AS Physics Vocabulary Flashcards

Comprehensive vocabulary flashcards generated from AS Physics terms and definitions notes covering Mechanics, Waves, Electricity, Nuclear Physics, and Properties of Matter.

Acceleration

The rate of change of velocity with respect to time.

Accuracy

The closeness of a reading on an instrument to the true value of the quantity being measured.

Apparent weight

The weight of an object when it is weighted in a fluid.

Centre of gravity

The point at which the whole weight of the body may act through.

Collision

An interaction between two or more objects in which linear momentum is transferred from one object to another.

Conservation of energy

Energy cannot be created or destroyed, but can be converted (or transferred) from one form to another.

Conservation of linear Momentum

The total linear momentum of an isolated system in any given direction is constant.

Couple

Two forces of equal magnitude but acting in opposite directions whose lines of action are parallel but separate.

Displacement

The distance of an object from a point, in a specified direction, from some reference point.

Efficiency

The ratio of work got out of a machine to the work put in.

Elastic collision

A collision between two or more objects in which kinetic energy is conserved.

Energy

The stored ability to do work.

Force

A vector quantity that may change the shape of an object, or if the body is free to move cause it to accelerate.

Impulse

The product of a force, $F$, acting on an object and the time $\tan(\theta)$ or $\tan(t)$ for which it acts ($\text{Impulse} = F \times \tan(t)$ , denoted as $F \times \tan(\theta)$ or time interval $\tan(t)$).

Inelastic collision

A collision in which kinetic energy is not conserved.

Kinetic energy

The energy of a mass due to its motion.

Mass

A base quantity in the SI system. A scalar quantity that is a measure of the body's resistance to changing its velocity.

Moment

The turning effect of a force.

Momentum

The product of the mass of an object and its velocity ($\text{Momentum} = \text{mass} \times \text{velocity}$).

Newton's 1st law of motion

A body stays at rest or continues with constant velocity unless a resultant force acts on it.

Newton's 2nd law

The rate of change of momentum of an object is proportional to the resultant force acting on the object and takes place in the direction of the force.

Newton's 3rd law

Whenever a force acts on a body, an equal but oppositely directed force of the same kind acts on another body.

Parallax error

A random uncertainty brought about by not looking at right angles to a scale when the scale reading is being taken.

Pressure

Force per unit area, where the force is acting at right angles to the area.

Principle of moments

For a body to be in equilibrium, the sum of all the clockwise moments about any point must equal the sum of anticlockwise moments about the same point.

Projectile motion

The resultant motion of an object when it is free to move in both the horizontal and vertical directions.

Resultant

The name given to a single vector that is equivalent, in magnitude and direction, to two or more vectors.

Speed

A scalar quantity defined by the word equation $\text{speed} = \frac{\text{distance traveled}}{\text{time taken}}$.

Spring constant

The constant of proportionality between force and extension for a sample of material that has not been stretched to such an extent that it has exceeded its elastic limit.

Terminal velocity

The constant velocity achieved by an object when it is falling under gravity through a viscous fluid.

Uncertainty

The range of values on both sides of a measurement in which the actual value of the measurement is expected to lie.

Upthrust

The force acting on an object in the vertically upward direction as a result of the object being partially or wholly immersed in a fluid.

Velocity

A vector quantity defined by the word equation $\text{velocity} = \frac{\text{change of displacement}}{\text{time taken}}$.

Amplitude

The maximum displacement of an oscillating particle from its mean position.

Antinode

A point on a stationary wave where the amplitude of vibration is a maximum.

Antiphase

Two waves are in antiphase when the phase between them is $180^\text{o}$.

Destructive interference

The interference that occurs when two or more waves meet at a point such that the resultant displacement is less than the largest individual displacement.

Diffraction

The spreading of waves at an edge or a slit so that the waves do not travel in straight lines.

Diffraction grating

A small sheet of glass or transparent plastic on which have been marked many hundreds of parallel and equally spaced lines.

Frequency

In vibration, the number of oscillations made in one second. Unit Hertz, $\text{Hz}$ or $\text{s}^{-1}$.

Laser

Light amplification by the stimulated emission of radiation. A source of monochromatic radiation in the visible, infra red or ultra violet regions of the electromagnetic spectrum.

Longitudinal wave

Wave in which the displacements of the particles in the wave are along the direction of transfer of the energy of the wave.

Monochromatic light

Light of one wavelength. Eg laser light.

Node

A point on a stationary wave where the amplitude of vibration is zero or a minimum.

Period

The time taken to complete one oscillation in a vibrating system. Related to frequency by the equation $T = \frac{1}{f}$.

Principle of superposition

When two waves meet at a point, the resultant displacement is equal to the vector sum of the individual displacements.

Progressive wave

A wave in which energy is carried from one point to another by means of vibrations or oscillations within the wave.

Sound

A pressure wave that is detected by the ear, moving through a medium and caused by a vibrating source.

Stationary Waves

A wave in which vibrational energy is stored rather than transmitted as with a progressive wave.

Transverse wave

A wave in which the displacements of the particles in the wave are at right angles to the direction of transfer of energy of the wave.

Two source interference

The pattern produced when waves from two sources meet.

