Thermodynamics Concepts and Applications

What does the first law of thermodynamics state about the change in internal energy of a system?

• It is equal to the net heat transfer into the system plus the net work done on the system.

• It is equal to the net heat transfer into the system minus the net work done on the system.

• It is equal to the net heat transfer out of the system plus the net work done on the system.

• It is equal to the net work done on the system minus the net heat transfer into the system.

In the example calculation, what is the net heat transfer into the system?

• 10 Joules

• 40 Joules

• 25 Joules

• 15 Joules

What is the net work done on the system in the example calculation?

• 9 Joules

• 10 Joules

• 6 Joules

• 4 Joules

What is a heat engine?

• A device that stores heat energy.

• A device that uses mechanical energy to produce heat.

• A device that uses heat energy to do work.

• A device that converts thermal energy into electrical energy.

In a PV diagram, what does a horizontal path represent?

• Constant volume

• Constant pressure

• Changing volume

• Changing pressure

What is the work done along a vertical path in a PV diagram?

• Equal to the change in volume multiplied by the change in pressure

• Zero

• Equal to the change in pressure multiplied by the volume

• Equal to the pressure multiplied by the change in volume

What is a reversible process?

• A process where the system and environment can return to their original states by following the reverse path.

• A process where the system can only move in one direction.

• A process that is 100% efficient.

• A process that involves no heat transfer.

According to the second law of thermodynamics, what is required to transfer heat from a cool object to a hot one?

• It requires a temperature gradient.

• It happens spontaneously.

• Work must be done.

• No work is required.

What is the efficiency of a system if Qc is zero?

• 0%

• 50%

• 75%

• 100%

In the coal power plant example, what is the efficiency of the plant?

• 50.8%

• 30.8%

• 40.8%

• 60.8%