Question 1

Two processes are shown on the p-V graph in Figure 12-1; one is an adiabat and the other is an isotherm. Is the process represented by the upper curve an adiabat or an isotherm?

Accepted Answer

isotherm

Question 2

Why don't we use "efficiency" for rating refrigerators, like we rate engines, instead of the Coefficient of Performance?

Accepted Answer

In both cases we desire a ratio of "what we want" divided by "what it costs"; for a refrig. this is "heat absorbed"/"work input" (COP) but for an engine this is "work out"/"heat in" (= eff).

Question 3

Is it possible for heat to travel from a cold object to a hotter object?

Accepted Answer

Yes (your refrigerator does this all the time), but only with the expenditure of work.

Question 4

We say that energy cannot be created nor destroyed, yet a heat pump usually delivers more energy (heat) into the house than it receives from the power source (electricity, gas, etc). Why is this not a violation of the law of conservation of energy?

Accepted Answer

The answer of We say that energy cannot be created...

Question 5

Both the refrigerator and the heat pump take in heat and expel it at a higher temperature. Why don't they have the same Coefficient of Performances?

Accepted Answer

The answer of Both the refrigerator and the heat pump...

Question 6

As a system loses the ability to do work, its entropy decreases.

Accepted Answer

As a system loses the ability to do work, its entropy increases, reflecting a move towards disorder and less available energy to do work.

Question 7

Entropy is a measure of order. The more order there is, the higher the system's entropy.

Accepted Answer

Entropy is a measure of disorder or randomness in a system; the more disorder there is, the higher the system's entropy.

Question 8

Entropy of the universe is increasing.

Accepted Answer

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible. Since the universe is considered an isolated system, its total entropy is always increasing.

Question 9

A Carnot cycle requires an ideal gas for its "working substance."

Accepted Answer

A Carnot cycle can operate with any reversible working substance, not just an ideal gas; it is defined by its ideal, reversible processes, not the specific type of working substance.

Question 10

Change in internal energy is

Accepted Answer

The change in internal energy in a thermodynamic system is given by the first law of thermodynamics, which states that the change in internal energy (ΔU) is equal to the heat added to the system (Q) minus the work done by the system (W), hence ΔU = Q - W.

Question 11

The First Law of Thermodynamics is equivalent to

Accepted Answer

The First Law of Thermodynamics states that energy cannot be created or destroyed in an isolated system, which is equivalent to the law of conservation of energy.

Question 12

A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle.

If the process was carried out in a clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-2, then the change of internal energy over the full cycle

Accepted Answer

The answer of A cyclic process is carried out on...

Question 13

The change of the internal energy of an ideal gas depends upon

Accepted Answer

The internal energy of an ideal gas depends only on its temperature, according to the kinetic theory of gases. Changes in volume or pressure do not directly affect the internal energy unless they result in a temperature change.

Question 14

A substance is taken through the illustrated cycle in Figure 12-3 from (p₁,v₁) to (3 p1,2 v1) to (p1,2 v1) back to (p1, v1). How much work was done?

Accepted Answer

The answer of A substance is taken through the illustrated...

Question 15

A cyclic process is carried out on an ideal gas such that it returns to its initial
State at the end of a cycle.
 
If the process was carried out on a clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-4, then that area represents

Accepted Answer

The answer of A cyclic process is carried out on...

Question 16

A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle.
 
 If the process was carried out in a counter-clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-5, then that area represents

Accepted Answer

The answer of A cyclic process is carried out on...

Question 17

A gas is confined to a rigid container that cannot expand as heat energy is added to it. This process is

Accepted Answer

Isometric processes involve a constant volume, which matches the description of a gas in a rigid container that cannot expand.

Question 18

A gas is allowed to expand at constant pressure as heat is added to it. This process is

Accepted Answer

Isobaric processes occur at a constant pressure, which matches the description of the gas expanding as heat is added to it.

Question 19

The process shown on the p-V graph in Figure 12-6 is an

Accepted Answer

The answer of The process shown on the p-V graph...

