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Class 11 PhysicsChapter Summaries

15 chapters · Quick revision in under 3 minutes per chapter · Updated 2025-26

Ch 1

Physical World

Introduces the scope and excitement of physics, covering its fundamental forces and their relative strengths. Students learn about the scientific method and how physics underpins all natural phenomena. The chapter surveys major sub-fields of physics from mechanics to cosmology. It emphasises the unity of physics and the role of hypothesis, experiment, and theory.

Topics covered

Four fundamental forces: gravitational, electromagnetic, strong nuclear, weak nuclearRelative strengths and ranges of fundamental forcesNature of physical laws: conservation of energy, momentum, chargeScope of physics: macroscopic, microscopic, mesoscopicPhysics and technology: historical milestonesReductionism and unification as goals of physics

⚠️ Removed from 2025-26 syllabus

Physics, technology and society (detailed section removed from CBSE 2025-26 syllabus)

Detailed discussion of physicists' contributions and Nobel prizes (removed)

Excitement of physics — narrative portion (reduced to brief introduction only)

Ch 2

Units and Measurements

Covers the SI system of units, dimensional analysis, and significant figures. Students learn to express measurements with correct precision and use dimensional analysis for checking equations and deriving relations. Error analysis including absolute, relative, and percentage errors is a key exam topic.

Topics covered

SI base units: m, kg, s, A, K, mol, cd — definitionsDimensional formulae and dimensional equationsApplications of dimensional analysis: checking homogeneity, deriving formulasSignificant figures: rules for arithmetic operationsTypes of errors: systematic, random, gross; absolute error, relative error, percentage errorCombination of errors: addition, subtraction, multiplication, division, powersParallax method for measuring large distances; vernier calliper and screw gauge

Ch 3

Motion in a Straight Line

Introduces kinematics of a particle moving along a straight line. Students study average and instantaneous velocity, uniform and non-uniform acceleration, and the three equations of motion. Graphical analysis using position-time and velocity-time graphs is essential for board exams.

Topics covered

Equations of uniformly accelerated motion: v = u + at; s = ut + ½at²; v² = u² + 2asDisplacement in nth second: sₙ = u + a(2n−1)/2Position-time graph: slope = velocity; velocity-time graph: slope = acceleration, area = displacementRelative velocity: v_AB = v_A − v_BFree fall: a = g = 9.8 m/s² downward; terminal velocity conceptInstantaneous velocity = lim(Δt→0) Δx/Δt = dx/dt

Ch 4

Motion in a Plane

Extends kinematics to two dimensions using vectors. Students learn vector addition, subtraction, and resolution into components. Projectile motion and uniform circular motion are the two major applications. Relative velocity in 2D is also covered.

Topics covered

Vector addition: triangle law, parallelogram law; resultant magnitude and directionResolution of vectors: A_x = A cos θ, A_y = A sin θScalar (dot) product: A·B = AB cos θ; vector (cross) product: |A×B| = AB sin θProjectile motion: T = 2u sinθ/g; R = u² sin 2θ/g; H = u² sin²θ/2gMaximum range at θ = 45°; R_max = u²/gUniform circular motion: centripetal acceleration a = v²/r = ω²r; v = rωAngular velocity ω = 2π/T; relationship v = rω

Ch 5

Laws of Motion

Covers Newton's three laws of motion and their applications to everyday situations. Students study concepts of inertia, momentum, impulse, friction, and the dynamics of circular motion. Free body diagrams and solving problems involving multiple forces and constraints are central skills.

Topics covered

Newton's First Law: inertia; Newton's Second Law: F = ma; Newton's Third Law: action-reaction pairsLinear momentum: p = mv; impulse J = FΔt = ΔpConservation of linear momentum: ΣF_ext = 0 ⟹ Δp = 0Static friction f_s ≤ μ_s N; kinetic friction f_k = μ_k N; μ_s > μ_kFree body diagram: normal force, tension, friction, weightPseudo force in non-inertial framesMotion on inclined plane: a = g(sin θ − μ cos θ) for sliding

Ch 6

Work, Energy and Power

Introduces the scalar quantity work and its relationship with kinetic and potential energy. The work-energy theorem and conservation of mechanical energy are derived and applied. Elastic and inelastic collisions are analysed using energy and momentum principles.

Topics covered

Work done W = F·d = Fd cos θ; work by variable force W = ∫F dxKinetic energy KE = ½mv²; work-energy theorem: W_net = ΔKEPotential energy: gravitational PE = mgh; elastic PE = ½kx²Conservation of mechanical energy: KE + PE = constant (conservative forces)Power P = W/t = F·v; unit watts (W); 1 hp = 746 WElastic collision: both KE and momentum conserved; coefficient of restitution e = 1Perfectly inelastic collision: only momentum conserved; maximum KE loss

Ch 7

System of Particles and Rotational Motion

Extends mechanics to systems of particles and rigid bodies. Concepts of centre of mass, torque, angular momentum, and moment of inertia are introduced and applied. The parallel and perpendicular axis theorems are used to calculate moment of inertia for standard shapes.

