Change log: page 4
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 7 Nov 2026
Page 4 of 11 · 200 changes on this page
November 2026
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Electric flux
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 Corrected misleading or missing qualifications; saved only as unpublished draft.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 dipole
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 Corrected misleading or missing qualifications; saved only as unpublished draft.
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Dipole in a uniform 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 Corrected misleading or missing qualifications; saved only as unpublished draft.
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Continuous charge distribution
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 Corrected misleading or missing qualifications; saved only as unpublished draft.
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Gauss’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 Corrected misleading or missing qualifications; saved only as unpublished draft.
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Applications of Gauss’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 Corrected misleading or missing qualifications; saved only as unpublished draft.
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Electrostatic potential energy
OpenAI Codex full content review: Main infinity-zero discussion omitted finite-work condition already explained in FAQ; promoted it to the lesson. Mechanical energy conservation now states only conservative forces do work.
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Electrostatic potential
OpenAI Codex full content review: Example4 incorrectly used K=qΔV for kinetic gain; corrected ΔK=−qΔV. Practice proton loss had a positive qΔV despite ΔV=−200V; corrected ΔU and gain separately.
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Potential due to a point charge
OpenAI Codex full content review: V=Er labelled magnitudes was ambiguous for negative sources; now |V|=|E|r and signed radial component Er explicit.
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Potential due to a dipole
OpenAI Codex full content review: FAQ exact axial kp/(r²−a²) lacked positive-side exterior r>a condition. Far-field summaries and derivative FAQ now state their scope; point dipole excludes origin.
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Potential due to a system of charges
OpenAI Codex full content review: Standalone shell questions omitted uniform spherical charge distribution; made explicit. Kinetic-energy sign example now states only electric force acts.
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Equipotential surfaces
OpenAI Codex full content review: Field direction needs nonzero E and a smooth surface; an equipotential gives a normal axis, while neighbouring potentials determine sense.
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Potential energy of a system of charges
OpenAI Codex full content review: All examples, pair counting, square energies and FAQ answers correct; added explicit quasistatic assembly and exclusion of divergent point-charge self-energy.
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Potential energy in an external field
OpenAI Codex full content review: Infinity reference cannot be used for an ideal uniform field; finite-reference option added. Dipole energy now explicitly assumes fixed permanent rigid moment.
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Electrostatics of conductors
OpenAI Codex full content review: Electrons do not literally stop microscopic motion: revised to zero net drift. Surface boundary field now signed vector in vacuum; off-centre sphere uniform exterior needs isolation/no external field.
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Dielectrics and polarisation
OpenAI Codex full content review: P=ε₀χE now defines total interior E. Field reduction limited to fixed source charge/wide-slab model; fixed voltage battery case distinguished.
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Capacitors and capacitance
OpenAI Codex full content review: Faraday FAQ confused amount of charge in C with Faraday constant in C/mol; corrected and linked exact SI definitions.
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The parallel plate capacitor
OpenAI Codex full content review: Outside zero field restricted to ideal infinite-sheet model; plate gap must be small relative to each lateral dimension.
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Effect of a dielectric on capacitance
OpenAI Codex full content review: Bound charges cancel field rather than remove free plate charge. General KC0 requires homogeneous linear medium filling entire field region.
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Combination of capacitors
OpenAI Codex full content review: Series proof wrongly inferred zero net capacitor/junction charge from zero wire field; replaced with conserved charge of isolated initially neutral junction and counterexample for charged junction.
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Energy stored in a capacitor
OpenAI Codex full content review: Clarified reversible stored charging work versus extra circuit dissipation; formula assumes constant linear capacitance.
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Electric current
OpenAI Codex full review: Clarified signed forward-minus-backward charge amounts, conventional-current arrow and uniform-area restriction; distinguished SI adoption from effective date and orbital time-averaged magnitude.
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Electric currents in conductors
OpenAI Codex full review: Corrected bound-electron polarisation, metallic-solid scope, equilibrium zero net drift, charge screening versus removal and negative mobile charge; clarified metallic band alternatives.
