Thermodynamics | Edexcel A-Level Physics (9PH0)

Thermodynamics

96 questions
10 subtopics
Paper 2: Advanced Physics II
Paper 2 and Paper 3

Paper 2 content on heating and gases: specific heat capacity and specific latent heat and how each is measured, internal energy and the absolute temperature scale, the kinetic theory of an ideal gas and its derivation, and black body radiation with Wien's and Stefan-Boltzmann's laws..

It covers specific heat capacity and specific latent heat, measuring specific heat capacity and calibrating a thermistor, measuring specific latent heat, internal energy, temperature and absolute zero, mean kinetic energy and the absolute temperature scale, the kinetic theory equation and its derivation, the ideal gas equation and molecular kinetic energy, boyle's law and investigating a fixed mass of gas, black body radiation and Wien's law and the Stefan-Boltzmann law and stellar calculations.

Sample questions from Thermodynamics

Answer each one closed book first, then open the answer.

Specific heat capacity and specific latent heat

What is meant by the specific latent heat of a substance?

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It is the energy needed to change the state of 1 kg of the substance without any change in temperature.
Measuring specific heat capacity and calibrating a thermistor

What two steps would reduce heat losses when measuring a specific heat capacity?

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Lag the block or container with insulation, and keep the temperature rise small so the sample spends less time above room temperature.
Measuring specific latent heat

How can the specific latent heat of fusion of ice be found using an electrical heater?

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Place an immersion heater of known power in a funnel packed with melting ice, collect and weigh the melt water produced in a measured time, then use L = Pt/Δm.
Internal energy, temperature and absolute zero

What happens to the internal energy of a solid as it melts at a constant temperature?

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The internal energy increases because the molecular potential energy rises as bonds are broken, while the mean molecular kinetic energy stays the same.
Mean kinetic energy and the absolute temperature scale

A gas is heated from 27 °C to 327 °C. By what factor does the mean kinetic energy of its molecules increase?

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The absolute temperature rises from 300 K to 600 K, so the mean kinetic energy doubles.
The kinetic theory equation and its derivation

State the equation that defines pressure in terms of force and area:

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Pressure is given by p = F/A, the force acting normally per unit area.
The ideal gas equation and molecular kinetic energy

How many molecules are there in 2.0 × 10⁻³ m³ of gas at a pressure of 1.0 × 10⁵ Pa and a temperature of 300 K?

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N = pV/kT = (1.0 × 10⁵ × 2.0 × 10⁻³)/(1.38 × 10⁻²³ × 300) = 4.8 × 10²² molecules.
Boyle's law and investigating a fixed mass of gas

What does Boyle's law state?

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For a fixed mass of gas at constant temperature, the pressure is inversely proportional to the volume.

The 10 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Specific heat capacity and specific latent heat	Recall questions on both definitions and their units, the two energy equations, why temperature stays constant during a change of state, and why vaporisation takes more energy than fusion.	12
Measuring specific heat capacity and calibrating a thermistor	Recall questions on the electrical method and why it reads high, reducing heat losses, and calibrating a thermistor in a potential divider as a thermometer.	8
Measuring specific latent heat	Recall questions on the funnel-and-heater method for ice, why a second control funnel is used, the boiling-liquid method, and reading a heating curve.	8
Internal energy, temperature and absolute zero	Recall questions on what internal energy is, the two molecular contributions, what temperature tells you about molecules, and the meaning of absolute zero.	10
Mean kinetic energy and the absolute temperature scale	Recall questions on the link between mean kinetic energy and absolute temperature, converting from Celsius, why the absolute scale must be used, and why a gas cools as a liquid evaporates.	10
The kinetic theory equation and its derivation	Recall questions on pV = ⅓Nm⟨c²⟩ and what each symbol means, the four assumptions of the model, and the steps from one molecule in a cube to the pressure on a wall.	10
The ideal gas equation and molecular kinetic energy	Recall questions on pV = NkT and the Boltzmann constant, combining it with the kinetic theory equation, and comparing two gases held at the same temperature.	9
Boyle's law and investigating a fixed mass of gas	Recall questions on the statement of Boyle's law, why pressure must be changed slowly, why a column length can stand in for volume, and which graph confirms the law.	8
Black body radiation and Wien's law	Recall questions on what a black body radiator is, the shape of the radiation curve and how it changes with temperature, and Wien's law applied to a star.	10
The Stefan-Boltzmann law and stellar calculations	Recall questions on the law and its constant, which area to use for a star, comparing stars of equal radius or equal temperature, and using both laws together.	11

Thermodynamics is 96 of the 1,616 questions in the guide.Get the guide, £8

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.