Topics covered

Centre of mass: x_cm = Σm_i x_i / Σm_i; for uniform bodies — geometric centreTorque: τ = r × F; |τ| = rF sin θ; unit N·mAngular momentum L = r × p = Iω; conservation of L when τ_ext = 0Moment of inertia I = Σm_i r_i²; I for ring = MR², disc = ½MR², rod (centre) = ML²/12Parallel axis theorem: I = I_cm + Md²; perpendicular axis theorem (laminar bodies): I_z = I_x + I_yEquations of rotational motion: ω = ω₀ + αt; θ = ω₀t + ½αt²; ω² = ω₀² + 2αθRolling without slipping: KE_total = ½mv² + ½Iω² = ½mv²(1 + k²/R²)

Ch 8

Gravitation

Covers Newton's law of universal gravitation and its applications, including satellite motion, orbital and escape velocities, and Kepler's laws. Gravitational potential energy and the variation of g with altitude and depth are also studied.

Topics covered

Newton's law of gravitation: F = Gm₁m₂/r²; G = 6.67 × 10⁻¹¹ N m² kg⁻²Acceleration due to gravity: g = GM/R²; variation with altitude g' = g(1 − 2h/R) and depth g' = g(1 − d/R)Gravitational potential energy U = −GMm/rOrbital velocity: v_o = √(GM/r) = √(gR²/(R+h)); for near orbit v_o ≈ 7.9 km/sEscape velocity: v_e = √(2GM/R) = √(2gR) ≈ 11.2 km/s for EarthKepler's three laws: law of orbits (ellipse), law of areas (equal areas in equal time), law of periods T² ∝ r³Geostationary satellite: T = 24 h, height ≈ 36,000 km above equator

Ch 9

Mechanical Properties of Solids

Studies the elastic behaviour of solid materials under stress and strain. Students learn Hooke's law, Young's modulus, Bulk modulus, and Shear modulus. Stress-strain curves reveal proportionality limit, elastic limit, yield point, and breaking point.

Topics covered

Stress = F/A (N/m²); Strain = ΔL/L (dimensionless)Hooke's Law: stress ∝ strain (within elastic limit)Young's modulus Y = (F/A)/(ΔL/L) = FL/AΔL; unit Pa (N/m²)Bulk modulus B = −VΔP/ΔV; compressibility = 1/BShear modulus (rigidity modulus) G = shear stress/shear strainStress-strain curve: proportional limit, elastic limit, yield point, ultimate stress, fractureElastic potential energy stored in a wire: U = ½ × stress × strain × volume

Ch 10

Mechanical Properties of Fluids

Covers the behaviour of fluids at rest (hydrostatics) and in motion (hydrodynamics). Pressure in fluids, Pascal's law, Archimedes' principle, and Bernoulli's theorem are derived and applied. Surface tension, capillarity, and viscosity complete the chapter.

Topics covered

Pressure: P = F/A; pressure in a fluid: P = P₀ + ρgh; Pascal's lawArchimedes' principle: buoyant force = weight of displaced fluidEquation of continuity: A₁v₁ = A₂v₂ (for incompressible flow)Bernoulli's equation: P + ½ρv² + ρgh = constantApplications of Bernoulli's theorem: venturimeter, aerofoil lift, Torricelli's theoremSurface tension T = F/L; excess pressure inside drop: ΔP = 2T/r; bubble: ΔP = 4T/rViscosity: Stokes' law F = 6πηrv; terminal velocity v_t = 2r²(ρ−σ)g/9η

Ch 11

Thermal Properties of Matter

Covers temperature measurement, thermal expansion, specific heat, calorimetry, and modes of heat transfer. Students study linear, superficial, and volumetric expansion, latent heat, Newton's law of cooling, and the mechanisms of conduction, convection, and radiation.

Topics covered

Thermal expansion: linear α = ΔL/LΔT; superficial β = 2α; volumetric γ = 3αAnomalous expansion of water: maximum density at 4°CSpecific heat capacity c = Q/mΔT; molar specific heat C = McCalorimetry: heat gained = heat lost; Q = mcΔT; latent heat Q = mLConduction: H = kA(T₁−T₂)/d; k = thermal conductivity (W/m K)Newton's law of cooling: dT/dt ∝ (T − T₀); rate of coolingStefan's law: E = σT⁴; Wien's displacement law: λ_m T = b = 2.898 × 10⁻³ m K

Ch 12

Thermodynamics

Introduces the zeroth, first, and second laws of thermodynamics. Students study various thermodynamic processes (isothermal, adiabatic, isochoric, isobaric), heat engines, refrigerators, and the concept of entropy. Carnot's cycle and its efficiency are essential board topics.