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Ohm’s law
OpenAI Codex full review: Added fixed physical conditions, uniform isotropic conductor and nonzero-current ratio; stretching now assumes unchanged resistivity; quick answer no longer calls resistivity material-only.
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Experiment: resistance using Ohm’s law
OpenAI Codex full review: Corrected ammeter wire-plus-voltmeter loading; added low-voltage lab supply and maximum rheostat setting before closure; reading uncertainties explicitly assigned and first-order maximum estimate distinguished.
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Drift of electrons
OpenAI Codex full review: Corrected individual-electron speed claim and false every-electron-in-slab crossing claim; derived net transport, steady-state scope and mean transport timescale. Accurate page alt/caption supersede misleading old asset title.
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Limitations of Ohm’s law
OpenAI Codex full review: Added negative differential versus static resistance distinction, nonzero-current ratio and operating-range restrictions for GaAs and Ohm’s law.
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Resistivity of various materials
OpenAI Codex full review: Illustrative NCERT ranges no longer imply unique semiconductor identification; intrinsic regime qualified; replaced unverifiable NASA resistivity attribution with grade-specific Kanthal1.09e−6Ωm and removed dated price ratio.
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Temperature dependence of resistivity
OpenAI Codex full review: Corrected reference-temperature coefficient criterion with exact converted coefficient; distinguished classical speed explanation from lattice scattering and intrinsic regime; clarified849°C vs NCERT847°C intermediate rounding.
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Electrical energy and power
OpenAI Codex full review: Scoped IV heat to resistors, receiving-end transmission voltage and AC transformers; bulb comparison qualified; fuse time-current behaviour and limits of classroom10A estimate corrected with Eaton primary source.
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Combination of resistors
OpenAI Codex full review: Added positive finite resistor/ideal wire/series junction assumptions and strict-inequality scope; power-rating sum depends on cooling; open failure distinguished from shared fault protection.
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Cells, emf and internal resistance
OpenAI Codex full review: Corrected galvanic versus electrolytic source terminology and terminal voltage existence in open circuit; included idealr0 exception, internal work direction and constant-source finite-positive-r model.
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Cells in series and in parallel
OpenAI Codex full review: Corrected continuous optimum versus discrete allowed integer groupings and fixed-current versus fixed-load internal heat claim; charging-direction current does not imply primary-cell rechargeability.
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Kirchhoff’s rules
OpenAI Codex full review: Required independent loops, negligible node charge storage and lumped quasistatic scope; all induced emfs including external flux must be included. Independently solved cube terminal classes and NCERT networks.
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Wheatstone bridge
OpenAI Codex full review: Added functioning detector and energised-source conditions for null test; sensitivity depends on source/detector/arm resistances; unbalanced bridge needs more than series-parallel reductions alone.
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Metre bridge
OpenAI Codex full review: Corrected absolute midpoint/end-error cancellation claims, first-order unequal-end cancellation and uncertainty interpretation;6.2% example explicit; added opposite-end deflection check and diameter measurement precautions.
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Magnetic force
OpenAI Codex full review: Corrected signed charge versus force magnitude |q| in principal formula, summary and metadata; Fleming rule now applies only to magnetic part. Added same-frame and uniform external-field scope.
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Motion in a magnetic field
OpenAI Codex full review: Added missing nonrelativistic assumptions to frequency/period claims, corrected at-any-speed parallel-E FAQ and clarified q as magnitude, signed axial displacement versus pitch length, and antiparallel straight-line case.
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Biot–Savart law
OpenAI Codex full review: Added steady-current/vacuum/r>0 and finite-element approximation conditions; finite-wire endpoint angles require signs outside segment. Moving-charge approximation excludes radiation terms; μ0 now approximate consistently and SI effective date explicit.
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Field on the axis of a loop
OpenAI Codex full review: Corrected centre weakest in entire plane to disk interior; divergence belongs only to ideal filament. Added thin-flat N-turn, fixed-current rewinding and arc-lead assumptions; far-axis coordinate is distance.
