Energy ► Efficiency ► Ideas Map

Supplied Energy

Useful Energy

Wasted Energy

Energy ► Efficiency ► Useful and Non►Useful

• Whenever energy is transferred, only part of it is transferred to where it is wanted and in the form it is wanted (usefully transferred).

• The rest of the energy is transferred in some non-useful way and so wasted.

Movement is useful

Heating atmosphere is not useful

Energy ► Efficiency ► Types of Energy

ElectricalInput Energy

MovementUseful output Energy

Sound

heat}

Lost

Energ

y

Energy ► Efficiency ► Calculation

• The efficiency of a device can be calculated using:

100 J

Movement 30J

Heat 60J

Sound 10J

Efficiency = EOut(useful)/Ein = 30J/100J = 0.3 = 30%