Topics covered

Zeroth law: thermal equilibrium and temperature definitionFirst law: ΔU = Q − W; sign convention for Q and WIsothermal process: ΔT = 0, ΔU = 0, Q = W; W = nRT ln(V₂/V₁)Adiabatic process: Q = 0, ΔU = −W; PVᵞ = constant; γ = C_p/C_vSecond law: Kelvin-Planck statement; Clausius statement; irreversibilityCarnot engine efficiency: η = 1 − T₂/T₁; Carnot theorem: no engine is more efficient than CarnotEntropy: ΔS = Q_rev/T; entropy increases in irreversible processes

Ch 13

Kinetic Theory

Develops the kinetic theory of gases to explain macroscopic properties (pressure, temperature, specific heat) in terms of molecular motion. Students derive the pressure of an ideal gas, the kinetic interpretation of temperature, and the law of equipartition of energy.

Topics covered

Assumptions of kinetic theory: elastic collisions, negligible volume, no intermolecular forcesPressure of ideal gas: P = ⅓ρv²_rms = ⅓(Nm/V)v²_rmsrms speed: v_rms = √(3RT/M) = √(3kT/m); mean speed: v̄ = √(8RT/πM); most probable: v_p = √(2RT/M)Kinetic interpretation of temperature: ½mv²_rms = (3/2)kTEquipartition of energy: each degree of freedom has energy ½kT; monatomic f = 3, diatomic f = 5 (rigid), 7 (non-rigid)Specific heats: C_v = (f/2)R; C_p = C_v + R; γ = C_p/C_v = (f+2)/fMean free path λ = 1/(√2 πd²n); Avogadro's number N_A = 6.023 × 10²³

Ch 14

Oscillations

Covers simple harmonic motion (SHM) as a fundamental type of periodic motion. Students derive equations for displacement, velocity, and acceleration in SHM, and study simple pendulums, spring-mass systems, and energy in SHM. Damped, free, forced oscillations, and resonance are also covered.

Topics covered

SHM: x = A sin(ωt + φ); v = Aω cos(ωt + φ); a = −ω²x (restoring acceleration)Angular frequency ω = 2π/T = 2πf; ω = √(k/m) for spring-massSimple pendulum: T = 2π√(L/g); valid for small anglesSpring-mass system: T = 2π√(m/k); springs in parallel k_eff = k₁ + k₂; series 1/k_eff = 1/k₁ + 1/k₂Energy in SHM: KE = ½mω²(A²−x²); PE = ½mω²x²; total E = ½mω²A² = constantDamped oscillations: amplitude decays as A e^(−bt/2m)Resonance: maximum amplitude when driving frequency = natural frequency

Ch 15

Waves

Covers transverse and longitudinal waves, their properties, and the wave equation. Students study the superposition principle, stationary waves, normal modes in strings and pipes, and the Doppler effect. Newton's formula for speed of sound and Laplace's correction are important exam topics.

Topics covered

Wave equation: y = A sin(kx − ωt); wave speed v = ω/k = λ/T = fλSpeed of transverse wave in string: v = √(T/μ); where μ = linear mass densitySpeed of longitudinal wave (sound): v = √(B/ρ); Newton's formula v = √(P/ρ); Laplace correction: v = √(γP/ρ)Principle of superposition: y = y₁ + y₂Standing waves in string: nodes and antinodes; λₙ = 2L/n; fₙ = nv/2LBeats: beat frequency = |f₁ − f₂|; used for tuning instrumentsDoppler effect: f' = f(v ± v_o)/(v ∓ v_s); cases for approach and recession

Frequently Asked Questions

Can I revise Class 11 Physics in one day using summaries?

Yes. Each chapter summary here takes under 3 minutes to read. With 15 chapters, you can cover all of Class 11 Physics in a focused 2–3 hour session. Use these summaries to identify gaps — then revisit only those chapters in detail.

Are chapter summaries enough for CBSE Class 11 Physics board exam?

Summaries are for revision, not first learning. Use them after you've already studied the chapter — they quickly confirm what you remember and flag what you don't. For first-time study, read the NCERT textbook and work through important questions chapter-by-chapter.

What is covered in Class 11 Physics chapter summaries?

Each summary here covers the main concepts of the chapter, key topics that CBSE tests, and important points for the board exam. Deleted topics (removed from the 2025-26 CBSE syllabus) are clearly marked so you don't waste time on content that won't be tested.

What is the fastest way to revise Class 11 Physics for CBSE boards?

Read the chapter summary, then immediately close it and try to recall the key topics listed — without looking. Anything you miss, mark for one more read. This active recall method is proven to be 3× more effective than re-reading the textbook, and takes a fraction of the time.

Complete Study Pack — Class 11 Physics

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