Word Definitions Flashcards
Absolute Zero
The lowest possible temperature of a system, where no heat
remains and the particles in the system have no kinetic energy.
Boltzmann Constant
: A constant relating the average kinetic energy of the
particles in a gas, to the gas’ temperature.
Boyle’s Law
The pressure of an ideal gas is inversely proportional to its volume
when held at constant temperature.
Brownian Motion
The random motion of particles.
Charles’ Law
The volume of an ideal gas is directly proportional to its absolute
temperature when held at constant pressure.
Ideal Gas
A gas that meets the ideal gas assumptions. All the gas laws are
based on ideal gases.
Internal Energy
The sum of the randomly distributed kinetic and potential
energies of the particles in a given system.
Pressure Law
The pressure of an ideal gas is directly proportional to its absolute
temperature, when the volume is fixed.
Back Emf
An emf generated by the coil in an AC generator that acts against the
potential difference that has been supplied to the motor.
Capacitance, C
Capacitance, C: The charge stored per unit pd in a capacitor.
Dielectric
Dielectric: An insulating material placed between the two plates of a capacitor in
order to increase the amount of charge it can store.
Electric Field
A region surrounding a charged object which causes a force to be
exerted on any charged object placed within the field.
Electromagnetic Induction
When an emf is induced in a wire/conducting rod
when it is moved relative to a magnetic field.
Equipotential
A surface of constant potential. No work is done by the field when an object
moves along an equipotential.
Faraday’s Law
The magnitude of the induced emf is equal to the rate of change
of flux linkage through the circuit.
Geostationary Satellite
Geostationary Satellite: A satellite that orbits above the equator with a 24 hour period, so it
will always remain above the same position on the Earth. They orbit approximately 36,000km
above the surface of the Earth
Kepler’s Third Law:
.
Kepler’s Third Law: The square of an object’s orbital period (T) is directly proportional to the
cube of its orbital radius (r) – T^2 ∝ r^3
Lenz’s Law
An induced current is always in a direction so as to oppose the
change that caused it.
Magnetic Flux, ϕ:
Magnetic Flux, ϕ: A value which describes the magnetic field or field lines passing through
an area. It is the product of magnetic flux density and the perpendicular area it passes
through.
Magnetic Flux Density, B
Magnetic Flux Density, B: The force per unit current per unit length on a current-carrying
wire placed at 90º to the field lines. Sometimes also referred to as the magnetic field
strength.
Magnetic Flux Linkage, Nϕ:
Magnetic Flux Linkage, Nϕ: The magnetic flux multiplied by the number of turns, N, of the
coil.
Motor Effect
When a current-carrying wire is placed within a magnetic field
(non-parallel to the field lines) and experiences a force perpendicular to both the
wire and the field lines.
Permittivity of free space, ε0
A measure of the ability of a vacuum to allow an electric field
to pass through it
Polarised
An atom/molecule becomes polarised when an external electric field causes the
negative electron cloud to be shifted in the opposite direction to the positive nucleus – the
charges are pulled in opposite directions. (This is what happens to the molecules of the
dielectric in a capacitor).
