05. Physics Key Terms (Physics) Flashcards
1
Q
Acceleration
A
What is defined by “The rate of change of velocity or the change of velocity per second” (in metres per second per second, m/s2).
2
Q
The number of unstable atoms that decay per second in a radioactive source.
A
What is meant by the activity of a radioactive sample?
3
Q
Alpha radiation
A
The type of radiation which is composed of two protons and two neutrons, emitted by unstable nuclei?
4
Q
Alternating current
A
The type of electrical current in a circuit that repeatedly changes its direction?
5
Q
Alternator
A
Name given to a generator which produces an alternating current?
6
Q
Amplitude
A
In a transverse wave, the maximum height of a wave crest or trough from the rest position is called?
7
Q
Angle of incidence
A
Angle between the incident ray and the normal is called?
8
Q
Angle of reflection
A
Angle between the reflected ray and the normal is called?
9
Q
Atomic number
A
The number of protons (which equals the number of electrons) in an atom. It is sometimes called the proton number or it is called?
10
Q
Beta radiation
A
Name of the emitted radiation which is composed of high energy electrons created in and emitted from, unstable nuclei?
11
Q
Big Bang theory
A
The name if the theory that the universe was created in a massive explosion from a single point, and that the universe has been expanding ever since?
12
Q
Biofuel
A
Name given to any fuel taken from living or recently living materials, such as animal waste?
13
Q
Black body radiation
A
The name of the radiation emitted by a perfect black body?
14
Q
Black dwarf
A
Name of a small star that has faded out and gone cold at the end of its lifetime?
15
Q
Black hole
A
Name of an object in space that has so much mass that nothing, not even light, can escape from its gravitational field. Formed at the end of the death of a very large star?
16
Q
Boiling point
A
The temperature at which a pure substance boils or condenses?
17
Q
Boyle’s Law
A
The law which describes that, for a fixed mass of gas at constant temperature, its pressure multiplied by its volume is constant? (pV = constant)
18
Q
Braking distance
A
The distance travelled by a vehicle during the time it takes for its brakes to act?
19
Q
Carbon neutral
A
A biofuel from a living organism that takes in as much carbon dioxide from the atmosphere as is released when the fuel is burned?
20
Q
Centripetal force
A
The resultant force towards the centre of a circle acting on an object moving in a circular path?
21
Q
Chain reaction
A
Name of reactions in which one reaction causes further reactions, which in turn cause further reactions, etc.?
22
Q
Compression
A
Name given to the area which describe the particles close together while a longitudinal wave passes through it?
23
Q
Concave (diverging) lens
A
A lens that makes parallel rays diverge (spread out)?
24
Q
Energy cannot be created or destroyed.
A
Describe what is meant by the conservation of energy.
25
In a closed system, the total momentum before an event is equal to the total momentum after the event, provided no external forces act on the objects during the interaction.
Describe what is meant by the conservation of momentum.
26
Convex (converging) lens
A lens that makes light rays parallel to the principal axis converge (meet) at a point?
27
Cosmic microwave background radiation
Name of the electromagnetic radiation that was created during and provides evidence to support the Big Bang?
28
Geiger counter (geiger-muller tube)
Device which is used to measure the count rate of a sample?
29
Dark matter
Name of the matter in a galaxy that cannot be seen? Astronomers think that stars only account for small amount of the mass of the galaxies, the rest is made of this unseen mass.
30
Deceleration
Defined as the rate of change of the velocity of an object slowing down?
31
Density
What term is defined as its mass per unit volume of a substance?
32
Diffuse reflection
Name given to reflection from a rough surface (the light rays are scattered in different directions)?
33
Diode
Name of a non-ohmic conductor that only allows current to flow in one direction once a PD over 0.6V is applied? It has a much higher resistance in its reverse direction than its forward direction.
34
Direct current
Name of a supply where the electric current in a circuit is only in one direction?
35
The line of best fit is a straight diagonal line through the origin.
If two variables are directly proportional to each other, how can you tell from the graph?
36
Displacement
Vector name given to the distance travelled in a given direction?
37
Driving force or engine force
Name of the force of a vehicle that makes it move (sometimes referred to as motive force)?
38
Dynamo
Name of a generator which produces a direct current?
39
Earth wire
The wire in a mains cable used to connect the metal case of an appliance back to the socket incase of a fault?