Electric potential difference

The electric potential difference between two points is the work done per unit charge in moving a small positive charge between the two points.

Electromotive force

The energy transferred per unit charge from some form to electrical energy when charge is moved around a circuit.

Ohm's Law

For a conductor at constant temperature the current in the conductor is proportional to the potential difference across it.

Potential difference

The energy transferred per unit charge from electrical energy to some other form when charge passes through an electrical component.

Potential Divider

Two resistors connected in series with a supply voltage, where the potential difference across each resistor is less than the emf of the supply.

Resistance

The ratio of the potential difference $V$ across a component to the current $I$ through it.

Resistivity

The relationship between the dimensions of a specimen of material and its resistance at constant temperature, given by $\rho = \frac{RA}{l}$.

Kirchhoff's 1st law

The sum of the currents entering a junction in an electric circuit is equal to the sum of the currents leaving the junction.

Kirchhoff's 2nd law

In any closed loop in an electric circuit the algebraic sum of the emfs in the loop equals the sum of the p.ds in that loop.

Alpha particle

A particle that may be emitted from a radioactive nucleus with energies up to several $\text{MeV}$ and speeds to $0.1c$.

Anti-particle

A particle with the same properties (e.g. mass) as a nuclear particle, but opposite charge.

Atomic mass unit (u)

A unit of mass equal to one twelfth the mass of a carbon-12 atom. $1\text{ u} = 1.660540 \times 10^{-27}\text{ kg}$, with energy equivalent $931.494\text{ MeV}$.

Baryon

A particle composed of triplets of quarks, including protons and neutrons.

Lepton

A group of fundamental particles including the electron.

Beta Particle

A particle emitted from a radioactive nucleus with speeds up to $0.99c$, formed when a neutron decays to a proton and an electron.

Nuclear binding energy

The work that would have to be done to separate the nucleus into its constituent particles, or the energy released when formed.

Count rate

The rate at which emissions from a radioactive source are detected ($\text{s}^{-1}$).

Daughter nucleus

A product nucleus of a nuclear reaction.

Decay Constant

The probability of decay per unit time.

Electronvolt, eV

A non-SI unit of energy equal to the energy gained by one electron accelerated over a pd of 1 volt ($1\text{ eV} = 1.6 \times 10^{-19}\text{ J}$).

Elementary charge

The smallest quantity of charge that can exist separately.

Exponential decay

A change such that the rate of decay of a quantity is proportional to the amount of quantity at that time.

Gamma decay

The spontaneous decay of a nucleus with the emission of gamma radiation.

Hadron

A particle composed of either 2 or 3 quarks.

Isotopes

Two or more forms of the same element, having the same number of protons but different numbers of neutrons in their nuclei.

Neutron

An uncharged particle found in the nucleus with mass $m_N = 1.67 \times 10^{-27}\text{ kg}$.

Nuclear fission

The splitting of a nucleus of high nucleon number into two smaller nuclei of approximately equal mass with the release of energy.

Nuclear fusion

The building up of larger nuclei from two nuclei of smaller nucleon number, with the release of energy.

Nuclide

A particular species or type of nucleus that is specified by its proton number and neutron number.

Parent nucleus

A nucleus that is transformed into another nucleus (daughter nucleus) with the emission of particles and/or energy.

Quark

A fundamental particle that exists in pairs or triplets, such as up-quarks ($+\frac{2}{3}$ charge) and down-quarks ($-\frac{1}{3}$ charge).

Radioactive decay

The spontaneous decay of a nucleus with the emission of an alpha particle or a beta particle, usually accompanied by gamma radiation.

Randomness

The nature of radioactivity where it is impossible to predict when a specific nucleus will decay.

Archimedes principle

When an object is partially or wholly immersed in a fluid, it experiences an upthrust equal to the weight of fluid displaced.

Bar

Non-SI unit for pressure ($1\text{ Bar} = 0.1\text{ MPa}$).

Breaking Stress

The tensile stress at which a material breaks.

Brittle material

A material that shows no elasticity when subjected to a deforming stress.

Centre of Mass

The point through which a single force must act for the object to accelerate linearly without rotation.

Compression

A region in a medium where the pressure is above average.

Compressive forces

Two forces acting on an object along a line in opposite directions so as to tend to reduce its length.

Density

The mass per unit volume of a substance defined by $\text{density} = \frac{\text{mass}}{\text{volume}}$ (unit: $\text{kg}\text{ m}^{-3}$).

Drag force or Viscous force

The frictional forces experienced either by an object moving through a fluid or by a fluid passing over a solid.

Ductile material

A material that is capable of having its shape changed permanently without breaking.

Elastic deformation

A change in shape of a material such that, when distorting forces are removed, the sample returns to its original size and shape.

Elastic limit

The maximum stress which can be applied to an object such that, when removed, the object returns to its original shape and size.

Extension

The increase in length of an object as a result of applying tensile forces or heating.

Floatation

An object floats on a fluid when it displaces a weight of fluid equal to its own weight.

Freezing

The change of state of a substance from liquid to solid without any change in temperature.

Melting

The change in state of a substance from solid to liquid without change in temperature.