Which one of the following statements best describes the operation of a heat en…

Heat Engines

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Which one of the following statements best describes the operation of a heat engine?

 A. A heat engine transfers heat from a higher temperature reservoir to a lower temperature reservoir through work performed on the system. 

 B. A heat engine transfers heat from a lower temperature reservoir to a higher temperature reservoir through work performed on the system. 

 C. A heat engine performs work and generates an equal amount of heat in a cyclic process. 

 D. A heat engine decreases the entropy of the universe by generating an equal amount of heat and work. 

 E. A heat engine uses input heat to perform work and rejects excess heat to a lower temperature reservoir. 

I don't know

Entropy: Heat Engines

A cylinder contains Nitrogen gas (𝐶v = 20.8Jmol.K\frac{J}{mol.K}mol.KJ​  , 𝛾 = 1.4) at a pressure of 3 atm and a temperature of 250K. Its initial volume is 2.0 liters. The Nitrogen gas is next carried through the following processes:
a. It is heated in an isochoric process to a temperature of 375K
b. It is expanded at a constant temperature to a volume of 3.0 liters

Heat Engines: Otto Cycle

Otto Cycle is made of two isochoric processes at 𝑉0 and 𝑟𝑉0 for 𝑟 > 1 and two adiabatic processes which compress and extend the gas between these two volumes.
Plot PV curve of this cycle and find its efficiency in terms of only compression ratio, 𝑟 and 𝛾.

In a Stirling heat engine, a monatomic ideal gas at initial volume V1 and temperature T1, takes in heat at a constant volume until its temperature is T2, and then expands isothermally until its volume is V2. It gives out heat at a constant volume until its temperature is again T1 and then returns to its initial state by isothermal contraction. Calculate the efficiency and compare with a Carnot engine operating between the same two temperatures.

Thermodynamics: Heat Engines

A diatomic gas undergoes some thermodynamical processes according to the following plot. Imagine the process from a to b could be changed in order to get different efficiency for the following cycle under the condition that the temperature of the gas cannot exceed the temperature at point a during the entire cycle. What is the work done by the gas from a to b in a process which makes the efficiency of the heat engine equal to the half of the efficiency of a Carnot engine which works in the same range of temperatures? (Assume we have 2 moles of the gas)

PV Curve: Heat Engines

In a Diesel cycle Vo volume of gas is expanded in an isobaric process to
𝛼𝑉o and then is expanded more to 𝑟𝑉o in an adiabatic process. The gas in then cooled down via an isochoric process and then is compressed back to its initial volume. Draw PV curve of this cycle and find the efficiency of this cycle only in terms of 𝛼, 𝑟 ,and 𝛾.

Entropy: Heat Engines

A cylinder contains a diatomic gas at a pressure of 3 atm and a temperature of 250K. Its initial volume is 4.0 liters. The gas is next carried through the following processes:
a. It is expanded isobarically to a temperature of 375K.
b. It is cooled down to 250K in an isochoric process.

For heat engine cycle is clockwise
 while for heat pump cycle is counterclockwise

An engine is found to have an efficiency of 0.40. If it does 200 J of work per cycle, what are the corresponding quantities of heat absorbed and rejected? 

Which one of the following statements best describes the operation of a heat en…

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