Terminology Flashcards
1
Q
Accuracy
A
How close a measurement is to it’s true value, influenced by the systematic and random errors of that measurement.
2
Q
Base Units
A
The set of seven basic measures from which all other SI units can be derived
3
Q
Estimation
A
Making a reasonable approximation of a value in order to check a calculation or make a quick comparison to another value
4
Q
Precision
A
How close a set of repeated measurements are to one another but not the true value, influenced by the random errors of those measurements
5
Q
Random error
A
The unpredictable variation in a measurement. These can be reduced by taking many repeated measurements and calculating their mean
6
Q
Repeatability
A
An experiment is said to be repeatable if the same person with the same equipment obtains the same result when doing the same experiment a number of times, over a short time period
7
Q
Reproducibility
A
An experiment is said to be reproduceable if different people with different equipment, measuring the same quantity, get a similar result.
8
Q
Resolution
A
The smallest interval that a given measuring device can measure
9
Q
Systematic error
A
A consistent shift in readings causing a deviation from the true value. This shift is due to the equipment or method being used and cannot be reduced by repeated measurements
10
Q
Uncertainty
A
The range of values that could reasonably contain the true value of a measurement, based on the confidence an experimenter has about their result.
11
Q
Work done
A
A force applied over a distance. The energy transferred in that distance
12
Q
Weight
A
The force of gravity on an object, the product of the objects mass and the acceleration due to gravity
13
Q
Vector
A
A quantity with magnitude and direction
14
Q
Terminal velocity
A
The max velocity an object can achieve, point at which frictional forces and driving forces are balanced so no acceleration and resultant force=0N
15
Q
Scalar
A
A quantity with only magnitude and no direction
16
Q
Resultant force
A
The sum of all forces on an object
17
Q
Newton’s third law
A
Every action has an equal and opposite reaction. Equal in magnitude but opposite in direction
18
Q
Newton’s 2nd law
A
If an object is acted on by a resultant force it will accelerate. The acceleration is inversely proportional to the mass of the object and directly proportional to the force acting on it
19
Q
Newton’s 1st law
A
An object at a constant velocity will remain at a constant velocity unless acted on by a resultant force
20
Q
Momentum
A
The product of an object’s mass and it’s velocity
21
Q
Moment
A
The product of a force and the perpendicular distance from the line of action to the pivot about which the force is acting
22
Q
Lift
A
A force acting perpendicular to the flow of air or liquid around an object, typically upwards and against the force of gravity
23
Q
Kinetic energy
A
The energy an object has due to it’s motion.
24
Q
Inelastic collision
A
When the kinetic energy of a system before an event is not equal to the kinetic energy of a system after the event
25
Gravitational potential energy
The energy gained by an object when it is raised by a height in a gravitational field
26
Impulse
The change of momentum of an object when a force acts on it. Area under a force-time graph
27
Friction
The resistance against the motion of an object. This could be caused by the air passing over the object or by the contact of the object with the surface it is moving on
28
Force
The rate of change of momentum of an object. The product of the object's mass with it's acceleration
29
Equillibrium
An object is at equilibrium when the moments on it about a point are balanced and the resultant force is zero
30
Elastic collision
Kinetic energy of a system before an event is equal to the kinetic energy of the system after
31
Efficiency
The useful output of a system divided by the total output
32
Drag
The resistance against the motion of an object through a fluid
33
Conservation of momentum
In a closed system with no external forces, momentum of a system before an event is equal to the momentum after an event
34
Conservation of energy
In a closed system with no external forces, the energy of a system before an event is equal to the energy of the system after an event
35
Centre of mass
The point through which the total mass of the object is said to act
36
Conventional current flow
positive to negative
37
Current
The rate of flow of charge in a circuit
38
Detecting circuit
A circuit with a potential divider with one of the resistors being a semiconductor which when an external condition changes will change its resistance and change the voltage across the other resistor
39
Diode
Components that allow current through in one direction. In the correct direction, diodes have a threshold voltage after which current flows normally
40
EMF
The energy supplied by a source per unit charge passing through the source
41
Electron flow
The actual flow of electrons in a circuit, from negative to positive
42
Internal resistance
The resistance any power source will have that makes it harder for current to flow through the source, causes energy to be dissipated in the cource
43
Kirchoff's 1st law
Total current entering a junction is equal to the total current leaving it
44
Kirchoff's 2nd law
The sum of EMF in any loop of a circuit is equal to the sum of the potential differences of each component
45
Light dependent resistors
Components whose resistance decreases when light intensity increases
46
Ohmic conductor
A conductor following Ohm's law where current flowing through it is directly proportional to the potential difference between each end of the conductor. At a constant temperature
47
Ohm's law
Electric current is proportional to potential difference and inversely proportional to resistance
48
Potential difference
The difference in electrical potential between two points in a circuit and the work done required to move a charge from lower potential point to higher point.
