1.1 Appliances transfer energy but they rarely transfer all of the
energy to the place we want. We need to know the efficiency of
appliances so that we can choose between them, including how
cost effective they are, and try to improve them.
1.1.1 Energy can be transferred usefully, stored, or dissipated, but
cannot be created or destroyed.
220.127.116.11 When energy is
transferred only part
of it may be usefully
transferred, the rest is
18.104.22.168.1 Wasted energy is eventually
transferred to the surroundings,
which become warmer. The wasted
energy becomes increasingly spread
out and so becomes less useful.
22.214.171.124.1.1 To calculate the efficiency of a device use the following
equations: efficiency=useful energy out/total energy in
(x100%) or efficiency=useful power out/total power in