what are the units of frequency, amplitude and wavelength?

the wave equation?

electromagnetic waves?

effiiciency question?
a hairdryer takes in 800 j of electrical energy it gives out 100j of kinetic energy, 300j of heat energy and 400j of sound what's its efficiency?

types of energy

specific heat capacity formula and question?
the specific heat capacity of water is 4200J/KgoC. how much heat energy does it take to heat up 5kg of water by 40 degrees.

digital communications?

what are optical fibres?

heating and insulating buildings

the national grid

conduction

convection

radiation

cost of electricity formula and question?
use a 2kW oven is used for 3 hours 1.how many kilowatt hours of electricity does it use?
2. 1 kWh cost 12p, how much does it cost to use a oven for this time.