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Ampere’s circuital law
OpenAI Codex full review: Corrected zero-integral inference: constant magnitude alone does not imply B=0, tangential signed component is required. Added orientation in BL reduction, ideal filament limitation and hollow-pipe cavity distinction.
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The solenoid
OpenAI Codex full review: Restricted uniform/radius-independent field to ideal infinite winding or central region of long finite air-core solenoid; clarified discrete winding, return lead, saturation and toroid leakage approximations.
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Force between parallel currents
OpenAI Codex full review: Corrected unconditional repulsive levitation stability: vertical stability requires constraint and fixed current, lateral displacement is unstable. Replaced pressure handwave, qualified symmetric perpendicular segments and infinite-wire divergent torque.
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Torque on a current loop
OpenAI Codex full review: Alignment needs damping to settle; fixed-current/fixed-moment and flexible-loop assumptions explicit. Dipole equivalence restricted to far field. Existing NCERT energy-sign correction retained; original forward motion cannot determine angular speed.
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Moving coil galvanometer
OpenAI Codex full review: Corrected uniform radial field to nearly constant magnitude at active sides, slow-AC exception and same-movement resistance comparison. Added conversion domains, fixed geometry for N scaling and model-only loading example.
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Experiment: galvanometer resistance
OpenAI Codex full review: Added valid resistance ranges, zero-corrected linear scale and source resistance correction. Distinguished figure-of-merit k from torsion constant; graph fitting does not eliminate systematic error and extrapolated intercept can be uncertain.
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The bar magnet
OpenAI Codex full review: Corrected false claim that zero net magnetic moment rules out local poles/fields; distinguished an infinite wire from a finite zero-moment source.
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Gauss’s law for magnetism
OpenAI Codex full review: Corrected universal closed-loop claim: divergence-free lines have no local endpoints but need not all close. Exact flux uses surface integral with outward normals; matching open surfaces require consistent orientation.
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Magnetisation and magnetic intensity
OpenAI Codex full review: Corrected general H=external-only claim throughout body, FAQs, summary and quick answer: finite samples have demagnetising fields; H=nI and Bm=μ0M require ideal uniformly filled long solenoid.
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Magnetic properties of materials
OpenAI Codex full review: Corrected induced-moment energy from −m·B to effective −½αB² for m=αB, checked by integration and primary research.
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Experiments of Faraday and Henry
OpenAI Codex full review: Qualified current-duration and pointer-reset claims with resistive approximation and finite transients; motion must change linked flux.
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Magnetic flux
OpenAI Codex full review: Replaced literal field-line count and finite-sum equality with visual analogy and exact surface integral; signed projected area and normal conventions explicit.
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Faraday’s law of induction
OpenAI Codex full review: Added missing resistive approximation to I=ε/R and current-following-emf claims; inductive energy can sustain lagging current.
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Lenz’s law
OpenAI Codex full review: Corrected FAQ claiming current can oppose emf only with cell/capacitor: inductive stored energy is another cause; Lenz law fixes polarity rather than arbitrary existing current.
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Motional emf
OpenAI Codex full review: Corrected magnetic force doing work qvBl: motional line integral supplies emf, total magnetic force does no net work on each charge, external mechanical work supplies electrical energy.
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Eddy currents
OpenAI Codex full review: Corrected only-metals and all-energy-always-heat claims; distinguished passive braking from mechanical transfer and transient field storage.
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Inductance
OpenAI Codex full review: Corrected universal constant/current-independent L claim for nonlinear ferromagnetic cores; fixed geometry, linear reciprocal medium and saturation/hysteresis scope explicit.
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AC generator
OpenAI Codex full review: Specified ideal rotating-coil geometry, constant speed, initial normal and phase; output current requires a connected load and can be phase shifted.
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AC voltage applied to a resistor
OpenAI Codex full review: Qualified sinusoidal constant-R operating-temperature model; corrected half-cycle sign and specified triangle/sawtooth ranges.
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Phasors
OpenAI Codex full review: Corrected LC-combination always-out-of-phase assertion, and whole-diagram rotation claim: relative phases preserved but fixed-time instantaneous values change.
