(Semiconductor) diode - correct answerA semiconductor device with two terminals that allows current
to pass only in one direction. Diodes work above a minimum voltage
Absorbing photons - correct answerWhen an electron absorbs a photon, if the energy is equal to the
energy difference between the energy levels, the electron is excited
Absorption - correct answerWhen energy from a signal is absorbed by the optical fibre in which it travels
Absorption spectrum - correct answerA spectrum of dark lines seen on a coloured background when a
gas absorbs photons. For example, when a light shines through a gas, photons of certain frequencies are
absorbed, exciting the gas. During de-excitation, photons are emitted in all directions, so these
frequencies on the spectrum appear much darker
Amplitude - correct answerThe maximum displacement from the undisturbed position (for a wave)
Angle of incidence - correct answerThe angle between the incident ray and the normal ray. Notated θi
Angle of refraction - correct answerthe angle between the refracted ray and the normal ray. Notated θr
Angular displacement - correct answerThe angle (in radians) through which a line rotates about a fixed
point
Angular velocity - correct answerThe rate of change of angular displacement
Annihilation - correct answerWhen a particle meets its antiparticle, their total mass is converted into
energy in the form of two gamma ray photons. Energy and momentum are conserved
Antinode - correct answerA point of maximum amplitude on a standing wave
,Antiparticles - correct answerAll particles have a corresponding antiparticle with the same mass but
opposite charge
Antiphase - correct answerParticles along a wave that are moving in opposite directions at the same
speed. Particles are separated by a whole number of wavelengths plus a half wavelength nλ +λ/2
Baryon number (B) - correct answerQuarks have a baryon number B=1/3 and antiquarks B=-1/3.
Therefore baryons have baryon number B=1 and antibaryons B=-1
Baryons - correct answerHadrons made up of three quarks or three antiquarks, for example protons
(uud) and neutrons (udd)
Brittle materials - correct answerMaterials that show little or no plastic deformation before breaking
Centre of mass - correct answerThe point in a body around which the resultant torque due to the pull of
gravity is zero
Centripetal acceleration - correct answerThe acceleration towards the centre of the circle of a particle
moving with in a circular path
Centripetal acceleration equations - correct answera = (v^2)/r = (ω^2)r
a = Centripetal acceleration (ms^-2)
Centripetal force - correct answerThe force acting towards the centre of the a circular path that provides
the centripetal acceleration
Centripetal force equations - correct answerFc = (mv^2)/r = m(ω^2)r
Fc = Centripetal force (N)
, Cloud chambers - correct answerCharged particles form clouds in air saturated with water vapour. Can
detect alpha particles (wide straight tracks) and beta particles (thin curved or straight tracks)
Coherent waves - correct answerTwo waves with a fixed phase difference and the same frequency
Compressions (waves) - correct answerRegions of high pressure produced by a longitudinal wave
Compressive forces - correct answerForces that tend to squeeze an object and reduce its size in the
direction of the force
Conservation laws - correct answerThe following are always conserved:
- Charge Q
- Momentum p
- Mass energy E=mc^2
- Lepton number L (each generation conserved separately)
- Baryon number B
- Strangeness S (not always conserved in weak interactions)
Conservation of momentum - correct answerThe total momentum of a system does not change unless
acted upon by an external force
Conservation rules for nuclear equations - correct answerNucleon number (A) and proton number (Z)
are always conserved
Constant acceleration formulae - correct answerv = u + at
s = (u+v)t/2
s = ut + 1/2 * at^2
s = vt - 1/2 *at^2
v^2 = u^2 + 2as