Definitions Flashcards
Define Absolute Error?
Absolute Error is the difference between a measured value and the true value.
Define Percentage Error?
(Absolute Error / True value) x 100
Define Random Error?
Random Error is error that does not follow any consistant pattern.
Define Systematic Error?
Systematic Error is error that has a consistant pattern.
Define Absolute Uncertainty?
Absolute Uncertainty is the interval in which the true value is expected to lie.
Define Percentage Uncertainty?
(Absolute Uncertainty / True value) x 100
Define Parralax Error?
Parralax Error is a form of systematic error, which is caused by the angle of the observer.
Define Anomalous Results?
Anomalous Results are results which don’t fit the pattern of the rest of the data.
Define Newton’s First Law of Motion?
An object will remain at rest or continue to move in a straight line at a constant speed unless acted upon by a resultant external force.
Define Newton’s Second law of Motion?
Force is the product of mass and acceleration.
Define Newton’s Third Law of Motion?
Every action has an equal and opposite reaction acting upon a different object.
Define Power?
The rate of work done (or the rate of energy transfer)
Define Efficiency?
Efficiency is the ratio of useful output power to total input power.
Define Moment of a Force?
Moment of a Force is the product of Force and the perpendicular distance between the force and the pivot.
Define the Principle of Moments?
The total clockwise moment is equal to the total anticlockwise moment about any point.
Define a Couple?
A Couple is a pair of equal and opposite forces that act on different points on the same object.
Define Torque?
Torque is the total moment of a couple, about any point
Define Current?
Current is the Rate of Change of Charge.
or the amount of charge flowing in one second
Define Potential Difference?
The work done per coulomb of positve charge.
Define Ohmic Conductor?
Ohmic conductors are those electrical conductors that follow Ohms law. In other words there is a linear relationship between voltage and current for all values.
Define Superconductor?
A material which below its critical temperature has ZERO resistance.
Define Semiconductor?
A material whose resistance decreases as temperature increases
Define Resistivity
Resistivity is a property that describes the extent to which a material opposes the flow of electric current through it
Define EMF?
Electromotive force
The potential difference of a supply when no current is being drawn.
Define Internal Resistance?
The electrical resisctance of a power supply.
Define Kirchoff’s First Law?
The algerbraic sum of the currents at at pount is equal to Zero.
(Or the total current flowing into a point is equal to the current flowing out of the point).
Define Kirchoff’s Second Law?
The algerbraic sum of the EMF is equal to teh sum of the potentail difference around aclosed loop.
(or total emf must be equal to pd across the components of a closed loop).
Define Period of a Wave?
The time taken for one complete oscillation.
Define Frequency of a Wave?
The number of oscillations in one second.
Define Path Difference?
The difference in distance travelled by two waves from their respective sources to a given point.
Define Phase Difference?
Phase Difference is used to describe the difference in degrees or radians when two or more alternating quantities reach their maximum or zero values.
Define Polarisation?
The action of restricting the vibrations of a transverse wave, especially light, wholly or partially to one direction.
Define Coherent Sources?
At leat on source of waves which have the same, frequencey and wave speed. And have a constant phase difference.
Define Stationary Waves?
Waves which are traveling at the same speed, in opposite directions and have the same frequency.
Define Antinode?
A point of constructive interference.
Define Node?
A point of destructive interference?
Define Work Function?
The minimum amount of energy a conduction electron must gain to leave the surface of the material.
Define Threshold Frequency?
The minimum frequency required to transfer enough energy to a conduction electron, for it to leave the surface of the material.
Define Stopping Potential?
Stopping potential is the minimum negative voltage applied to the anode to stop the photocurrent.
Define Isotopes?
Atoms which have the same number of protons by=ut z different number of neutrons.
Define Specific Charge?
The ratio of charge to mass of a ion or sub atomic particle.`
Define Antiparticle?
Particles with the same rest mass as their corresponding particle, but all other properties are opposite.
Define Elastic Deformation?
The ability for a material to return to its original size (natural length) when force is removed.
Define Plastic Deformation?
The ability for a material to NOT return to its original size (natural length) when force is removed.
Define Limit of Proportionality?
The point beyond which a material won’t return to its natural length.
Define Tensile Stress?
Force exerted per unit cross sectional area.
Define Tensile Stress?
Extension per unit length.
Define Stiff?
It requires a lot of force to stretch it.
Defene Strong?
It requires a lot of force to break it.
Define Brittle?
It breaks without much plastic deformation.
Define Ductile?
