Class 11 · Physics · English medium · Part 2
Class 11 Physics Part 2 companion
An interactive companion to Class 11 Physics Part 2: original explanations, simulations, derivations, worked numericals and practice for matter, heat, oscillations and waves.
An original companion to Physics, NCERT Class 11 Physics (2026–27 edition). Official textbook ↗ ncert.nic.in
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Chapters
- ENHinglish
Chapter 8: Mechanical Properties of Solids
Class 11 Physics chapter 8. - ENHinglish
Chapter 9: Mechanical Properties of Fluids
Class 11 Physics chapter 9 (Part 2). - ENHinglish
Chapter 10: Thermal Properties of Matter
Class 11 Physics chapter 10 distinguishes temperature from heat, builds the Celsius, Fahrenheit and Kelvin scales (gas thermometer, absolute - ENHinglish
Chapter 11: Thermodynamics
This chapter builds thermodynamics from bulk variables. - ENHinglish
Chapter 12: Kinetic Theory
Class 11 Physics chapter 12 (NCERT Part 2). - ENHinglish
Chapter 13: Oscillations
Class 11 Physics chapter 13 (Part 2) studies periodic and oscillatory motion and, above all, simple harmonic motion. - ENHinglish
Chapter 14: Waves
Class 11 Physics chapter 14 treats mechanical waves: travelling disturbances in an elastic medium that carry energy, not matter.
Also in Hinglish
- Chapter 8: Solids ki Mechanical Properties (Hinglish)
- Chapter 9: Fluids ki Mechanical Properties (Hinglish)
- Chapter 10: Matter ki Thermal Properties (Hinglish)
- Chapter 11: Thermodynamics (Hinglish)
- Chapter 12: Kinetic Theory (Hinglish)
- Chapter 13: Oscillations (Hinglish)
- Chapter 14: Waves (Hinglish)
A
absolute zeroपरम शून्यThe lowest possible temperature, 0 K or −273.15 °C, where an ideal gas would exert no pressure.Ch 10 · Thermal Properties of Matteradiabatic processरुद्धोष्म प्रक्रमA process with no heat exchange; for a quasi-static ideal gas PV γ stays constant.Ch 11 · ThermodynamicsamplitudeआयामThe largest magnitude of the displacement from equilibrium in an oscillation, A.Ch 13 · OscillationsamplitudeआयामThe largest displacement of a particle of the medium from its equilibrium position; always positive.Ch 14 · Wavesangle of contactस्पर्श कोणThe angle between a solid surface and the tangent to a liquid surface where they meet, measured through the liquid.Ch 9 · Mechanical Properties of Fluidsangular frequencyकोणीय आवृत्तिω = 2 π/T = 2 π ν, in radians per second.Ch 13 · Oscillationsangular wave numberकोणीय तरंग संख्याk = 2 π/λ, the phase change per unit length; SI unit rad m⁻¹.Ch 14 · Wavesantinodeप्रस्पंदA point of a standing wave with the largest amplitude, midway between two nodes.Ch 14 · WavesAvogadro numberआवोगाद्रो संख्याThe number of particles in one mole, NA ≈ 6.02 × 10²³.Ch 12 · Kinetic TheoryB
beatsविस्पंदThe regular rise and fall in loudness heard when two sounds of slightly different frequencies combine, at ν1 - ν2 per second.Ch 14 · WavesBernoulli's principleबरनौली का सिद्धांतAlong a streamline of an ideal fluid in steady flow, P + 12 ρ v² + ρ g h is constant.Ch 9 · Mechanical Properties of FluidsBoltzmann constantबोल्ट्ज़मान नियतांकThe gas constant per molecule, kB = R/NA = 1.38 × 10⁻²³ J/K.Ch 12 · Kinetic Theorybulk modulusआयतन गुणांकThe ratio of hydraulic stress to volume strain, B = -p/(Δ V/V); defined for solids, liquids and gases.Ch 8 · Mechanical Properties of SolidsC
capillary riseकेशिकत्वRise or fall of a liquid in a narrow tube caused by surface tension: h = 2S cos θ/ρ g a.Ch 9 · Mechanical Properties of FluidsCarnot engineकार्नो इंजनA reversible engine working between two reservoirs through two isothermal and two adiabatic steps; its efficiency is 1 - T2/T1.Ch 11 · Thermodynamicscoefficient of linear expansionरैखिक प्रसार गुणांकFractional increase in length per kelvin, αl = Δ l/(l Δ T).Ch 10 · Thermal Properties of Mattercoefficient of volume expansionआयतन प्रसार गुणांकFractional increase in volume per kelvin, αV = Δ V/(V Δ T); for an isotropic solid αV = 3 αl.Ch 10 · Thermal Properties of Mattercompressibilityसंपीड्यताThe reciprocal of the bulk modulus: the fractional decrease in volume per unit increase in pressure.Ch 8 · Mechanical Properties of SolidsconvectionसंवहनHeat transfer by the bulk flow of a fluid, driven by buoyancy (natural) or by a pump or fan (forced).Ch 10 · Thermal Properties of MatterD
