electricity in the home- CH5

direct current

flows in one direction

alternating current

repeatedly reverses direction of flow

uk mains frequency

50hz

step-up transformers

increase voltage, decrease current

step-down transformers

increase current, decrease voltage

large pd, low current

less power lost due to resistance- more efficient

live wire

brown, carries the alternating current

neutral wire

blue, brings current back to source

earth wire

yellow and green striped, carries no current and is connected to the ground

brass

material of the pins because it conducts but doesn’t rust

short circuit

if live wire touches the neutral wire it makes a huge current, if you touch it you will get an electric shock

power supplied=

current x voltage / current^2 x resistance

charge=

current x time

resistors get hot

when a charge flows through them and energy is transferred to the resistor

useful energy=

efficiency x energy supplied