Transferring energy by electricity (Direct voltage and Alternating voltage…
Transferring energy by electricity
Power rating of domestic appliances
The power of an appliance is measured in watts (W). A
A kettle with power rating of 3kW transfers 3000 joules of energy each second
(from mains electricity to thermal energy in water)
Direct voltage and Alternating voltage
The voltage is constantly changing but the average but the average effect is the same as D.C voltage of 230V.
D.C is mains voltage
Voltage also changes, increasing to a peak voltage then decreasing to 0
Voltage then increases to a peak in the opposite direction before decreasing back to 0.
this cycle then repeated itself 50 times per second
so the frequency is 50 hertz (Hz)
Mains electricity is produced using generators that rotate, causing the direction of the current to keep changing.
This is called Alternating Current (A.C)
Cells and batteries have positive and negative terminals and the direction of the movement of charge stays the same.
This is called Direct Current (D.C)
In our homes, appliances use the energy transferred by electricity in various ways.
the motor in a washing machine transfers energy to kinetic energy in the washing machine drum.
appliances that need a large amount of power use
In a power station energy is transferred from a store of kinetic energy (
e.g. a turbine
) by electricity.
Electricity is then carried to our homes through a network of wires and cables known as the
The gloves in
contain wire that has a high resistance.
Energy in the battery is transferred by electricity to the high resistance wires.
Here it is then transferred by heating to a store of thermal energy in the wire.
The energy is then transferred by heating to the gloves and the hands of the wearer, and eventually
to the surroundings.
As I know the higher the resistance the harder it is for current to flow and therefor the hotter the wires get.
some of the energy stored in the battery is transferred by electricity to the motor, where it is transferred to a store of kinetic energy in the fan
In the end all the energy will be transferred as thermal energy into the surroundings making it a little warmer near the fan.
Some energy will be transferred by heating the wires, motor and surroundings