The law of conservation of energy is a
law of science that states that energy
cannot be created or destroyed, but
only changed from one form into
another or transferred from one object
to another.
Types of Energy
Electrical
Gravitational Potential =
stored energy in raised
objects
Kinetic = The energy
in moving objects
Magnetic = Energy in
magnets and
Electromagnets
Thermal Energy
Chemical = stored
energy in fuel, foods
and batteries
Light/Radiant Energy
Sound
Elastic Potential
Energy Processes
This diagram shows the energy transfer diagram for the useful
energy transfer in an electric lamp. You can see that the electric
lamp transfers or converts electrical energy into light energy.
Efficiency
Not all energy is transformed into the intended
output like the light bulb over there. It's practically
impossible to have a 100% efficient device. But that
wasted energy has to go somewhere because
energy cannot be created or destroyed .
Sankey diagrams are a
handy way of setting out
energy usage of a device.
Here is one for the lightbulb
As you can see a lot of
energy (90%) is wasted as heat
Device efficiency
Modern lamps use LEDs for
lighting because they are a
lot more efficient that
filament lamps