49
Potential Divider
A combination of two or more resistors in series. Result in the potential difference of a circuit being split into a specific ratio depending on the resistance of the resistors.
50
Power
Rate of energy transfer
51
Resistance
A measure of how difficult it is for current to flow in a circuit or component
52
Resistivity
A measure of how difficult it is for charge to travel through a material, depending on the materials cross sectional area, length and resistance.
53
Semiconductors
Materials that change their resistance depending on external conditions
54
Terminal potential difference
The actual potential difference across the terminals of a power source.
55
Thermistor
A component whose resistance decreases when temperature increases
56
Variable resistors
A resistor that can have it's resistance changed.
57
Voltmeter
A device used to measure potential difference between two points on a circuit, ideally has infinite resistance
58
Topic 5
Missing
59
Angular displacement
In circular motion, the angle turned through
60
Angular velocity
Angular displacement per unit time. Defined in clockwise or anticlockwise direction
61
Centripetal acceleration
As a body follows an object it's direction constantly changes, this produces a constantly changing velocity and the acceleration is needed to cause this change in velocity
62
Centripetal force
The result forces of an object travelling in a circle directed to the centre of orbit dur to the centripetal acceleration
63
Capacitance
The ratio of the charge stored in a capacitor to the potential difference
between the two sides of the capacitor.
64
Coulombs Law
The size of the force that acts between two point charges is
proportional to the product of their charges and inversely proportional to the
square of their separation. It is attractive for opposite charges and repulsive for
like charges.
65
Dielectric
An insulating material placed between capacitor plates that prevents charge from
crossing between the plates. The dielectric becomes polarised when the capacitor is charged
and changes the capacitance of the capacitor.
66
Eddy Current
Small closed loops of current within a conductor or magnet. In a transformer
these currents act against the magnetic flux that generates a current in the secondary coil
making the transformer less efficient and heating the core.
67
Electric Field
A region of space in which charged particles experience either an attractive or
repulsive force depending on the charge of the particle and direction of the field.
68
Electric field lines
A way of representing an electric field in a diagram, they point in the
direction that a positive charge would experience a force, point positive to negative.
69
Electric field strength
The electrostatic force experienced by a unit positive charge at that point in a field
70
Electric potential
The work done moving a unit positive charge from an infinite distance away to that point
71
Electric potential difference
Work done moving a unit positive charge between two points
72
Electromagnetic induction
When a current carrying conductor moves relative to a magnetic field an EMF is induced in the conductor
73
Electrostatic force
The force generated between charged due to Coulomb's Law
74
Equipotential
Planes of points where the electric potential is the same, no work is done moving a charge along these
75
76
Faraday's law
The magnitude of the induced EMF is directly proportional to the rate of change of magnetic flux linkage
77
Fleming's Left Hand Rule
The relative direction of motion, field direction and current
direction in the motor effect can be represented by the thumb, first finger and second finger
of the left hand respectively. For the motion of a charged particle in a magnetic field, its
direction replaces the current direction.
