Electric Current Flashcards
electric current
Net flow of charged particles
two ways an electric current can exist
in a metal due to the movement of electrons
in an electrolyte due to the movement of ions
convectional current
the movement of current from the positive terminal of a cell to the negative (opposite to the electron flow)
electron flow
the movement of electrons from the negative to positive part of a cell
coulomb
one amp second
Kirchhoffs first law
the current entering a junction is equal to the current leaving a junction
mean drift velocity
the mean displacement of an electron along a wire per second
Potential difference
the energy transferred per unit charge from electrical energy to other forms of energy
volt
joule per coulomb
electromotive force
the energy transferred from other forms of energy to electrical energy
resistance
potential difference divided by current
ohm
one volt per amp
ohms law
potential difference is proportional to current given physical factors such as temperature remain constant
benefits of using LED’s
- More robust
- Last longer
- More efficient
- More durable
resistivity
resistance x cross sectional area/ length
why is resistivity better then resistance
resistance is affected to length and temperature
power
rate of work done
how do fuses work
a thin ceramic coated wire which is designed to carry a limited electrical current and when the current is too high it melts.
kilo-watt hour
energy equal to 3.6MJ is transferred for one hour
Kirchhoffs second law
the sum of the pd’s is equal to the sum of emf’s in a closed loop circuit due to conservation of energy
terminal potential difference
V= emf-Ir
