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B.2 – Thermodynamics

Path:

Option B: Engineering physics » Option B: Engineering physics (Core topics) » B.2 – Thermodynamics

Description

Nature of science:

Variety of perspectives: With three alternative and equivalent statements of the second law of thermodynamics, this area of physics demonstrates the collaboration and testing involved in confirming abstract notions such as this. (4.1)

Understandings:

The first law of thermodynamics
The second law of thermodynamics
Entropy
Cyclic processes and pV diagrams
Isovolumetric, isobaric, isothermal and adiabatic processes
Carnot cycle
Thermal efficiency

Applications and skills:

Describing the first law of thermodynamics as a statement of conservation of energy
Explaining sign convention used when stating the first law of thermodynamics as
Solving problems involving the first law of thermodynamics
Describing the second law of thermodynamics in Clausius form, Kelvin form and as a consequence of entropy
Describing examples of processes in terms of entropy change
Solving problems involving entropy changes
Sketching and interpreting cyclic processes
Solving problems for adiabatic processes for monatomic gases using = constant
Solving problems involving thermal efficiency

Guidance:

If cycles other than the Carnot cycle are used quantitatively, full details will be provided
Only graphical analysis will be required for determination of work done on a pVdiagram when pressure is not constant

Data booklet reference:

International-mindedness:

The development of this topic was the subject of intense debate between scientists of many countries in the 19th century

Utilization:

This work leads directly to the concept of the heat engines that play such a large role in modern society
The possibility of the heat death of the universe is based on ever-increasing entropy
Chemistry of entropy (see Chemistry sub-topic 15.2)

Aims:

Aim 5: development of the second law demonstrates the collaboration involved in scientific pursuits
Aim 10: the relationships and similarities between scientific disciplines are particularly apparent here

