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current which reverses its direction of
flow over time - usually viewed as a "wave" trace on an
oscilloscope |
|
the unit of electric current - when a
charge of one coulomb flows for one second |
|
A in r = R A / L |
|
The greatest stress a material can bear
is called the ______ _________ |
|
a material that will usually fracture
with very little force applied can be described as being _____ |
|
the quantity of electricity - expressed
as a positivity or a negativity - can be measured in coulombs |
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the unit of charge |
|
the rate of flow of charge |
|
mass per unit volume |
|
the force beyond which a material
should not be subjected if it is to obey Hookes Law |
|
_____ _________ ________ = area under
the Hooke's law portion of a Force / extension graph |
|
the energy provided by a power source
per unit charge - it is also the pd of the power source when no current
flows |
|
emf is related to the ______ provided
per unit charge within the power supply |
|
____ _______ in stretching a material =
1/2 force x extension |
|
I / V characteristic shows a
symmetrical curve for this non-ohmic conductor |
|
vibrations in a time interval - also it
is f in f =
1 /
T |
|
the number of vibrations per second |
|
when a forces is applied to a material
& the force is proportional to extension
- then it obeys _____ _____ |
|
the resistance inherent in any power
source in which energy is dissipated |
|
to calculate the sum of parallel
resistors we need to _____ each resistance before we add them and then
_____ the result |
|
the unit of energy |
|
the laws which describe how current and
voltage are distributed in series and parallel circuits |
|
L in r = R A / L |
|
the unit of resistance = 1 volt per
ampere |
|
the unit of resistivity |
|
a conductor that obeys ohm's law - in
which V is proportional to I at constant temperature |
|
this law applies when current is
proportional to voltage at constant temperature |
|
a device used to display a.c. waveforms
on a cathode ray tube |
|
a method of connecting components in
which each component has its own branch before and after the component -
they share the same p.d. |
|
the maximum voltage of
a.c. measured from the central position (equivalent to amplitude) |
|
a material that retains some of its
extension after the force has been removed can be described as being
________ |
|
the work done per unit charge - usually
measured across a component in a circuit |
|
a network of (usually) two resistors
connected in series that allows the voltage to be shared across each
resistance |
|
the rate of energy dissipation |
|
the ratio of potential difference to
current |
|
the resistance of a material taking
into account its length and its cross sectional area |
|
the rms value of current or voltage in
ac circuits - the value that gives the effective power output when
compared to its d.c. equivalent |
|
a conductor that conducts electricity
in one direction only |
|
a method of connecting components in
which there are no branches - all the electricity flows though each
component with the same current |
|
the shape of an a.c. wave form that
follows this pattern x = sin(x) |
|
ohm's law only applies at constant
______ |
|
______ ______ = extension / original length |
|
_____ ______ = force acting on the cross sectional area of a
material under tension |
|
a device which is designed to have a
resistance that depends upon its temperature: an inc. T leads to a dec. R |
|
the control on a CRO that allows us to
vary the time taken for the moving electron beam to move through one
horizontal division |
|
the time between subsequent peaks (or
troughs) in an a.c. wave form - also the shortest time interval between
two parts of a wave form that have the same phase difference |
|
the unit of emf and potential
difference = one joule dissipated per coulomb of charge |
|
the control on a CRO that allows us to
vary the voltage required to move the beam through on vertical division |
|
_____ ______ = force x distance moved -
it is also related to the energy dissipated in components having
resistance |
|
tensile stress / tensile strain |