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AC voltage applied to an inductor
OpenAI Codex full review: Corrected false claim symmetric source forces zero integration constant: ideal L can retain initial dc current. Every phase/example result now explicitly scoped to zero-offset sinusoidal solution.
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AC voltage applied to a capacitor
OpenAI Codex full review: Corrected absolute no-DC-lamp-glow claim with possible charging flash and no sustained current; AC glow requires sufficient current.
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Series LCR circuit
OpenAI Codex full review: Specified sinusoidal steady state, positive constant R and fixed source amplitude for resonance peak; undamped R=0 forced resonance has no finite sinusoidal steady state.
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Power in ac circuits
OpenAI Codex full review: Fixed reactive-power sign inconsistency with NCERT current-phase convention; wattless components stated as magnitudes, signed conventional Q=−VI sinφ.
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Transformers
OpenAI Codex full review: Corrected primary back-emf sign and ideal-transformer assumptions: negligible winding drops/magnetising current, not universally small load currents.
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Displacement current
OpenAI Codex full review: Qualified vacuum-gap, negligible-fringing/quasistatic and axial-symmetry assumptions; distinguished full-area displacement current from smaller-loop fraction.
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Electromagnetic waves
OpenAI Codex full review: Restricted perpendicular/in-phase E/B=c and equal energy shares to freely travelling plane vacuum wave, rather than near fields, standing superpositions or arbitrary media.
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Electromagnetic spectrum
OpenAI Codex full review: Replaced unsupported Wikipedia sources for Gunn devices, microwave heating, ozone height, glass UV transmission and gamma energy with primary NASA/NOAA/FDA/CNSC/research evidence.
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Spherical mirrors
OpenAI Codex full review: Qualified paraxial/small-aperture mirror formulas, real versus virtual object signs, convex-image claims and finite versus infinite images. Half-aperture completeness and brightness now state field/illumination assumptions. Recomputed all worked images, jogger average/inst
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Refraction
OpenAI Codex full review: Resolved NCERT Fig9.27 printed47°/answer-key41° mismatch: literal result33.7° first, alternative38.2° explicitly separate. Visually checked current PDF printed249. Added phase-speed, isotropic stationary-interface, fixed-frequency and near-normal apparent-depth assumptions
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Experiment: glass slab
OpenAI Codex full review: Corrected liquid-method wording: translate whole microscope with focus unchanged; clarified constant-offset cancellation and conditional thickness advantage. Uncertainties are conservative first-order bounds with assumed per-reading error; shared top-surface reading is cor
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Total internal reflection
OpenAI Codex full review: Qualified ideal lossless TIR: evanescent field exists but no average transmitted normal power; fibres still have attenuation/bending losses. Acceptance calculation now states air, straight step-index and meridional rays; includes axial ray, excludes exactly grazing entry,
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Lenses
OpenAI Codex full review: Added thin/paraxial equal-surrounding-medium and index contrast assumptions; convex/concave power and image rules no longer universal. Corrected dimensionally incomplete power explanation to deflection per ray height; single-surface example now specifies curvature orientat
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Experiment: focal lengths
OpenAI Codex full review: Clarified positive-distance magnitudes, thin/paraxial model and worst-case first-order uncertainty. Six reversed pairs give12 plotted points, not12 independent observations; parallax is a convenient method rather than the only method. Qualified convex-mirror image claims a
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Prism
OpenAI Codex full review: Specified same external medium, higher prism index, principal-plane ray and emergence range; fixed universal two-incidences and both-bends claims. Critical incidence means threshold grazing emergence, with TIR strictly beyond it; symmetric path is parallel to base only for
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Experiment: prism i–δ graph
OpenAI Codex full review: Corrected hollow-prism wall explanation: glass index cancels between parallel interfaces but air-to-liquid net angular refraction remains. Illustrative samples, material-dependent angle range and monochromatic comparisons made explicit; graph fitting follows trend rather t
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Optical instruments
OpenAI Codex full review: Separated signed/magnitude magnification, conventional near point, optical tube length and lens separation; near-point L-based compound formula now approximate. Removed obsolete fundamental9×/1cm limits, specified Keplerian versus Galilean telescope and historical observer
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Huygens principle
