Change log: page 3
New topics, content updates, published corrections, syllabus checks and new versions of the privacy policy and terms, newest first. Typo fixes are not listed: they do not change what a page teaches.
2092 changes Latest 8 Nov 2026
Page 3 of 11 · 200 changes on this page
November 2026
70 topics updated in Biology
Sexual Reproduction in Flowering Plants
Human Reproduction
The male reproductive system The female reproductive system Gametogenesis Menstrual cycle Fertilisation and implantation Pregnancy and embryonic development Parturition and lactation
Reproductive Health
Reproductive health: problems and strategies Population stabilisation and birth control Medical termination of pregnancy (MTP) Sexually transmitted infections (STIs) Infertility and assisted reproduction
Principles of Inheritance and Variation
Mendel’s experiments Inheritance of one gene Inheritance of two genes Polygenic inheritance Pleiotropy Sex determination Mutation Genetic disorders
Molecular Basis of Inheritance
DNA: structure and packaging Search for genetic material RNA world DNA replication Transcription Genetic code Translation Regulation of gene expression Human Genome Project DNA fingerprinting
Evolution
Origin of life Evolution of life forms Evidences for evolution Adaptive radiation Biological evolution Mechanism of evolution Hardy–Weinberg principle Modern synthetic theory A brief account of evolution Origin and evolution of man
Human Health and Disease
Health and disease Common diseases in humans Dengue and chikungunya Immunity HIV and AIDS Cancer Drug, alcohol and tobacco abuse
Microbes in Human Welfare
Microbes in household products Microbes in industrial products Microbes in sewage treatment Microbes in biogas production Microbes as biocontrol agents Microbes as biofertilisers
Biotechnology: Principles and Processes
Principles of biotechnology Tools of recombinant DNA technology Processes of recombinant DNA technology
Biotechnology and Its Applications
Biotechnology in agriculture Biotechnology in medicine Transgenic animals Ethical issues
Organisms and Populations
Ecosystem
Structure and function Productivity Decomposition Energy flow Ecological pyramids
Biodiversity and Conservation
- JEE Class 11 syllabus
- NEET Class 11 syllabus
- JEE Class 12 syllabus
- NEET Class 12 syllabus
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SI units
Clarified the 2019 SI definitions, the status of angle units, and the distinction between one mole of atoms and one mole of molecules.
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Significant figures
Specified the force direction in the work question and clarified guard digits, base-10 logarithms and approximate uncertainty propagation.
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Errors in measurement
Distinguished error, uncertainty, precision and resolution; corrected signed-deviation terminology, propagation assumptions and the rounded resistance uncertainty.
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Least count: vernier callipers and screw gauge
Clarified resolution versus uncertainty and repeatability, analogue interpolation, and the scale convention behind zero-error signs.
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Dimensions of physical quantities
Specified limiting static friction and the assumptions behind dimensional shortcuts, and distinguished dimensional equivalence from physical equality.
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Dimensional formulae and equations
Corrected the meaning of a dimensional equation and zero exponents, and stated the condition for using work = force × displacement.
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Dimensional analysis
Clarified the independence requirement when solving for exponents and the distinction between signed displacement and distance.
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Frame of reference and displacement
Clarified fixed versus moving origins, signed displacement versus distance, the inertial-frame condition, point-object modeling and graph intersections.
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Velocity and speed
Clarified differentiability, stationary points without reversal and the conditions under which endpoint averaging is guaranteed.
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Acceleration
Qualified the chain-rule shortcut, distinguished zero from non-zero constant acceleration, and corrected the explanation of mixed units.
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Equations of motion
Corrected the braking-distance inequality and uniqueness claims, clarified zero acceleration and endpoint averaging, and labelled the reaction-time assumption.
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Relative velocity
Specified reference frames and river assumptions, explained the equal-speed crossing limit, and distinguished relative speed from closing speed.
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Scalars and vectors
Clarified compatible physical quantities, current directions, impulse for varying force, vector equality at zero and fixed-origin changes.
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Multiplying a vector by a number
Corrected missing constant-velocity conditions and dimensional cancellation; clarified zero vectors, component ratios and the inertial-frame scope of F=ma.