It can be pulled into thein wires (a type of platic deformation)
Define Malleable?
It can be beaten into shape (a type of plastic deformation)
define Hard?
The surface cannot be easily scratched.
Define Tough?
It will absorb a lot of energy before breaking.
Define Heat?
The transfer of thermal energy.
Define Temperature?
A measure of the mean kinetic energy of particles in an object
Define Specific Heat Capacity?
The amount of energy required to change 1 kg of material by 1 kelvin.
Define Specific Latent Heat?
The amount of energy required to change the state of 1 kg of material, without a change in temperature.
Define Pressure?
Force per unit area
Define Angular Velocity?
The rate of rotation?
Define Free Oscillator?
A system with no damping.
Define Light Damping?
A system which oscillates about the equilibrium position with (exponentialy) decreasing amplitude.
Define Heavy Damping?
A system which takes a long time to reach the equilibrium position.
Define Critical Damping?
A system reaches equilibrium and comes to rest in the shortest possible time (T/2)
Define Natural Frequency?
The frequency at which a system oscillates when not subjected to a continuous or repeated external force.
Define Newton’s Universal Law of Gravitaion?
The force of attraction between two point masses is proportional to the product of their masses. And inversly propotional to the square of their distance apart.
Define Gravitaional Field Strength?
The force acting on a unit Mass
Or the force experienced by 1 kg
Define Gravitaional Potential Energy?
The work done in moving a mass from infinitely far to a distance (r) with in a gravitaional field.
Define Escape Velocity?
The minimum velocity required to have a body leave and travel infinitely far away.
Define Gravitational Potential?
Th ework done in moving a unit mass from infinity to a distance (r) with in the gravitational field.
Define Schwartzchild Radius?
The distance from the centre of a blck hole at which the escape velocity is the speed of light.
Define Coulomb’s Law?
The force between two positive charges is proportional to the product of their charge, and inversely proportional to the square of their distance apart
Define Electric Field?
The force acting on a unit positive charge.
Define Electric Potential Energy?
The work done in moving a charge from infinity to a distance (r) within the electric field.
Define Electric Potential?
The work done in moving a unit positve charge from infinity to a distance (r) within a field.
Define Capacitance?
The amount of charge that can be stored per unit potential difference across it.
Define Relative Permittivity?
AKA Dielectric Constant.
The ratio of a materials pervittivity to that of free space.
Define Permittivity?
The measure of how easy it is to create an electric field through a medium.
Define Permittivity of Free Space?
How easy it is to create an electric field acrros a vacuum
Define Time Constant?
The time taken for a capacitor to discharge to 1/e (69%) of its initial charge
Define Relative Permeability
The ratio of a materials permeability to that of free space.
Define Permeability?
The measure of how easy it is to create a magnetic field through a medium.
Define Permeability of Free Space?
How easy it is to create a magnetic field acrros a vacuum
Define Faraday’s Law?
The Magnitude of the induced emf is equal to the rate of change of flux linkage.
Define Lenz’s Law?
The induced currentis such as to oppose the change which caused the current
Define Corrected Count Rate?
It is the cout rate of a sample after the background count rate has been factored in.
Define Alpha Decay?
When an unstable nucleus ejects a helium nucleus.
Define Beta Minus Decay?
When a neutron (in an unstable nucleus) decays into a proton, ejecting an electron.
Define Beta Plus Decay?
When a proton (in an unstable nucleus) decays into a neutron, ejecting an positron.
Define Electron Capture?
When an electron in a shell in captured by a proton in the nucleus, turning it into a neutron.
Define Radioactive Decay Constant?
The probability that an unstable nuclide will decay in one second.
Define Activity?
How many decays occur in one second, from a specific source.
Define Half Life?
The time taken for the number of unstable nuclides (or activity of a source) to halve for a given isotope.
Define Atomic Mass Unit?
The mass of 1/12 the mass of a Carbon-12 nucleus.
Define Mass Defect?
The difference in mass of the nucleus and its constiuent nucleons.
Define Binding Energy?
The work done in SEPARATING a nucleus into its constituent nucleons.
Define Binding Energy per Nucleon?
The average amount of work done to pull one nucleon from its nucleus.
Define Nuclear Fission?
The splitting of a large nucleus into two smaller daugther nuclei.
Define Nuclear Fusion?
The joining of two small nuclei to produce a larger nucleus.
Define Criticlal Mass?
The minimum mass of fissile material such that it will undergo a chain reaction. Assuming the material is spherical.
(each fission event causes at least one other fission event)