OpenAI Codex full review: Qualified isotropic phase-speed/ray-normal and no-absorption assumptions; coherent ideal line source replaces generic glowing filament as cylindrical-wave source. Clarified outgoing-wave/backwave construction versus real reflection and the approximate, geometry-specific ob
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Refraction and reflection by Huygens principle
OpenAI Codex full review: Corrected energy-is-only-amplitude explanation: photon energy unchanged at a stationary transparent boundary, but intensity also depends on medium properties and reflected power. Distinguished phase optical path from dispersive pulse transit time; Fermat means stationary o
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Coherent and incoherent addition
OpenAI Codex full review: Added matching polarisation, local intensity, initial phase and finite observation-time assumptions; coherent orthogonal polarisation has zero ordinary intensity cross term. Fixed amplitude sign, false spatially uniform incoherent illumination and overly broad only-one-sou
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Young’s double-slit experiment
OpenAI Codex full review: Specified symmetric initial phase, coherence, polarisation, small-angle and finite-slit-envelope conditions; adjacent bright-dark separation is half fringe width. Missing-geometry NCERT10.6 now gives general D/d answers before labelled assumed numerical values; finite-scre
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Diffraction
OpenAI Codex full review: Corrected two-slit intensity construction to product of diffraction envelope and interference factor, not added intensity patterns. Specified scalar uniform Fraunhofer/small-angle scope and no-first-minimum case a<λ; exact sine minima added to formula sheet. Independently
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Polarisation
OpenAI Codex full review: Separated ideal polariser transmission from real losses/leakage; circular/elliptical polarisation is not random unpolarised light, and a rotating analyser alone cannot distinguish circular from unpolarised. Display test now requires known linear LCD output, with an inconcl
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Brewster’s law
OpenAI Codex full review: Specified lossless isotropic non-magnetic different-index interface, relative index and initially unpolarised input; p-only incidence has zero reflected beam, index-matched interface no reflection. Removed universal most-s-power-transmitted claim (diamond counterexample co
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Electron emission
OpenAI Codex full content review: corrected physical assumptions, explanatory precision and source/metadata consistency; independently recalculated examples. Unpublished review draft.
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Photoelectric effect
OpenAI Codex full content review: corrected physical assumptions, explanatory precision and source/metadata consistency; independently recalculated examples. Unpublished review draft.
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Experimental study of the photoelectric effect
OpenAI Codex full content review: corrected physical assumptions, explanatory precision and source/metadata consistency; independently recalculated examples. Unpublished review draft.
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Photoelectric effect and the wave theory
OpenAI Codex full content review: corrected physical assumptions, explanatory precision and source/metadata consistency; independently recalculated examples. Unpublished review draft.
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Einstein’s photoelectric equation
OpenAI Codex full content review: corrected physical assumptions, explanatory precision and source/metadata consistency; independently recalculated examples. Unpublished review draft.
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Photon
OpenAI Codex full content review: corrected physical assumptions, explanatory precision and source/metadata consistency; independently recalculated examples. Unpublished review draft.
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Wave nature of matter
OpenAI Codex full content review: corrected physical assumptions, explanatory precision and source/metadata consistency; independently recalculated examples. Unpublished review draft.
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Rutherford’s nuclear model
OpenAI Codex full content review: corrected model domains, spectroscopy and quantum-state explanations; independently recomputed numerical examples and checked primary sources. Unpublished review draft.
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Atomic spectra
OpenAI Codex full content review: corrected model domains, spectroscopy and quantum-state explanations; independently recomputed numerical examples and checked primary sources. Unpublished review draft.
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Bohr model
OpenAI Codex full content review: corrected model domains, spectroscopy and quantum-state explanations; independently recomputed numerical examples and checked primary sources. Unpublished review draft.
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Line spectra of hydrogen
OpenAI Codex full content review: corrected model domains, spectroscopy and quantum-state explanations; independently recomputed numerical examples and checked primary sources. Unpublished review draft.
