physics

extremely useful

transfer electrical energy into whatever form of energy we need 

like:

lamps (produce light)

electirc mixers (produce kinetic energy)

speakers (sounds energy)

television (light and sound energy)

many transfer by heating

energy is often wasted s(should be designed to waste as little as possible) 

unit for power is watt (w)

often too small to be usefull so power may be given in kilowatts (kW)

1kw = 1000watts

p=power in watts

e=energy in joules

t=time taken for energy to be transfered 

leena