40
Echo
Name given to the reflection of sound that can be heard?
41
Efficiency
Name given to the ratio of the useful energy transferred by a device ÷ total energy supplied to the device?
42
Elastic behaviour
Name given to the type of behaviour demonstrated by an object which is able to regain its shape after it has been squashed or stretched and the force is removed?
43
Electric field
The name of the field created around a charged object? Which causes a non-contact force on any other charged object with in the field.
44
Electromagnet
The name of the device which consists of an insulated wire wrapped round an iron bar that becomes magnetic when there is a current in the wire?
45
Electromagnetic induction
The name of the process of inducing a potential difference in a wire by moving the wire so it cuts across the lines of force of a magnetic field?
46
Electromagnetic spectrum
The continuous spectrum of waves, with similar properties but ranging wavelengths and frequencies is called?
47
Electrons
Name of the negatively charged particles that move around the nucleus of an atom?
48
Uncertainty
The name of the term beginning with "U", given to the interval within which the true value can be expected to lie with in a measurement taken, eg "the temperature is 20 °C ± 2°C"?
49
Extension
The increase in length of a spring (or a strip of material) from its original length when a force is applied is called?
50
Fleming's left hand rule
The name of a rule that gives the direction of the force on a current-carrying wire in a magnetic field according to the directions of the current and the field?
51
Focal length
The distance from the centre of a lens to the point where light rays parallel to the principal axis are focused is called?(or, in the case of a diverging lens, appear to diverge from).
52
Force
A term which is measured in Newtons?
53
Force multiplier
Name given to an example of a lever used so that a small force can be used to increase the force applied to the object (i.e. a bottle opener)?
54
Free body force diagram
Name of the diagram that shows all the forces acting on an object (without any other objects or forces shown)?
55
Freezing point
The temperature at which a pure substance turns from a liquid to a solid?
56
Frequency
The number of wave cycles passing a fixed point every second is called?
57
Hertz, Hz.
The units used to measure frequency in? and the shorthand way to write this?
58
Frequency
Name of the term which the time period of a wave can be used to calculate?
59
Friction
The name of the contact force opposing the relative motion of two objects in contact with each other?
60
Fuse
The name of the component consisting of a thin wire that melts if too much current passes through it?
61
Gamma radiation
Name of the electromagnetic radiation emitted from unstable nuclei in radioactive substances?
62
Generator effect
The name of the effect of the production of a potential difference across the ends of a wire by passing it through a magnetic field?
63
Geothermal
Name of the energy resource where the Electrical energy comes from using the energy released by radioactive substances deep within the Earth?
64
Half-life
Name given to the average time taken for the number of radioactive nuclei present in an isotope to decay to halve its previous value?
65
Hooke's law
The name of the law which states "The extension of a spring is directly proportional to the force applied, as long as its limit of proportionality is not exceeded"?
66
Induced magnetism
Name given to process where an unmagnetised magnetic material becomes magnetic itself when placed in a magnetic field?
67
Inertia
The tendency of an object to stay at rest, or to continue in uniform motion is called?
68
Infrared radiation
Name of the electromagnetic waves between visible light and microwaves in the electromagnetic spectrum? Given out by all objects which sit above absolute zero.
69
Internal energy
The name of the energy of the particles of a substance, due to their individual motion and positions
70
Looking at the data and graph, as one variable becomes "n" times bigger, the other variable becomes "n" times smaller (i.e. if one doubles, the other halves)
If two variables are inversely proportional, how can you tell from the data?
71
Ion
The name of an atom which has lost an electron to become charged?
72
Ionisation
The name given to the process where an atom loses an electron to become charged?
73
The object has been exposed to ionising radiation.
What is meant by an object has been "irradiated"?
74
Atoms with the same number of protons but different numbers of neutrons in the nucleus.
Define what is meant by the term "isotope"?
75
Latent heat
The name given to energy transferred to or from a substance when it changes its state?
76
Light-depending resistor (LDR)
Name of a resistor whose resistance depends on the intensity of the light incident on it?
77
Light-emitting diode (LED)
A device which emits light when a current flows through it in the forward direction?
78
Limit of proportionality
The name given to the point on a force-extension graph where Hooke's law no longer applies past this point, during the extension of a stretched spring?
79
Live wire
The name of the mains wire which has a voltage that alternates in size and direction (between +325 V and 325 V in Europe)?