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De Broglie and Bohr’s postulate
OpenAI Codex full content review: corrected model domains, spectroscopy and quantum-state explanations; independently recomputed numerical examples and checked primary sources. Unpublished review draft.
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Composition of the nucleus
OpenAI Codex full content review: corrected nuclear/atomic model boundaries, decay and fusion explanations, historical and current source claims; independently checked all numerical examples. Unpublished review draft.
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Size of the nucleus
OpenAI Codex full content review: corrected nuclear/atomic model boundaries, decay and fusion explanations, historical and current source claims; independently checked all numerical examples. Unpublished review draft.
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Binding energy
OpenAI Codex full content review: corrected nuclear/atomic model boundaries, decay and fusion explanations, historical and current source claims; independently checked all numerical examples. Unpublished review draft.
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Nuclear force
OpenAI Codex full content review: corrected nuclear/atomic model boundaries, decay and fusion explanations, historical and current source claims; independently checked all numerical examples. Unpublished review draft.
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Radioactivity
OpenAI Codex full content review: corrected nuclear/atomic model boundaries, decay and fusion explanations, historical and current source claims; independently checked all numerical examples. Unpublished review draft.
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Nuclear energy
OpenAI Codex full content review: corrected nuclear/atomic model boundaries, decay and fusion explanations, historical and current source claims; independently checked all numerical examples. Unpublished review draft.
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Metals, insulators and semiconductors
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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Intrinsic semiconductor
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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Extrinsic semiconductor
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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p-n junction
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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Semiconductor diode
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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Junction diode as a rectifier
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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Zener diode
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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LED, photodiode and solar cell
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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Experiment: identifying components
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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Logic gates
OpenAI Codex read the published lesson, FAQs and practice, corrected conceptual limits and verified worked answers independently. Content and five-width layout checks accompany this unpublished revision. Simulations excluded.
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Importance of chemistry
Clarify matter, branches of chemistry and disinfection; correct sample precision in cisplatin example.
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Nature of matter
Correct states-of-matter generalisations, brass classification and plasma definition; distinguish molecular compounds from ionic lattices.
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Properties of matter
Correct pressure significant figures and SI definition; clarify density and temperature statements.
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Uncertainty in measurement
Correct uncertainty interpretation, significant-figure assumptions and engineering notation; explain procedure-specific uncertainty.
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Laws of chemical combination
Clarify Avogadro particles and gas conditions, composition evidence and mass-measurement precision.
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Dalton’s atomic theory
Correct isobar mass-number error, preserve molecular formulas in particle counting and qualify modern limits of Dalton’s postulates.
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Atomic and molecular masses
Distinguish isotope mass from average atomic mass and clarify atomic-weight terminology and rounded constants.
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Mole concept
Correct molar-mass units and post-2019 approximation; clarify mass units, particle counts and significant figures.
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Percentage composition
Correct oxygen-by-difference assumptions, empirical-ratio rounding, purity inference and formula-unit distinction.
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Stoichiometry
Correct steam volume, solution mixing and limiting-reactant assumptions; remove unsupported ethanol molarity estimate and fix precision.
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Sub-atomic particles
Clarify charge signs and excess-electron counts, include buoyancy qualification and exact elementary charge, and refine subatomic FAQ.
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Atomic models
Correct bromine isotope reasoning, isotope-effect claims and penetration generalisations; clarify particle counts and precision.
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Developments leading to Bohr’s model
Correct cosmic-ray classification and photoelectric assumptions; clarify optical power and quantitative precision.
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Bohr’s model
Clarify Balmer UV limit, ensemble line counts and direct-transition assumptions; fix photon-energy sign and He+ radius precision.
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Towards the quantum mechanical model
Correct uncertainty lower-bound interpretation and non-relativistic assumptions; clarify thermal wavelength and probability distributions.
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Quantum mechanical model
Correct spectral-model limits, spin projection, probability density and exchange description; qualify filling-order and magnetic assumptions.
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Why classify elements?
Qualify family predictions, reactivity and configuration rules; repair biological analogy and synthetic-element wording.
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Genesis of periodic classification
Clarify hydrogen placement; verify historical predictions and existing germanium melting-point correction.
