TaAP - Second Law and Heat Engines

According to the second law of thermodynamics, the entropy of a system:

• is always decreasing.

• always stays the same.

• is always zero.

• is always increasing.

Which of the following represents the second law of thermodynamics:

• At absolute zero, the entropy of a perfect crystal is considered to be zero.

• It is impossible for a device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work.

• Energy cannot be created nor destroyed.

• If two bodies are each in thermal equilibrium with some third body, they are also in equilibrium with each other.

If there are many ways to re-order the microscopic parts of the system without changing the structure, the system has:

• High entropy

• Low entropy

• No entropy

• Infinite entropy

Heat can always be converted to work directly and completely.

• True

• False

The aim of a 'power cycle' is to:

• Use work to remove heat from a space.

• Use heat to produce useful work.

• Use heat to remove heat from a space.

• Use work to add heat to a space.

A heat engine requires 650kW of heat to generate 220kW of power. What is the cycle efficiency?

• 1

• 0.662

• 2.95

• 0.338