Doesn’t let me write in Brainscape.

219
Q

Capacitor discharge

A

See book

220
Q

Celsius scale

A

Temperature in degrees Celsius or °C is defined as absolute temperature in Kelvins -273.15. This definition means that the temperature of pure melting ice is 0°C.And the temperature of steam at standard atmospheric pressure is 100°C

221
Q

Centre of mass

A

The centre of mass of the body is the point through which a single force on the body has no turning affect.

222
Q

Centripetal acceleration

A

See book

223
Q

Chain reaction

A

A series of reactions in which each reaction causes a further reaction. The nuclear reactor each fission event is due to a neutron colliding with a uranium 235 nucleus Which splits and releases two or three further neutrons that can go on to produce further fission. A steady chain reaction occurs when one fission neutron on average from each fission event produces a further fission event.

224
Q

Charge carriers

A

Charged particles that smooth a substance When a pd is applied across it

225
Q

Charles’s law

A

For a fixed mass of an ideal gas at constant temperature, its volume is directly proportional to its absolute temperature. Kelvin.

226
Q

Circuit rule for current (Kirchhoffs 1st Law)

A
  1. For two or more components in series, the total PD across all the components is equal to the sum of the PDs Across each component.
  2. The son of the EMFs round a complete loop in a circuit = the song of the PDs round the loop.
227
Q

Circuit rules for PD (Kirchhoffs 2nd law)

A
  1. For two or more components in series, the total PD across all the components is equal to the sum of the PDs across each component.
  2. The sum of the emf’s round a complete loop in a circuit = The sum of the PD’s round the loop.
228
Q

Coherent

A

Two sources of waves are coherent if they omit waves with the constant face difference.

229
Q

Conservation of momentum

A

For a system of interacting objects is the total momentum of the objects Remains constant provided no external resultant force acts on the system.

230
Q

Conservation rules

A

Conservation of energy, charge, baryon number, and lepton numbers applies to all particle interactions. Conservation of strangeness applies to strong interactions only.

13B (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions