electricity Flashcards
what is an ammeter
a device that measure the current in the loop of the circuit that it is connected in series with
what is an ideal ammeter modelled as?
to have zero resistance
define current
the rate of flow of a charge in a circuit
define electromotive force (EMF)
the amount of energy transferred by a source to each unit of charge that passes through it
define internal resistance
the resistance to the flow of charge within a source
what is a light dependent resistor
a light sensitive semiconductor whose resistance decreases when light intensity increases
what is an ohmic conductor
a conductor for which the current flow is directly proportional to the potential difference across it
define ohm’s law
the current and potential difference through an ohmic conductor are directly proportional, under constant physical conditions
what is the constant of proportionality in ohm’s law?
resistance
define parallel circuits
components are connected in parallel when they are connected across each other
what is a potential divider?
a method of splitting a potential difference by connecting two resistors in series - the total p.d. is split in the ratio of their resistances
define resistance
a measure of how difficult it is for current to flow through a material
define resistivity
a quantity that is proportional to an objects resistance and area, and inversely proportional to the objects length
what is the potential difference for resistors in parallel?
identical for each resistor
what is the current for resistors in parallel?
split between the resistors