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Adding vectors graphically
Specified rain and wind reference frames, handled zero-resultant directions, and corrected subtraction equality when the input vectors match.
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Resolution of vectors
Added the non-collinear resolution condition and handled zero vectors, normalisation, projection and vertical directions.
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Adding vectors by components
Specified boat/water/bank frames and handled degenerate sine rules, vertical resultants and the zero-vector orthogonality exception.
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Position, velocity and acceleration in a plane
Clarified fixed Cartesian axes, smooth paths and nonzero velocity, endpoint averaging and zero-velocity examples.
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Constant acceleration in a plane
Corrected net acceleration for a supported incline, included zero acceleration, and clarified initial positions and instantaneous tangent directions.
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Projectile motion
Corrected free fall, vertical projection and maximum-rise assumptions; clarified ceiling contact, drag comparisons and the perpendicular-velocity boundary.
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Uniform circular motion
Distinguished finite-interval velocity changes from instantaneous acceleration and unsigned angular speed from a signed angular derivative.
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Aristotle’s fallacy
Distinguished no net force from absent friction, included gravity in the thrown-ball explanation and stated the inertial-frame scope.
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Law of inertia
Clarified Newtonian translational inertia, inertial frames with non-rotating axes, and real forces on the braking-train ball.
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Newton’s first law
Added worked examples for instantaneous rest and accelerating frames; clarified non-rotating frames and the astronaut’s observer.
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Newton’s second law
Corrected changing-mass momentum balance and exact kgf/gf conversions; specified contact-impulse approximations and net forces in questions.
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Newton’s third law
Specified recoil and throwing reference frames; added worked examples for force partners and equal forces on unequal masses.
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Conservation of momentum
Corrected the straight-line restriction and collision energy explanation; clarified recoil frames, equal-velocity sticking and external-impulse assumptions.
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Equilibrium of a particle
Corrected uniform-tension assumptions and the steady-speed example; clarified equation sufficiency and symmetric string balance.
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Friction
Corrected static-friction generalisations, string tension and reduced normal force; qualified the empirical friction model and incline assumptions.
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Dynamics of circular motion
Scoped speed formulas to ideal skidding limits, corrected horizontal-string support and tangent-release explanations, and clarified formula domains.
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Solving problems in mechanics
Corrected string force-pair identification, separated static onset from kinetic motion, and qualified tension and pulley constraints.
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Scalar product
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Work-energy theorem
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Work
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Kinetic energy
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Work done by a variable force
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Work-energy theorem (variable force)
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Potential energy
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Conservation of mechanical energy
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Potential energy of a spring
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Power
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Collisions
Correct conceptual scope, physical assumptions and inconsistent answers; verify worked and practice calculations, curriculum coverage and mobile rendering. Scores provisional; independent approval pending.
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Rigid body motion
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Centre of mass
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Motion of the centre of mass
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Momentum of a system
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Vector product
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Angular velocity
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Torque and angular momentum
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Equilibrium of a rigid body
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Experiment: mass with a metre scale
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Moment of inertia
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Rotational kinematics
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Rotational dynamics
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Angular momentum about an axis
Correct rigid-body assumptions, signed quantities, momentum/energy scope and practice errors; verify arithmetic, sources, content and five screen widths. Provisional editorial scores; independent approval pending.
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Kepler’s laws
Manual content review; 82→94/100 provisional. Qualified fixed-Sun/negligible-planet model and the finite-mass two-body period law; AU is an exact length, not defined as the current Earth semi-major axis.
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Universal law of gravitation
Manual content review; 87→94/100 provisional. Restricted centre-distance formula to point masses or non-overlapping spherical mass distributions, including recap and practice.
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Gravitational constant
Manual content review; 84→94/100 provisional. Stated nearby-pair/perpendicular-force/small-angle torsion-balance approximations; reversal cancels a fixed offset rather than every error.
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Variation of g
Manual content review; 85→94/100 provisional. Separated spherical-symmetry exterior law from uniform-density interior law, and marked equal height/depth reductions as approximate.