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Modern periodic law
Correct nuclear-charge units, periodicity meaning, completed period7 and old group-label mapping; clarify Pd and isotope exceptions.
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Naming elements above 100
Correct naming-stage and approval explanation; distinguish honorees, former names and predicted superheavy configurations.
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Configurations and the periodic table
Align quick answer and FAQs with Pd and transition-metal exceptions; qualify orbital energies and valence-electron definition.
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s, p, d and f blocks
Correct block exceptions, group16/electron-gain claims and Gd group assignment; remove invented metallic-trend weighting.
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Periodic trends
Correct hypervalent bonding, formal oxidation state and noble-gas claims; resolve ambiguous practice and qualify periodic trends.
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Kössel–Lewis approach
Distinguish formal from physical charges, clarify valence/duplet rules and isolated structures, and scope expanded-octet models.
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Ionic bond
Clarify full stability balance, conductivity scope and thermodynamic conventions while retaining verified Born–Haber examples.
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Bond parameters
Correct CO2 resonance reasoning and bond-angle definition; qualify bond-order trends, charge averages and dipole-based ionic estimates.
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VSEPR theory
Correct ClF3 repulsion comparison and domain counting; qualify shortcuts, hybridisation labels and shape arguments.
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Valence bond theory
Clarify elementary VB limits, phase conventions and rotational barriers; distinguish schematic H2 enthalpy from exact well depth.
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Hybridisation
Treat hybridisation as a model, correct lone-pair charge counting and CO2 pi description, and qualify hypervalent d labels.
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Molecular orbital theory
Correct dimer nonexistence and stability claims, nuclear repulsion and MO probability interpretation; qualify LCAO approximations.
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Homonuclear diatomic molecules
Correct categorical dimer nonexistence and equal-order stability ranking; distinguish C2+ model occupancy from actual quartet ground state.
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Hydrogen bonding
Correct hydrogen-bond scope and strength generalisations, bare-proton imagery and chloride example; qualify intramolecular and dimer effects.
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Metallic bonding
Clarify core electrons, conduction and cohesion comparisons; remove electron-count-only inference and refine mercury explanation.
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Thermodynamic terms
Clarify internal energy, system boundaries and reference zeros; qualify ideal isolation and fix the living-cell example.
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Work, enthalpy and heat capacity
Correct free/adiabatic expansion and constant-volume conditions; state heat/work assumptions and make the piston endpoint physically consistent.
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Calorimetry
Clarify calorimeter boundaries, work and heat-loss corrections; improve numerical precision and food-energy explanation.
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Reaction enthalpy and Hess’s law
Clarify molar reaction quantities, standard states and formation zeros; refine thermochemical coefficients, sample units and temperature assumptions.
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Combustion, bond and lattice enthalpies
Distinguish mean from sequential bond enthalpies, qualify solution/lattice criteria and thermal corrections, and clarify Hess endpoints.
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Enthalpy of neutralization
Qualify neutralisation heat, use stoichiometric equivalents, and improve calibration, mixing-temperature and heat-loss interpretation.
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Experiment: enthalpy of solution of copper sulphate
Match calibration fill and initial temperatures; correct Hess-cycle concentration assumptions and dissolution interpretation.
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Spontaneity, entropy and Gibbs energy
Correct zero-K motion and useful-work sign; distinguish actual from standard Gibbs driving force and fix entropy/stability conditions.
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Gibbs energy and equilibrium
Correct enthalpy-only equilibrium inference, reversibility and temperature extrapolation; clarify activities and1atm versus1bar reference.
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Equilibrium in physical processes
OpenAI Codex review: Clarified phase coexistence, reservoir equilibrium, Henry-law species and volatility limits; refined examples and revision metadata.
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Dynamic equilibrium in chemical processes
OpenAI Codex review: Corrected fixed-volume thermodynamic criterion, isotope-exchange inference and phase-exhaustion limits; qualified rate analogies.
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Law of chemical equilibrium and equilibrium constant
OpenAI Codex review: Distinguished activity and concentration constants, exercise datasets and significant figures; aligned reaction-manipulation assumptions.
