Kinetic Theory of Gases and Radiation — Class 12 Maharashtra HSC Physics revision notes
A 6-page visual revision sheet for Kinetic Theory of Gases and Radiation, written for Class 12 Maharashtra HSC Physics. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
Page 1 as PDF
Kinetic Theory of Gases and Radiation in one look
molecules make pressure, temperature is energy, and hot things glow
The gas laws and the ideal gas equation
- Boyle, at constant T
V ∝ 1/P - Charles, at constant P
V ∝ T - Gay-Lussac, at constant V
P ∝ T - combined, for a fixed mass
P_1V_1/T_1 = P_2V_2/T_2 - ideal gas equation
PV = nRT - per molecule
PV = Nk_BT,quad R = N_Ak_B
The assumptions behind the model
- ~10^23 molecules a mole: tracking one is hopeless, so the theory averages over all
- spread uniformly, moving randomly in straight lines at constant velocity between collisions
- collisions perfectly elastic, with each other and the walls: kinetic energy conserved
- force only during a collision; the collision time itself negligible
- ignoring molecule-molecule collisions for pressure is fair: the mean free path grows as P drops
Ideal gas vs real gas
- obeys PV = nRT at every pressure and temperature
- no intermolecular interactions at all
- point molecules, no volume of their own
- molecules do interact, so no real gas is truly ideal
- close to ideal at low density: low pressure or high temperature
- and well above its liquefaction temperature
Page 1 of 6. The full sheet, all 6 pages, opens free in the app.
What this Kinetic Theory of Gases and Radiation sheet covers
- ideal gas
- gas laws
- The gas laws and the ideal gas equation
- Boyle, at constant T
- Charles, at constant P
- Gay-Lussac, at constant V
- combined, for a fixed mass
- ideal gas equation
- per molecule
- The assumptions behind the model
- Ideal gas vs real gas
- Ideal
- Real
- mean free path
- definition
- using the gas equation
- nitrogen at 0 ° C and 1 atm
- pressure exerted by molecules
- Pressure of an ideal gas
- Pressure, one molecule and many
- rms speed
- Root mean square speed
- from the pressure equation
- speed of sound in a gas
- Temperature is kinetic energy
- degrees of freedom
- equipartition
- Law of equipartition of energy
- Mayer's relation and the specific heats
- heat at constant volume
- heat at constant pressure
- Mayer's relation, per mole
- with heat in calories
- in principal specific heats
- Specific heats from the degrees of freedom
- heat radiation
- absorption
- Absorption, reflection and transmission
- the three shares add up
- coefficient of absorption
- coefficient of reflection
- coefficient of transmission
- Diathermanous and athermanous
- Diathermanous
- Athermanous
- blackbody
- Ferry
- Perfect blackbody
- Emission, emissive power and emissivity
- Kirchhoff's law of heat radiation
- Spectral distribution of blackbody radiation
- Wien
- Wien's displacement law
- the law
- Wien's constant
- Stefan
- Stefan-Boltzmann law
- ordinary body
- net loss in surroundings at T_0
- Stefan's constant
- Stefan-Boltzmann, the special forms
- Symbols, units and dimensions
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Physics chapter by chapter against your real exam dates and free hours, and when the plan reaches Kinetic Theory of Gases and Radiation the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.
More Physics Class 12 revision notes
- AC Circuits
- Current Electricity
- Dual Nature of Radiation and Matter
- Electromagnetic Induction
- Electrostatics
- Magnetic Fields due to Electric Current
- Magnetic Materials
- Mechanical Properties of Fluids
- Oscillations
- Rotational Dynamics
- Semiconductor Devices
- Structure of Atoms and Nuclei
- Superposition of Waves
- Thermodynamics
- Wave Optics