degree of freedomस्वातंत्र्य कोटिAn independent way a molecule can move; in energy counting, each squared term in its energy.Ch 12 · Kinetic Theorydiathermic wallA wall that lets heat pass, such as a thin copper sheet. A wall that blocks heat is called adiabatic.Ch 11 · Thermodynamicsductileतन्यAble to stretch a long way plastically before breaking, like copper; a brittle material, like glass, breaks soon after its elastic limit.Ch 8 · Mechanical Properties of SolidsE
elastic limitप्रत्यास्थता सीमाThe greatest stress a material can bear and still recover fully; the stress at this yield point is the yield strength.Ch 8 · Mechanical Properties of Solidselasticityप्रत्यास्थताThe property of a body that makes it return to its original size and shape when the deforming forces are removed.Ch 8 · Mechanical Properties of SolidselastomerA material, such as rubber, that stretches elastically to very large strains but does not obey Hooke's law.Ch 8 · Mechanical Properties of Solidsemissivityउत्सर्जकताThe ratio of the radiation a surface emits to that of a blackbody at the same temperature, between 0 and 1.Ch 10 · Thermal Properties of Matterequation of continuityसांतत्य समीकरणFor steady flow of an incompressible fluid, Av is the same at every cross-section; it expresses mass conservation.Ch 9 · Mechanical Properties of FluidsF
first law of thermodynamicsEnergy conservation for a system: heat supplied equals the rise in internal energy plus the work done by the system, Δ Q = Δ U + Δ W.Ch 11 · ThermodynamicsfluidतरलA substance that can flow: a liquid or a gas. At rest it cannot support a shear stress.Ch 9 · Mechanical Properties of Fluidsfrequencyआवृत्तिThe number of repeats per second, ν = 1/T, measured in hertz (Hz).Ch 13 · OscillationsG
gauge pressureप्रमापी दाबPressure above atmospheric pressure, P - Pa; what tyre gauges and manometers read.Ch 9 · Mechanical Properties of FluidsH
heatऊष्माEnergy transferred because of a temperature difference, measured in joules.Ch 10 · Thermal Properties of Matterheatऊष्माEnergy that flows between a system and its surroundings because of a temperature difference.Ch 11 · ThermodynamicsI
ideal gasआदर्श गैसA model gas that obeys PV = μ RT exactly; real gases approach it at low pressure and high temperature.Ch 12 · Kinetic Theoryinterferenceव्यतिकरणThe combined effect of overlapping waves: reinforcement when in phase, cancellation when opposite in phase.Ch 14 · Wavesinternal energyआंतरिक ऊर्जाThe total kinetic and potential energy of the molecules of a system, measured in the frame where the system as a whole is at rest; symbol U.Ch 11 · Thermodynamicsisothermal processसमतापीय प्रक्रमA process at constant temperature; for an ideal gas PV stays constant and Δ U = 0.Ch 11 · ThermodynamicsK
kinetic theoryअणुगति सिद्धांतThe model that explains the properties of a gas from the motion of its molecules, using Newton's laws and averages.Ch 12 · Kinetic TheoryL
latent heatगुप्त ऊष्माHeat per unit mass taken in or given out in a change of state at constant temperature, L = Q/m.Ch 10 · Thermal Properties of Matterlaw of equipartition of energyऊर्जा के समविभाजन का नियमIn thermal equilibrium each squared term in a molecule's energy has an average of 12 kBT.Ch 12 · Kinetic Theorylinear harmonic oscillatorरैखिक आवर्ती दोलित्रA body acted on by a restoring force exactly proportional to its displacement.Ch 13 · Oscillationslongitudinal waveअनुदैर्ध्य तरंगA wave in which the particles move along the direction of travel, forming compressions and rarefactions.Ch 14 · WavesM