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Gravitational potential energy
Manual content review; 88→94/100 provisional. Distinguished external work ΔU+ΔK from gravity work −ΔU; slow/no-net-kinetic-change assumption added where required.
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Escape speed
Manual content review; 76→94/100 provisional. Added isolated spherical non-rotating planet and negligible projectile/coasting assumptions; scoped zero-kinetic turning-point energy graph to radial motion.
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Earth satellites
Manual content review; 86→94/100 provisional. Added central-body approximation and circular-orbit scope; planet-weighing formula requires radius for circles or semi-major axis for ellipses and gives total two-body mass exactly.
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Energy of an orbiting satellite
Manual content review; 84→94/100 provisional. Corrected negative-potential-energy implication: escaping bodies also have U<0; binding depends on total energy and remaining bounded over time.
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Elasticity and plasticity
Manual content review 85→94/100 provisional. Separated NCERT stiffness terminology from recoverability; bounded rubber/chewing-gum examples by load and timescale.
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Stress and strain
Manual content review 84→94/100 provisional. Defined average engineering stress and static-equilibrium scope; identified original area, axial loading and negligible wire weight in examples.
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Hooke’s law
Manual content review 86→94/100 provisional. Corrected empirical-versus-microscopic-explanation false dichotomy and blanket claim that rubber never admits a linear approximation.
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Stress-strain curve
Manual content review 76→94/100 provisional. Corrected ultimate tensile load versus final fracture load throughout worked examples, formula sheet and FAQ; engineering area is original area.
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Elastic moduli
Manual content review 82→94/100 provisional. Made shear-angle equality approximate; clarified positive contraction versus signed lateral strain and isotropic linear-elastic Poisson bounds.
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Experiment: Young’s modulus of a wire
Manual content review 81→94/100 provisional. Referenced official NCERT Laboratory Manual Experiment9; distinguished preload from added mass and graph slope Δl/ΔM from l/M.
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Applications of elastic behaviour
Manual content review 78→94/100 provisional. Scoped rope factor10 to NCERT estimate and distinguished load-bearing metal area from stranded outer area.
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Pressure in fluids
Manual review 86→94/100 provisional. Distinguished exact standard atmosphere from variable sea-level pressure and uniform-density hydrostatic assumptions.
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Streamline and turbulent flow
Manual review 80→94/100 provisional. Corrected low-speed-only steadiness claim, arbitrary streamline-spacing interpretation and blanket transition at Re3000.
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Bernoulli’s principle
Manual review 83→94/100 provisional. Bounded speed-pressure comparison to the same Bernoulli constant, and specified negligible losses and no added/removed mechanical work.
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Viscosity
Manual review 78→94/100 provisional. Specified Newtonian constitutive model and fully developed no-slip laminar profiles; distinguished fluid inertia from turbulent onset.
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Experiment: viscosity from terminal velocity
Manual review 76→94/100 provisional. Verified procedure against NCERT lab Experiment13; corrected interval stopwatch readings, intercept fitting and alternative causes of unequal times.
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Surface tension
Manual review 79→94/100 provisional. Clarified reversible surface-creation work/free energy, total bubble inflation work and ideal Young contact-angle assumptions.
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Experiment: surface tension by capillary rise
Manual review 83→94/100 provisional. Verified NCERT lab Experiment12 including meniscus correction and two-reading height; corrected near-complete wetting versus any acute angle.
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Temperature and heat
Manual review 84→94/100 provisional. Distinguished net heat transfer from microscopic exchanges at equilibrium and scoped ideal drink/block examples.
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Measuring temperature
Manual review 78→94/100 provisional. Replaced universal two-fixed-point scale definition with elementary linear calibration and current Boltzmann-constant SI definition.
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Ideal-gas equation and absolute temperature
Manual review 85→94/100 provisional. Specified dilute classical regime and fixed-temperature/pressure constraints; identified additional mole-proportionality assumption.
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Thermal expansion
Manual review 82→94/100 provisional. Separated differential coefficient identities from finite-change approximations; bounded uniform free expansion, density and thermal-stress claims.
