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51 Cards in this Set
- Front
- Back
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Laser |
Device that produces a parallel coherent beam of monochromatic light |
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Lepton |
Electrons, positrons, muons and antimuons, neutrinos and their anti particles are classified as leptons because they can not interact through the strong interaction. They interact through the weak interaction and, in the case of electrons and positrons, through the electromagnetic interaction |
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Lepton number |
A lepton number is assigned to every lepton (+1) and every antilepton (-1) on the basis that the total lepton number for each branch of the lepton family is conserved |
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Light-dependent resistor |
Resistor which is designed to have a resistance that changes with light intensity |
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Limit of proportionality |
The limit beyond which, when a wire or spring is stretched, its extension is no longer proportional to the force that stretches it |
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Linear |
Two quantities are said to have a linear relationship if the change of one quantity is proportional to the change of the other |
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Load |
The force to be overcome by a machine when it shifts or raises an object |
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Longitudinal waves |
Waves with a direction of vibration parrallel to the direction of propagation of the waves |
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Mass |
Measure of the inertia or resistance to change of motion of an object |
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Matter waves |
The wave-like behaviour of particles of matter |
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Meson |
A hadron consisting of a quark and antiquark |
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Modal dispersion |
The lengthening of a light pulse as it travels along an optical fibre, due to rays that repeatedly undergo total internal reflection having to travel a longer distance than rays that undergo fewer internal reflections |
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Moment of a force about a point |
Force x perpendicular distance from the line of action of the force to the point |
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Momentum |
Mass x velocity |
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Motive force |
The force that drives a vehicle |
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Muon |
A lepton that is negatively charged and has a greater rest mass than the electron |
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Negative temperature coefficient |
The resistance of a semiconductor decreases when its temperature is increased |
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Neutrino |
Uncharged lepton with a very low rest mass compared with the electron |
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Neutrino types (or "branches") |
There are three types of neutrinos. The electron neutrino, the muon neutrino, and the tau neutrino. (Don't need to know tau) |
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Newton's first law of motion |
An object remains at rest or in uniform motion unless acted on by a resultant force |
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Newton's second law of motion |
The rate of change of momentum of an object is proportional to the resultant force on it. F=(^mv) / ^t [^ is a delta for this card] At constant mass, this becomes F=ma and acceleration A=(^v/^t) |
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Node |
Fixed point in a stationary wave pattern where the amplitude is zero |
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Nucleon |
A neutron or proton in the nucleus |
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Nucleon number A |
The number of neutrons and protons in a nucleus, (AKA mass number) |
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Nuclide |
A type of nucleus* with a particular number of protons and neutrons |
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Ohm's law |
The pd across a metallic conductor is proportional to the current, provided the physical conditions do not change |
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Optical fibre |
A thin flexible transparent fibre used to carry light pulses from one end to the other |
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Pair production |
When a gamma photon changes into a particle and antiparticle |
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Pascal |
Unit of pressure or stress equal to 1Nm^-2 |
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Path difference |
The difference in distances from two coherent sources to an interference fringe |
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Period |
Time for one complete cycle of a wave to pass a point |
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Phase difference |
The fraction of a cycle between the vibrations of two vibrating particles measured either in radians or degrees |
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Photoelectric effect |
Emission of electrons from a metal surface when the surface is illuminated by light of frequency greater than a minimum value known as the threshold frequency |
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Photon |
Packet or "quantum" of electromagnetic waves |
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Pion or (Pi meson) |
A Meson that consists of an up or down quarks and an up or down antiquark |
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Plane-polarised waves |
Transverse waves that vibrate in one plane only |
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Plastic deformation |
Deformation of a solid beyond its elastic limit |
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Positive temperature coefficient |
The resistance of a metal increases when its temperature is increased |
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Positron |
Antiparticle of the electron |
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Potential difference |
Work done or energy transfer per unit charge between two points when charge moves from one point to the other |
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Potential divider |
Two or more resistors in series connected to a source of pd |
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Potential energy |
The energy of an object due to its position |
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Power |
Rate of transfer of energy |
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Precision of a measurement |
Precise measurements are ones in which there is very little spread about the mean value. Precision depends only on the extent of random error and it gives no indication of how close the results are to the true value |
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Precision of an instrument |
The smallest non-zero reading that can be measured, (AKA sensitivity or resultion ) |
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Pressure |
Force per unit area acting on a surface perpendicular to the surface |
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Principle of conservation of energy |
Energy cannot be created or destroyed |
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Principle of moments |
For an object in equilibrium, the sum of the clockwise moments about any point = the sum of the anticlockwise moments about that point |
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Probable error |
Estimate of the uncertainty of a measurement |
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Progressive waves |
Waves which travel through a substance or through space if electromagnetic |
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Projectile |
A projected object in motion acted on only by the force of gravity |
