A-LEVEL PHYSICS: 11.2.10: Heat Engines (SaveMyExams)

Question 1

goal of a heat engine:

Answer 1

to transfer thermal energy into useful mechanical work as efficiently as possible

Question 2

efficiency of a heat engine = …

Answer 2

η = useful work out / total energy in

η = W/QH = (QH-QC)/QH

Question 3

since the efficiency of a heat engine in never ___, (otherwise there would be no ___) this means that…

Answer 3

0, work
this means that no heat engine can completely convert heat into work

Question 4

as the efficiency of a thermodynamic system increases, …

Answer 4

the difference between the temperatures of the source (TH) and the sink (TC) increases

Question 5

maximum theoretical efficiency= …

Answer 5

max. theoretical η = (TH-TC) / TH

Question 6

when can the maximum theoretical efficiency equation be used?

Answer 6

if an ideal gas is used as a substance for the engine

Question 7

to make an engine as efficient as possible, …

Answer 7

source temperature TH must be as high as possible
sink temperature TC must be as low as possible