Science - Electrical Energy

neutrons

neutral particle that make up an atom

protons

positive particle that make up an atom

electrons

negative particle that make up an atom

what is electricity?

the flow of electrons through a conductor e.g a wire

what is voltage aka?

potential difference

what is voltage?

the amount of energy given for electrons to travel through a conductor

what is it measured in? what is it measured with?

volts and voltmeter

where do you connect it to on a circuit?

in parallel to what is being measured e.g light globe

what is current?

rate of flow of charge that passes through a point in the circuit

what is used to measure a current? what is it measured with?

amperes and ammeter

where do you connect it in a circuit?

in series with the circuit

what is resistance?

a measure of how much a material (normally a wire) reduces the electric current flow through it

what is resistance measured by?

Ohms

what is Ohm’s law?

V=IR, where V is voltage, I is current and R is resistance

what is a combination circuit?

a combination of both parallel and series circuits

what is direct current (DC)?

direct current is the flow of current that only occurs in one direction e.g portable electronics which require batteries

what is alternating current (AC)?

the flow of current alternates back and forth multiple times a second (50Hz for Australia) eg. large appliances that require lots of power

what are fuses?

fuses are used in circuits and are designed to burn and break the circuit once a high enough current is reached to prevent fires ( bc circuits heat up )

what are the characteristics of a fuse?

• conductive wire

• high resistance

• low melting point

what are circuit breakers?

same purpose as a fuse, but allows the circuit to be restored with a switch rather than having to replace it

how do you restore the normal function of the circuit when using circuit breakers?

a switch has to be flicked to manually restore normal function to the circuit

what are earth wires?

three prongs that have three wires connected to them

what are the three wires of earth wires?

active wire, neutral wire, earth wire

what is an active wire?

carries current to the power point

what is a neutral wire?

carries current away from the power point

what is an earth wire?

connects the power point to the earth beneath

why are earth wires good in households?

if an appliance is faulty, earth wires are introduced to carry any dangerous currents back to the power point to the ground as opposed to through you

what is the law of conservation of energy?

energy cannot be created or destroyed, it can only be transferred or transformed

what is produced from every energy interaction?

emissions

why is energy efficiency always less than 100%?

every transfer of energy has some non-useful component, hence its efficiency is always less than 100%

what is the formula for energy efficiency?

efficiency = useful output of energy / input