80
Longitudinal waves
The type of waves in which the vibrations(oscillations) are parallel to the direction of energy transfer?
81
Magnetic field
The type of field found around a current-carrying wire?
82
Magnetic flux density
Name given to the term which is a measure of the strength of the magnetic field?
83
The image height ÷ the object height.
How you would calculate the magnification of a lens using the both the object and image sizes?
84
Converging lens
The type of lens used to magnify a small object (object must be placed between the lens and its focal point)?
85
Main sequence
The name given to the stable period of a star during which it radiates energy because of fusion of hydrogen nuclei in its core?
86
Mass
The name given to the quantity of matter in an object? (measured in kilograms, kg)
87
The number of protons and neutrons
The mass number of the nucleus tells us?
88
Mechanical wave
Name given to the group of waves which require a substance to be present to travel through it?
89
Melting point
The temperature at which a pure substance changes from solid to liquid during heating or solidifies during cooling?
90
Microwaves
Electromagnetic waves between infrared radiation and radio waves in the electromagnetic spectrum?
91
Moderator
Name of the substance in a nuclear reactor that slows down fission neutrons so further nuclear fission can take place?
92
Moment
The turning effect of a force defined by the equation: force (in newtons, N) × perpendicular distance from the pivot to the line of action of the force (in metres, m).
93
Momentum
The name given to the term equal to the mass × velocity of a moving object?
94
Motor effect
When a current is passed along a wire in a magnetic field the wire can experience a force. What is the name of this effect called?
95
National Grid
The name given to the network of cables and transformers used to transfer electricity from power stations to consumers (i.e., homes, shops, offices, factories, etc.)?
96
Neutral wire
The name of the wire of a mains circuit that is involved in the transfer of electrical current to and back from a device, however the pd of this wire remains close to 0V?
97
Neutron star
The name of the highly compressed core of a massive star that remains after a supernova explosion?
98
Neutrons
Uncharged particles of the same mass as protons?
99
If the resultant force on an object is zero, the object either remains at rest, or it keeps moving with a constant speed (in the same direction).
State Newton's first law of motion?
100
The acceleration of an object is proportional to the resultant force on an object. (and inversely proportional to the mass of the object.)
State Newton's second law of motion?
101
When two objects interact with each other, they exert equal and opposite forces on each other.
State Newton's third law of motion?
102
Normal
Name of the straight line perpendicular to the surface or boundary, from which angles of incidence etc are measured from?
103
Nuclear fission
The name of the process in which certain nuclei (uranium-235 and plutonium-239) split into two fragments, releasing energy and two or three neutrons as a result?
104
Nuclear fusion
The name of the process where small nuclei are forced together to fuse and form a larger nucleus?
105
Nucleus
Name of the positively charged centre of every atom?
106
The current through a resistor (at constant temperature) is directly proportional to the pd across the resistor.
State what is meant by a resistor obeying Ohm's law?
107
Opaque object
Name given to a surface/object which light cannot pass through?
108
Optical fibre
Name given to a thin glass fibre which is used to transmit light signals?
109
Oscilloscope
A device used to display the shape of an electrical wave? Useful alongside microphones to analyse sound signals etc.
110
Parallelogram of forces
Name given to a geometrical method used to find the resultant of two forces that do not act along the same line?
111
Potential difference
The name given to a measure of the energy transferred to a device by each coulomb of charge that passes through it?
112
Power
The name given to a measure of the energy transferred per second?
113
Pressure
Name of term defined as the "Force per meter squared" acting on a surface? Measured in pascal (Pa).
114
Primary wave (P-wave)
Type of seismic waves which are longitudinal waves?
115
For an object in equilibrium, the sum of all the clockwise moments about any point = the sum of all the anti-clockwise moments about that point.
State what is meant by the principle of moments?
116
Protons
Positively charged particles with an equal and opposite charge to that of an electron?
117
Protostar
The name given to a concentration of dust clouds and gas in space that forms a star?
118
Radiation dose
The name given to the amount of ionising radiation a person receives/absorbs?
119
Radio waves
Electromagnetic waves of wavelengths greater than 0.10 m?
120
(Radioactive) Contamination
The name given to the unwanted presence of materials containing radioactive atoms on other materials?
121
Rarefaction
Name given to the area in a longitudinal wave which cause the particles to be spread out?