mean free pathमाध्य मुक्त पथThe average distance a molecule travels between collisions, l = 1/(√ 2 n π d²).Ch 12 · Kinetic Theorymodulus of elasticityप्रत्यास्थता गुणांकThe ratio of stress to strain where Hooke's law holds; a property of the material.Ch 8 · Mechanical Properties of Solidsmolar specific heat capacityमोलर विशिष्ट ऊष्मा धारिताHeat needed per mole per kelvin; for a gas CP exceeds CV.Ch 10 · Thermal Properties of Mattermolar specific heat capacityHeat needed per mole per kelvin rise in temperature, C = Δ Q/(μ Δ T), in J mol⁻¹ K⁻¹.Ch 11 · Thermodynamicsmolar specific heat capacityमोलर विशिष्ट ऊष्मा धारिताHeat needed to warm one mole by one kelvin: Cv at constant volume, Cp at constant pressure.Ch 12 · Kinetic TheoryN
nodeनिस्पंदA point of a standing wave that never moves (zero amplitude).Ch 14 · Wavesnormal modeA natural frequency at which a bounded system (string, air column) can vibrate in a standing wave; the lowest is the fundamental.Ch 14 · WavesO
oscillatory motionदोलन गतिPeriodic to-and-fro motion about an equilibrium position, caused by a force that points back towards it.Ch 13 · OscillationsP
partial pressureआंशिक दाबThe pressure one gas in a mixture would exert if it alone filled the container at the same temperature.Ch 12 · Kinetic TheoryPascal's lawपास्कल का नियमIn a fluid at rest pressure acts equally in all directions, is the same on a level, and a change in it is passed on undiminished.Ch 9 · Mechanical Properties of Fluidsperiodआवर्तकालThe least time after which a periodic motion repeats, T; SI unit second.Ch 13 · Oscillationsperiodic motionआवर्ती गतिMotion that repeats itself exactly after equal intervals of time.Ch 13 · Oscillationspermanent setThe strain that remains when a body stressed beyond its elastic limit is unloaded.Ch 8 · Mechanical Properties of SolidsphaseकलाThe angle ω t + ϕ in x = A cos (ω t + ϕ), which fixes the position and direction of motion at time t.Ch 13 · OscillationsphaseकलाThe argument kx - ω t + ϕ of a harmonic wave, which fixes the displacement at a given place and time.Ch 14 · Wavesphase constantकला स्थिरांकThe value ϕ of the phase at t = 0.Ch 13 · Oscillationsplasticityसुघट्यताThe property of a material that keeps the new shape it is given after the deforming force is removed, as clay does.Ch 8 · Mechanical Properties of SolidsPoisson's ratioपॉयसन अनुपातLateral strain divided by longitudinal strain in a stretched body; a pure number, about 0.3 for metals.Ch 8 · Mechanical Properties of SolidspressureदाबNormal force per unit area at a point in a fluid; a scalar, measured in pascal (Pa).Ch 9 · Mechanical Properties of Fluidsprinciple of superpositionअध्यारोपण का सिद्धांतWhere waves overlap, the displacement at each point equals the sum, with signs, of the displacements each wave would cause alone.Ch 14 · Wavesprogressive waveप्रगामी तरंगA wave whose pattern moves through the medium, carrying energy with it.Ch 14 · WavesQ
quasi-static processस्थैतिककल्प प्रक्रमAn idealised, infinitely slow process in which the system passes only through equilibrium states.Ch 11 · ThermodynamicsR
reference circleनिर्देश वृत्तA circle round which a particle moves uniformly; its projection on a diameter performs SHM.Ch 13 · Oscillationsregelationपुनर्हिमायनMelting of ice under pressure and refreezing when the pressure is removed.Ch 10 · Thermal Properties of Matterrelative densityआपेक्षिक घनत्वDensity of a substance divided by the density of water at 4 °C; it has no unit.Ch 9 · Mechanical Properties of Fluidsrestoring forceप्रत्यानयन बलA force that always points back towards the equilibrium position; in SHM it is -kx.Ch 13 · Oscillationsreversible processउत्क्रमणीय प्रक्रमA process that can be run backwards so that the system and surroundings both return to their starting states with no change elsewhere.Ch 11 · Thermodynamicsrms speedवर्ग-माध्य-मूल चालThe square root of the mean of the squared molecular speeds, vrms = √ 3kBT/m.Ch 12 · Kinetic TheoryS
