Energy and efficiency Flashcards
1
Q
The law of conservation of energy states that…
A
…energy can neither be created nor destroyed, it can only be transferred.
2
Q
True or false, 100% of energy is transferred into useful energy during an energy transfer.
A
False. Only part of the energy is usefully transferred, the rest is “wasted”.
3
Q
Wasted energy does what?
A
It is transferred to the surroundings, which become warmer. The wasted energy becomes increasingly spread out and less useful.
4
Q
Calculating the efficiency of a device. Formula:
A
Efficiency = Useful energy out/Total energy in
Or
Efficiency = Useful power out/Total power in