122
Reactor core
Name of the thick steel vessel which contain fuel rods, control rods and the moderator in a nuclear fission reactor?
123
Real image
Name given to an image formed by a lens that can be projected on a screen?
124
Red giant
Name of the stage of a small star that has expanded and cooled, once the hydrogen begins to run out at the end of its stable period?
125
Red supergiant
Name of the stage of a large star that has expanded, once the hydrogen begins to run out at the end of its stable period?
126
Redshift
Name given to the increase in the wavelength of electromagnetic waves emitted by a star or galaxy due to its motion away from us?
127
Refraction
The change of direction of a light ray when it passes across a boundary between two transparent substances (including air)?
128
Renewable energy
Name of the energy source from natural sources that is always being replenished so it never runs out?
129
Resistance
Term which can be calculated from the equation - potential difference (in volts, V) ÷ current (in amperes, A)?
130
Resultant force
Name given to the single force which can be used to represent the sum of all the forces acting on an object?
131
Scalar
The general name given to a physical quantity, such as mass or energy, that has magnitude only?
132
Secondary waves (S-waves)
Type of seismic waves which are transverse waves?
133
Seismic waves
Shock waves that travel through the Earth and across its surface from the epicentre of an earthquake
134
Series
Name of a type of circuit which has its components connected in such a way that the same current passes through each of them?
135
Solenoid
The name of a long coil of wire that produces a magnetic field both inside and around the outside of a coil when there is a current in the coil?
136
Specific heat capacity
Defined as the "Energy needed to raise the temperature of 1 kg of a substance by 1 °C"?
137
Specific latent heat of fusion
Defined as the "Energy needed to melt 1 kg of a substance with no change of temperature"?
138
Specific latent heat of vaporisation
Defined as the "Energy needed to boil away 1 kg of a substance with no change of temperature"?
139
Specular reflection
S__________ reflection - the name given to reflection from a smooth surface? Each light ray is reflected in a single direction.
140
Speed
Term calculated using - distance moved by the object ÷ time taken to move the distance travelled.
141
Spring constant
Term represented by "k", which indicates the force required to extend a material per metre?
142
Step-down transformer
Electrical device that is used to decrease the size of an alternating potential difference?
143
Step-up transformer
Electrical device used to increase the size of an alternating potential difference?
144
Stopping distance
The name given to the total distance travelled by the vehicle in the time it takes for the driver to react and brake?
145
Supernova
The explosion of a massive star after fusion in its core ceases and the matter surrounding its core collapses on to the core and rebounds?
146
Tangent
Name given to a straight line drawn so it touches a point on a curve at one point (it has the same gradient as the curve at that point)?
147
Terminal velocity
The name given to the velocity reached by an object when the drag force on it is equal and opposite to the force making it move?
148
Thermal conductivity
A property of a material that determines the rate of energy transfer through it by conduction?
149
Thermistor
Name of a resistor whose resistance depends on the temperature of its surroundings?
150
Thinking distance
The name given to the distance travelled by a vehicle in the time it takes the driver to react?
151
Live, Neutral an Earth
What is the name of the three-pins present in a three-pin plug?
152
Transformer
Name of the electrical device used to change the size of an (alternating) voltage?
153
It could be absorbed, relected or transmitted.
When a beam of light is used to illuminate an object, what three possible things can happen to the beam of light on striking the surface?
154
Transparent object
Name given to an object that transmits all of the incident light that enters the object?
155
Transverse wave
The type of wave where the particle vibration is perpendicular to the direction of energy transfer?
156
Ultrasound wave
Sound wave at frequency greater than 20 000 Hz (the upper frequency limit of the human ear)?
157
Ultraviolet radiation
Electromagnetic waves found with a wavelength between visible light and X-rays in the electromagnetic spectrum?
158
Vector
The general name of a physical quantity, such as displacement or velocity, that has both a magnitude and a direction?
159
Velocity
Name of the speed of an object in a given direction?
160
Wavelength
The distance from one wave crest to the next?
161
Weight
The force exerted by an object due to gravity acting on it?
162
White dwarf
Name given to the stage of a star that has collapsed from the red giant stage to become much smaller, hotter and denser state?
163
Work done
Term calculated using the equation - force × distance moved?
164
X-rays and gamma rays
Electromagnetic waves smaller in wavelength than ultraviolet radiation?