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Specific heat capacity
Manual review 86→94/100 provisional. Specified heating process, interval-average/constant heat capacity and equal absorbed-power comparison.
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Calorimetry
Manual review 88→94/100 provisional. Qualified isolated-system energy balance to exclude work, reactions and external exchange, while retaining published NCERT quotation.
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Experiment: specific heat by the method of mixtures
Manual review 79→93/100 provisional. Verified NCERT lab Experiment17; distinguished dry-chamber steam variant from NCERT water-bath procedure and included participating apparatus heat capacity.
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Change of state
Manual review 79→94/100 provisional. Restricted constant-temperature phase-change statements to pure-substance equilibrium at fixed pressure and clarified sublimation versus absence of liquid phase.
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Heat transfer
Manual review 78→93/100 provisional. Specified steady-conduction/contact assumptions and distinguished buoyancy circulation from surface-tension-driven flow.
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Newton’s law of cooling
Manual review 81→94/100 provisional. Specified constant-coefficient lumped-temperature model, participating capacity, no evaporation/phase change and model-dependent exactness.
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Thermal equilibrium
Manual review 80→94/100 provisional. Distinguished genuine equilibrium from maintained steady state and thermal balance from mechanical/chemical balance.
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Zeroth law of thermodynamics
Manual review 88→95/100 provisional. Clarified net versus microscopic heat transfer and stated thermometer disturbance/constant-capacity assumptions.
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Heat, internal energy and work
Manual review 81→94/100 provisional. Excluded organised bulk motion and clarified intramolecular vibrational potential energy, not just kinetic energy.
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First law of thermodynamics
Manual review 84→94/100 provisional. Specified closed-system, bulk-energy assumptions and transfers versus changes of stored quantities.
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Specific heat capacity of solids, water and gases
Manual review 78→93/100 provisional. Corrected classical solid heat capacity to per mole of atoms, with reference energy and high-temperature approximation.
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State variables and equation of state
Manual review 79→94/100 provisional. Corrected assertion that mass, energy and all state quantities cease to exist outside equilibrium; explained global versus local description.
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Thermodynamic processes
Manual review 73→93/100 provisional. Removed incorrect rule that sudden compression automatically permits PV^gamma; specified reversible constant-gamma assumptions and other work modes.
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Second law of thermodynamics
Manual review 82→94/100 provisional. Distinguished work-driven two-reservoir refrigerator model from heat-driven absorption systems with additional thermal exchanges.
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Reversible and irreversible processes
Manual review 78→94/100 provisional. Corrected sudden-compression shortcut and specified constant-gamma reversible adiabatic conditions.
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Carnot engine
Manual review 86→94/100 provisional. Bounded unique-four-step argument to simple construction without internal regeneration; distinguished universal efficiency theorem from unique mechanical cycle.
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Molecular nature of matter
Manual review 85→94/100 provisional. Qualified atomic/molecular scope to include ionic and network solids, thermal vibrations, isotopes and model-dependent forces.
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Behaviour of gases
Manual review 81→94/100 provisional. Corrected Dalton-law claim: an ideal reacting mixture still obeys the sum using its current composition.
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Kinetic theory of an ideal gas
Manual review 78→93/100 provisional. Corrected translational versus total internal energy, gas-rest-frame isotropy, wall-system momentum and statistical collision balance.
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Law of equipartition of energy
Manual review 77→94/100 provisional. Corrected contradictory vibrational mode count: one quadratic term receives half-kT, one fully excited harmonic vibration receives kT.
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Specific heat capacity from kinetic theory
Manual review 80→94/100 provisional. Specified fixed active classical mode count, vibrational excitation limits and classical solid heat capacity per mole of atoms.
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Mean free path
Manual review 79→93/100 provisional. Bounded formula to dilute identical hard spheres and separated equilibrium temperature scaling from individual speed-class collision statistics.
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Periodic and oscillatory motion
Manual review 82→94/100 provisional. Distinguished damped oscillation from exact periodicity and stable equilibrium from any zero-force point.