shear modulusअपरूपण गुणांकThe ratio of shearing stress to shearing strain, G = F/(A θ).Ch 8 · Mechanical Properties of Solidssimple harmonic motionसरल आवर्त गतिOscillation in which the displacement is a sinusoidal function of time, produced by a force F = -kx.Ch 13 · Oscillationssimple pendulumसरल लोलकA point-like bob on a light, inextensible string; for small swings T = 2 π √ L/g.Ch 13 · Oscillationsspecific heat capacityविशिष्ट ऊष्मा धारिताHeat needed to warm 1 kg of a substance by 1 K, in J kg⁻¹ K⁻¹.Ch 10 · Thermal Properties of Matterspecific heat capacityविशिष्ट ऊष्मा धारिताHeat needed per unit mass per kelvin rise in temperature, s = Δ Q/(m Δ T), in J kg⁻¹ K⁻¹.Ch 11 · Thermodynamicsspring constantस्प्रिंग नियतांकThe force per unit extension of a spring, k, in N/m; in SHM k = m ω².Ch 13 · Oscillationsstanding waveअप्रगामी तरंगThe pattern 2a sin kx cos ω t formed by two identical waves travelling in opposite directions; it does not move along the medium.Ch 14 · Wavesstate variableअवस्था चरA quantity such as P, V, T or U whose value is fixed by the equilibrium state alone, not by how the state was reached.Ch 11 · ThermodynamicsstrainविकृतिThe fractional change in a dimension of a body (length, angle of shear or volume); it has no unit.Ch 8 · Mechanical Properties of SolidsstreamlineधारारेखाThe path of fluid particles in steady flow; its tangent gives the fluid's velocity at each point.Ch 9 · Mechanical Properties of Fluidsstressप्रतिबलThe restoring force per unit area inside a deformed body, F/A, measured in pascals.Ch 8 · Mechanical Properties of Solidssublimationऊर्ध्वपातनA direct change from solid to vapour, as in dry ice or camphor.Ch 10 · Thermal Properties of Mattersurface tensionपृष्ठ तनावForce per unit length in a liquid surface, equal to its extra energy per unit area; unit N m⁻¹.Ch 9 · Mechanical Properties of FluidsT
temperatureतापA number on an agreed scale that says how hot a body is; heat flows from higher to lower temperature.Ch 10 · Thermal Properties of Matterterminal velocityसीमांत वेगThe steady speed a body reaches falling through a fluid, when drag and buoyancy balance its weight.Ch 9 · Mechanical Properties of Fluidsthermal conductivityऊष्मा चालकताThe constant K in H = KA Δ T/L; how well a material conducts heat, in W m⁻¹ K⁻¹.Ch 10 · Thermal Properties of Matterthermal equilibriumतापीय साम्यThe state of two systems in thermal contact when no net heat flows between them, so their macroscopic variables stop changing.Ch 11 · Thermodynamicsthermal stressतापीय प्रतिबलStress in a body that is heated or cooled but not allowed to change size; Y αl Δ T for a clamped rod.Ch 10 · Thermal Properties of Matterthermodynamicsऊष्मागतिकीThe branch of physics that relates heat, work, temperature and energy using a few measurable bulk variables.Ch 11 · Thermodynamicstransverse waveअनुप्रस्थ तरंगA wave in which the particles of the medium move at right angles to the direction of travel.Ch 14 · Wavestriple pointत्रिक बिंदुThe single temperature and pressure at which solid, liquid and vapour coexist; for water 273.16 K and 611.66 Pa.Ch 10 · Thermal Properties of Matterturbulent flowविक्षुब्ध प्रवाहIrregular flow beyond a critical speed, in which the velocity at a point fluctuates and eddies form.Ch 9 · Mechanical Properties of FluidsU
ultimate tensile strengthThe greatest stress a material reaches in a tensile test, after which it necks and breaks.Ch 8 · Mechanical Properties of SolidsV
viscosityश्यानताInternal friction between fluid layers in relative motion; η is shear stress divided by strain rate, in Pa s.Ch 9 · Mechanical Properties of FluidsW
waveतरंगA travelling disturbance that carries energy from place to place while the medium only oscillates about fixed positions.Ch 14 · Waveswavelengthतरंगदैर्ध्यThe smallest distance between two points in the same phase at one instant, λ = 2 π/k.Ch 14 · WavesY
Young's modulusयंग गुणांकThe ratio of longitudinal stress to longitudinal strain, Y = FL/(A Δ L).Ch 8 · Mechanical Properties of SolidsZ
zeroth law of thermodynamicsIf two systems are each in thermal equilibrium with a third, they are in thermal equilibrium with each other.Ch 11 · Thermodynamicsncert.ai is an independent learning companion aligned to the NCERT curriculum. It is not affiliated with or endorsed by NCERT.