Topic 2 - Energy and Power in Circuits Flashcards
what happens when there is an electric current in a resistor?
an energy transfer that heats up the resistor
why is the resistor heated up?
electrons collide with the ions in the lattice that make up the resistor. this gives the ions energy, so they vibrate and heat up
what does heating up the resistor do to the resistance?
it increases the resistance
how does the heating effect on a resistor help fuses work?
it can cause fuses to melt. this means if the current is too high the fuse will melt and the circuit will break.
what is electrical power?
the rate at which an appliance transfers energy
if an appliance has a high power rating how much energy does it transfer?
a lot of energy in a short time
where does the energy an appliance transfers come from?
the current flowing through it
does an appliance with a high power rating draw a large or small current?
a large current
what should the rating of a fuse be compared to the normal operating current?
as near as possible but just higher
what is the formula for electrical power?
electrical power = current x voltage
what does energy transferred depend on?
the power of the appliance and how long its on for
what is the formula for energy transferred?
energy transferred = current x voltage x time
