P1.3.1 Energy Transfer

Question 1

Electrical energy~ whenever a current flows
Light energy~ from the sun light bulbs etc.
Sound energy~ loudspeakers or anything noisy
Kinetic or movement energy~ anything that’s moving

Answer 1

Nuclear energy~ released only from the nuclear reactions
Thermal or heat energy~ from hot objects to colder ones
Gravitational potential energy~ anything which can fall
Elastic potential energy~ stretched springs, elastic, rubber bands etc.
Chemical energy~ foods,fuels, batteries

Question 2

It is really simple to calculate efficiency

Answer 2

Efficiency = useful energy out/
Total energy in

Efficiency = useful power out/
Total power in

Question 3

Energy transformation diagrams

Answer 3

The thickness of the arrow represents the amount of energy.

Question 4

The cost of electricity

Answer 4

Kilowatt-hours (KWH) are “units” of energy

Use the energy = power X time triangle

A kilowatt- hour is the amount of electrical energy used by a 1kw appliance left on for 1 hour

The two easy formulas for calculating the cost of electricity:
Units(kWh)used = power(kW) X time (hours)
OR
Cost= units X price