Directly related questions

16N.3.SL.TZ0.10a:
Calculate the Carnot efficiency of the nuclear power plant.
16N.3.SL.TZ0.10c:
The nuclear power plant works at 71.0% of the Carnot efficiency. The power produced is 1.33 GW. Calculate how much waste thermal energy is released per hour.
16N.3.SL.TZ0.10b:
Explain, with a reason, why a real nuclear power plant operating between the stated temperatures cannot reach the efficiency calculated in (a).
16N.3.SL.TZ0.10d: Discuss the production of waste heat by the power plant with reference to the first law and the...
17M.3.SL.TZ1.6a:
State what is meant by an adiabatic process.
17M.3.SL.TZ1.6c.i:
Determine the temperature of the gas at A.
17M.3.SL.TZ1.6c.ii:
The volume at B is 2.30 × 10^–3 $\,$ m³. Determine the pressure at B.
17M.3.SL.TZ1.6d.ii:
The volume at C is 2.90 × 10^–3 $\,$ m³. Calculate the temperature at C.
17M.3.SL.TZ1.6e:
State a reason why a Carnot cycle is of little use for a practical heat engine.
17M.3.SL.TZ1.6d.i:
Show that ${P_B}V_B^{\frac{5}{3}} = nR{T_C}V_C^{\frac{2}{3}}$
17M.3.SL.TZ1.6b:
Identify the two isothermal processes.
17M.3.SL.TZ2.7b:
State and explain at which point in the cycle ABCA the entropy of the gas is the largest.
17M.3.SL.TZ2.7a.ii:
Show that the temperature of the gas at C is 386 K.
17M.3.SL.TZ2.7a.iii:
Show that the thermal energy removed from the gas for the change BC is approximately 330 J.
17M.3.SL.TZ2.7a.iv:
Determine the efficiency of the heat engine.
17M.3.SL.TZ2.7a.i:
Justify why the thermal energy supplied during the expansion AB is 416 J.
20N.3.SL.TZ0.9b(i):
Calculate the pressure following this process.
20N.3.SL.TZ0.9a(i):
Calculate the work done during the compression.
20N.3.SL.TZ0.9a(ii):
Calculate the work done during the increase in pressure.
20N.3.SL.TZ0.9b(ii): Outline how an approximate adiabatic change can be achieved.
17N.3.SL.TZ0.10c:
The final image of the Moon is observed through the eyepiece. The focal length of the eyepiece is 5.0 cm. Calculate the magnification of the telescope.
17N.3.SL.TZ0.8b: Using the axes, sketch the three-step cycle.
17N.3.SL.TZ0.8a:
Show that the volume of the gas at the end of the adiabatic expansion is approximately 5.3 x 10^–3 m³.
17N.3.SL.TZ0.8d:
Using your sketched graph in (b), identify the feature that shows that net work is done by the gas in this three-step cycle.
17N.3.SL.TZ0.8c:
The initial temperature of the gas is 290 K. Calculate the temperature of the gas at the start of the adiabatic expansion.
18M.3.SL.TZ2.7d.ii:
Outline the change in entropy of the gas during the cooling at constant volume.
18M.3.SL.TZ2.7b:
Calculate, in J, the work done by the gas during this expansion.
18M.3.SL.TZ2.7e:
There are various equivalent versions of the second law of thermodynamics. Outline the benefit gained by having alternative forms of a law.
18M.3.SL.TZ2.7a:
Show that the final volume of the gas is about 53 m³.
18M.3.SL.TZ2.7c:
Determine the thermal energy which enters the gas during this expansion.
18M.3.SL.TZ2.7d.i:
Sketch, on the pV diagram, the complete cycle of changes for the gas, labelling the changes clearly. The expansion shown in (a) and (b) is drawn for you.
18M.3.SL.TZ1.7a:
Show that the pressure at B is about 5 × 10⁵ Pa.
18M.3.SL.TZ1.7b.i:
For the process BC, calculate, in J, the work done by the gas.
18M.3.SL.TZ1.7b.ii:
For the process BC, calculate, in J, the change in the internal energy of the gas.
18M.3.SL.TZ1.7b.iii:
For the process BC, calculate, in J, the thermal energy transferred to the gas.
18M.3.SL.TZ1.7c.i:
Explain, without any calculation, why the pressure after this change would belower if the process was isothermal.
18M.3.SL.TZ1.7c.ii:
Determine, without any calculation, whether the net work done by the engine during one full cycle would increase or decrease.
18M.3.SL.TZ1.7d:
Outline why an efficiency calculation is important for an engineer designing a heat engine.
18N.3.SL.TZ0.7b:
Show that the thermal energy transferred from the gas during the change B → C is 238 J.
18N.3.SL.TZ0.7c.i:
The work done by the gas from A → B is 288 J. Calculate the efficiency of the cycle.
18N.3.SL.TZ0.7a.ii:
Show that at C the temperature is 254 K.
18N.3.SL.TZ0.7a.i:
Show that at C the pressure is 1.00 × 10⁶Pa.
18N.3.SL.TZ0.7c.ii:
State, without calculation, during which change (A → B, B → C or C → A) the entropy of the gas decreases.
19M.3.SL.TZ2.10c: Determine, using the first law of thermodynamics, the total thermal energy transferred to the...
19M.3.SL.TZ2.10bii: Calculate the temperature at A if the temperature at B is −40°C.
19M.3.SL.TZ2.10d: Suggest why this cycle is not a suitable model for a working heat pump.
19M.3.SL.TZ2.10a:
Show that the work done on the gas for the isothermal process C→A is approximately 440 J.
19M.3.SL.TZ2.10bi:
Calculate the change in internal energy of the gas for the process A→B.
19N.3.SL.TZ0.6b(iii): state and explain whether the second law of thermodynamics is violated.
19N.3.SL.TZ0.6b(i):
determine the thermal energy removed from the system.
19N.3.SL.TZ0.6a(ii):
Calculate the ratio $\frac{V_{A}}{V_{C}}$ .
19N.3.SL.TZ0.6b(ii):
explain why the entropy of the gas decreases.
19N.3.SL.TZ0.6a(i):
Show that the pressure at B is about 130 kPa.

Sub sections and their related questions

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DP Physics Questionbank

B.2 – Thermodynamics

Description

Directly related questions

Sub sections and their related questions