electricity Flashcards
What is defined as the energy transferred when one coulomb of charge moves between one point and another?
(eg. through a cell or across a bulb)
potential difference
what is one volt equal to?
1 joule of energy per coulomb of charge
what is defined as the rate of flow of charge?
current
what is the capacity to do work?
energy
E = W
what is power?
the rate at which energy is transferred
(or work is done)
what 4 factors affect resistivity?
temperature
length
cross-sectional area
material
what is a superconductor
zero resistance below the critical temperature
what is the equation for resistance?
that includes resistivity
R=PL/A
resistance = resistivity x length / area
what is Ohm’s law?
current is directly proportional to potential difference
what is the property of an ideal voltmeter?
infinite resistance
what is the property of an ideal ammeter?
0 reistance
what is meant by electromotive force (e.m.f) ?
the work done in moving one coulomb of charge through the supply . this is equal to the max p.d. that the cell can supply which occurs when the current drawn is zero
or energy changed to electrical energy per coulomb passing through
what does e.m.f stand for?
electromotive force
what is internal resistance?
the resistance within the supply (eg. battery) itself
what is the effect of internal resistance?
a drop in the potential difference available from the cell