Question 20

The process shown on the p-V graph in Figure 12-7 is an

Accepted Answer

The answer of The process shown on the p-V graph...

Quiz 12: Thermodynamics

Two processes are shown on the p-V graph in Figure 12-1; one is an adiabat and the other is an isotherm. Is the process represented by the upper curve an adiabat or an isotherm?

Why don't we use "efficiency" for rating refrigerators, like we rate engines, instead of the Coefficient of Performance?

Is it possible for heat to travel from a cold object to a hotter object?

We say that energy cannot be created nor destroyed, yet a heat pump usually delivers more energy (heat) into the house than it receives from the power source (electricity, gas, etc). Why is this not a violation of the law of conservation of energy?

Both the refrigerator and the heat pump take in heat and expel it at a higher temperature. Why don't they have the same Coefficient of Performances?

As a system loses the ability to do work, its entropy decreases.

Entropy is a measure of order. The more order there is, the higher the system's entropy.

Entropy of the universe is increasing.

A Carnot cycle requires an ideal gas for its "working substance."

Change in internal energy is

The First Law of Thermodynamics is equivalent to

A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle. If the process was carried out in a clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-2, then the change of internal energy over the full cycle

The change of the internal energy of an ideal gas depends upon

A substance is taken through the illustrated cycle in Figure 12-3 from (p₁,v₁) to (3 p1,2 v1) to (p1,2 v1) back to (p1, v1) . How much work was done?

A cyclic process is carried out on an ideal gas such that it returns to its initial State at the end of a cycle. If the process was carried out on a clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-4, then that area represents

A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle. If the process was carried out in a counter-clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-5, then that area represents

A gas is confined to a rigid container that cannot expand as heat energy is added to it. This process is

A gas is allowed to expand at constant pressure as heat is added to it. This process is

The process shown on the p-V graph in Figure 12-6 is an

The process shown on the p-V graph in Figure 12-7 is an

Quiz 12: Thermodynamics

Two processes are shown on the p-V graph in Figure 12-1; one is an adiabat and the other is an isotherm. Is the process represented by the upper curve an adiabat or an isotherm?

Why don't we use "efficiency" for rating refrigerators, like we rate engines, instead of the Coefficient of Performance?

Is it possible for heat to travel from a cold object to a hotter object?

We say that energy cannot be created nor destroyed, yet a heat pump usually delivers more energy (heat) into the house than it receives from the power source (electricity, gas, etc). Why is this not a violation of the law of conservation of energy?

Both the refrigerator and the heat pump take in heat and expel it at a higher temperature. Why don't they have the same Coefficient of Performances?

As a system loses the ability to do work, its entropy decreases.

Entropy is a measure of order. The more order there is, the higher the system's entropy.

Entropy of the universe is increasing.

A Carnot cycle requires an ideal gas for its "working substance."

Change in internal energy is

The First Law of Thermodynamics is equivalent to

A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle. If the process was carried out in a clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-2, then the change of internal energy over the full cycle

The change of the internal energy of an ideal gas depends upon

A substance is taken through the illustrated cycle in Figure 12-3 from (p1,v1) to (3 p1,2 v1) to (p1,2 v1) back to (p1, v1) . How much work was done?

A cyclic process is carried out on an ideal gas such that it returns to its initial State at the end of a cycle. If the process was carried out on a clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-4, then that area represents

A cyclic process is carried out on an ideal gas such that it returns to its initial state at the end of a cycle. If the process was carried out in a counter-clockwise sense around the enclosed area, as shown on the p-V diagram in Figure 12-5, then that area represents

A gas is confined to a rigid container that cannot expand as heat energy is added to it. This process is

A gas is allowed to expand at constant pressure as heat is added to it. This process is

The process shown on the p-V graph in Figure 12-6 is an

The process shown on the p-V graph in Figure 12-7 is an

A substance is taken through the illustrated cycle in Figure 12-3 from (p₁,v₁) to (3 p1,2 v1) to (p1,2 v1) back to (p1, v1) . How much work was done?