efficiency of machines Flashcards
1
Q
why is the useful energy input not usually equal to the total energy output?
A
some energy is spread out as heat
2
Q
what device is usually 100% efficient?
A
electric heaters: all the electricity is converted to ‘useful’ heat
3
Q
what is most often lost or wasted as?
A
heat
4
Q
what happens to heat transferred to surroundings?
A
it starts off as concentrated energy which is transferred to cooler surroundings which become warmer, as it is transferred the energy becomes less concentrated (it dissipates)
5
Q
how do heat exchangers work?
A
- they pump a cool fluid through the escaping heat
- the temperature of the fluid rises as it gains heat energy
- the heat energy can be converted into a form of energy that’s useful again (either in the original device or for other useful functions)
