Electricity Flashcards
An alternating current is
One which changes direction and instantaneous value with time
The peak value is
Always bigger than the r.m.s value
What is e.m.f
The number of joules of energy given to every coulomb of charge as it passes through a power supply/battery
What is t.p.d
The voltage across the terminals of the supply this is the same voltage across the load resistor
What is the internal resistance
The inherent resistance of the supply itself
What is an ideal supply
One which has zero internal resistance
What happens when a supply is open circuit
It has an ‘infinite’ load resistance
What is the open circuit voltage equal to
The e.m.f
When a supply is short circuited it
Has a load resistance of zero
The short circuit is
The maximum current that can be drawn from the supply
Internal resistance is
The negative gradient of a t.p.d against current graph
What is capacitance
The number of coulombs of charge stores per volt
What will happen when a capacitor is fully charged
The voltage across it will be equal to the supply voltage and there will be zero bolts across the series resistor and thus zero current
What will happen when a capacitor was is fully discharged
The voltage across it will be zero and the full supply voltage will be across the series resistor this maximum current
What happens when an atom combines to form a solid
The electrons align themselves into energy bands rather than discrete energy levels
