efficiency of machines Flashcards

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1
Q

why is the useful energy input not usually equal to the total energy output?

A

some energy is spread out as heat

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2
Q

what device is usually 100% efficient?

A

electric heaters: all the electricity is converted to ‘useful’ heat

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3
Q

what is most often lost or wasted as?

A

heat

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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)

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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)
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