78
Frequency
Number of complete oscillations of current or V in AC circuit per second
79
Lamination
Transformers core made up of sets of layers to prevent eddy currents
80
Lenz's law
The direction of an induced current is such that is opposes the current that created it
81
Magnetic field
A region of space in which magnetic materials and moving electric charges feel a force
82
Magnetic flux
the magnetic field passing through a given area
83
Magnetic flux density
The strength of a magnetic field
84
Magnetic flux linkage
The magnetic flux of a coil found by product of magnetic flux and turns in coil
85
Motor effect
Force felt by a current carrying wire in a magnetic field
86
Oscilloscope
Device used to monitor periodically time changing quantities such as V or I in an AC circuit
87
Peak value
Max V or I an AC circuit achieves
88
Period
Time taken for I or V in AC circuit to complete one full cycle
89
Radial field
A field with field lines originating from a point
90
RMS value
Value of V or I that would produce same power dissipation is DC circuit as AC circuit
91
Time constant
Time taken for capacitor to discharge from full to 37% of its original value
92
Uniform field
A field with parallel field lines
93
Transformer
A device used to increase or decrease the voltage with two sets of coils with
different numbers of turns wrapped around a magnetic core. The transformer is step-up if the
number of coils on the secondary coil is greater than the number on the primary coil. The
transformer is step-down if the number of coils on the secondary coil is fewer than the
number on the primary coil.
94
Antimatter
A particle with the same mass as its matter particle but with opposite charge and quantum numbers
95
Baryon
A particle consisting of three quarks.
96
Baryon number
A measure of if a particle is a baryon. +1 for a baryon, -1 for an antibaryon
97
Cyclotron
A particle accelerator that has two semicircular electrodes with a gap between.
When a charged particle is in the electrodes it is curved due to the magnetic field
perpendicular to the plane of the electrodes and when it is in the gap it accelerates in an
alternating voltage electric field resulting in a spiral path and accelerated charged particle.
98
Fundamental particles
Particles that cannot be broken down into smaller constituents
99
Gauge boson
Fundamental particles that are the carriers of the fundamental forces
100
Gluon
Gauge boson of the strong interaction
101
Hadron
Particles that undergo strong interaction, made of quarks
102
Leptons
Fundamental particles that do not interact via the strong force. They can transform
between flavours via the weak interaction and some have charge so undergo
electromagnetic interactions. They include the electron, electron neutrino, muon, muon
neutrino, tau and tau neutrino.
103
Lepton number
A measure for if a particle is a Lepton. Muons, Taons and electrons have different Lepton number versions
104
Linac
Accelerate charged particles through sets of oscillating electric fields that create large electric potentials that accelerate the particles
105
Meson
A particle consisting of one quark and one antiquark
106
Nucleon number
Number of neutrons and protons in the nucleus
107
Photon
Gauge boson of the EM force
108
Plum pudding model
A model of the atom that describes it as a ball of positive charge with
evenly distributed negative electrons throughout it.
109
Proton number
Number of protons in the nucleus (duh)
110
Quark
Fundamental particle that interacts with other quarks via the strong interaction, it will
change flavour via the weak interaction and annihilate with antiquarks to form photons via the
electromagnetic interaction. They come in 6 flavours: up, down, charm, strange, top, bottom.
111
Quark confinement
The principle that states that quarks cannot exist alone and must be
either in quark, antiquark pairs or in threes.
112
Relativistic motion
Particles that are travelling close to the speed of light, they will experience time at a slower rate than a non relativistic particle
113
Strangeness
A measure of how many strange/antistrange quarks a particle has (I think + is anti and - is regular)
114
Thermionic emission
When a metal is heated free electrons gain sufficient kinetic energy
and are released from the metal’s surface.
115
Weak interaction
The force that causes flavour change in quarks and leptons, it is
responsible for beta decay.
116
W+ W- Z0
Gauge bosons of the weak interaction
