An engine works between the two temperatures 200 C and 120 C. Calculate its efficiency in percentage?
To calculate the efficiency of an engine, we can use the formula:
Efficiency = (1 - (Tc / Th)) * 100,
where Tc is the lower temperature (in Kelvin) and Th is the higher temperature (in Kelvin).
To convert 200°C and 120°C to Kelvin, we add 273 to each temperature:
Tc = 200 + 273 = 473 K
Th = 120 + 273 = 393 K
Now we can plug these values into the efficiency formula:
Efficiency = (1 - (473 / 393)) * 100
= (1 - 1.204) * 100
= (-0.204) * 100
= -20.4%
So, the efficiency of the engine in this case is -20.4%.