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Simple harmonic motion
Manual review 85→94/100 provisional. Corrected coordinate-origin classification: sin²(ωt) is SHM about its shifted equilibrium, independent of the chosen coordinate origin.
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SHM and uniform circular motion
Manual review 90→94/100 provisional. Distinguished actual circular trajectory from perpendicular projection and qualified parallel illumination versus perspective distortion.
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Velocity and acceleration in SHM
Manual review 87→94/100 provisional. Distinguished acceleration magnitude from signed acceleration, zero acceleration from a directed vector, and pendulum tangential from radial acceleration.
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Force law for SHM
Manual review 84→94/100 provisional. Specified one-dimensional constant-mass positive-stiffness net-force model and differential-equation solution.
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Energy in SHM
Manual review 88→94/100 provisional. Specified undriven time-independent conservative model and equilibrium potential-energy reference.
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The simple pendulum
Manual review 81→93/100 provisional. Specified point-bob centre-to-pivot length, uniform gravitational field and precision-dependent small-angle limit.
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Experiment: simple pendulum and loss of energy
Manual review 76→94/100 provisional. Read and incorporated NCERT Laboratory Manual Experiment6 and Activity7, same-direction timing, hook/length offset and amplitude sampling.
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Wave motion
Manual review 79→93/100 provisional. Qualified energy-without-matter statement to first-order mechanical waves; corrected cork motion, real Stokes drift and train analogy.
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Transverse and longitudinal waves
Manual review 82→94/100 provisional. Specified sinusoidal driver and static shear modulus rather than claiming fluids never resist shear.
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Displacement relation for a progressive wave
Manual review 87→94/100 provisional. Specified positive k and omega and equilibrium material-coordinate meaning for longitudinal displacement.
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Speed of a travelling wave
Manual review 80→93/100 provisional. Distinguished phase/group speeds and nondispersive, small-slope, constant-tension limits.
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Principle of superposition of waves
Manual review 84→94/100 provisional. Restricted principle to linear equations/boundaries and vector components, corrected nonnegative amplitude and full phase solutions.
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Reflection of waves and standing waves
Manual review 86→94/100 provisional. Specified displacement versus pressure reflection sign, matched-interface exceptions and normal-mode versus arbitrary driving frequency.
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Experiment: speed of sound with a resonance tube
Manual review 76→94/100 provisional. Incorporated NCERT Laboratory Manual Experiment16, repeated bidirectional observations, fork orientation, same-frequency resonance versus overtone and common-correction assumptions.
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Beats
Manual review 76→94/100 provisional. Corrected absolute beat frequency, envelope magnitude, ordinary inaudibility of illustrative9/11Hz waves and approximate perceived pitch.
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Electric charge
OpenAI Codex review: read full lesson, FAQs and practice; independently checked equations, numerical answers, signs and physical assumptions. Corrected misleading or missing qualifications; saved only as unpublished draft.
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Conductors and insulators
OpenAI Codex review: read full lesson, FAQs and practice; independently checked equations, numerical answers, signs and physical assumptions. Corrected misleading or missing qualifications; saved only as unpublished draft.
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Basic properties of electric charge
OpenAI Codex review: read full lesson, FAQs and practice; independently checked equations, numerical answers, signs and physical assumptions. Corrected misleading or missing qualifications; saved only as unpublished draft.
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Coulomb’s law
OpenAI Codex review: read full lesson, FAQs and practice; independently checked equations, numerical answers, signs and physical assumptions. Corrected misleading or missing qualifications; saved only as unpublished draft.
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Forces between multiple charges
OpenAI Codex review: read full lesson, FAQs and practice; independently checked equations, numerical answers, signs and physical assumptions. Corrected misleading or missing qualifications; saved only as unpublished draft.
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Electric field
OpenAI Codex review: read full lesson, FAQs and practice; independently checked equations, numerical answers, signs and physical assumptions. Corrected misleading or missing qualifications; saved only as unpublished draft.
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Electric field lines
OpenAI Codex review: read full lesson, FAQs and practice; independently checked equations, numerical answers, signs and physical assumptions. Corrected misleading or missing qualifications; saved only as unpublished draft.