Crossword Challenge!

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Across
  1. 3. efficiency decreases due to this reaction
  2. 5. the burning of fuel is inside the engine
  3. 7. unit for heat
  4. 9. contributed to the development of heat engines
  5. 10. converts heat to mechanical energy
Down
  1. 1. is expressed in Kelvin for computing the efficiency of heat engines
  2. 2. the ratio of output work to input work
  3. 4. the result of work done
  4. 6. the burning of fuel is outside the engine
  5. 8. the cycle consisting of four steps that operates the engine