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Homogeneous equilibria
OpenAI Codex review: Corrected dimensional Kp/Kc comparisons, units and standard-state conversion; specified ideal-gas and dissociation assumptions.
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Heterogeneous equilibria
OpenAI Codex review: Corrected phase-exhausted equilibrium, pure-phase activities and silver-oxide net ionic expression; labelled stipulated CaCO3 data.
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Applications of equilibrium constants
OpenAI Codex review: Replaced universal conversion thresholds with mass-balance reasoning; corrected Q misconception, ICE constraints and practice example.
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Equilibrium constant, reaction quotient and Gibbs energy
OpenAI Codex review: Clarified reaction Gibbs slope, dimensionless activities, zero-Q limits and biochemical coupling conventions.
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Factors affecting equilibria
OpenAI Codex review: Specified perturbation constraints, Kp/Kc temperature distinction and catalyst limits; corrected ammonia-removal wording and examples.
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Ionic equilibrium in solution
OpenAI Codex review: Corrected weak-electrolyte percentage definition, water background ions, dissociation terminology and continuum-solvation assumptions.
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Acids, bases and salts
OpenAI Codex review: Clarified Arrhenius scope, proton-pair donation, ammonia amphiprotism and BeCl2 structure; improved acid/base practice explanations.
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Ionization of acids and bases
OpenAI Codex review: Corrected ascorbic constant, ammonium hydrolysis and pH/activity assumptions; qualified polyprotic and hydrolysis approximations.
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Experiment: acid-base titration with an indicator
OpenAI Codex review: Corrected titrant placement, endpoint/equivalence distinction, indicator wording, dilution preparation and measurement precision.
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Buffer solutions
OpenAI Codex review: Distinguished exact activity identity from prepared-concentration approximation; corrected buffer capacity and dilution claims.
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Solubility equilibria of sparingly soluble salts
OpenAI Codex review: Corrected supersaturation, free-ion versus total solubility, Fe hydrolysis and reference-constant issues; qualified model calculations.
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Classical idea of oxidation and reduction
Correct Hg relative-composition and H2S oxidation reasoning; clarify classical-rule limits, combustion, corrosion and photosynthesis.
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Redox reactions as electron transfer
Clarify electron transfer, half-reaction states and product scope; qualify displacement predictions and deposition mass assumptions.
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Oxidation number
Correct redox classification rules, oxidation-state exceptions and formal assignments; update IUPAC terminology and chemical fluorine synthesis claim.
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Redox reactions and electrode processes
Distinguish standard from actual cell driving force, correct activity-based standard conditions and clarify electrode, salt-bridge and displacement behaviour.
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General introduction to organic chemistry
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Tetravalence of carbon and shapes
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Structural representations
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Classification of organic compounds
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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IUPAC nomenclature of organic compounds
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Isomerism
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Organic reaction mechanism
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Purification of organic compounds
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Qualitative analysis of organic compounds
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Quantitative analysis
OpenAI Codex read the full lesson, FAQs and practice, verified source-specific claims, corrected chemistry and naming overclaims, and independently recomputed formulas, isomer counts and analytical answers. New unpublished draft; simulations unchanged.
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Types of solutions
OpenAI Codex review: Corrected alloy/phase classification, fluoride threshold and IV-fluid overclaims, colloid size boundaries and original-state labels.
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Concentration of solutions
OpenAI Codex review: Clarified temperature invariance conditions, ppm reporting bases, analytical electrolyte composition and appropriate rounding.
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Solubility
OpenAI Codex review: Corrected universal gas-solubility claims, Henry-law conditions and methane source; refined saturation, diving and oxygen examples.
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Vapour pressure of solutions
OpenAI Codex review: Specified ideal liquid/vapour assumptions, Henry/Raoult limits, equilibrium composition and the limits of surface-blocking analogies.
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Ideal and non-ideal solutions
OpenAI Codex review: Corrected azeotrope criteria and fixed-pressure limits, concentration basis and insufficient heat/volume evidence for deviation sign.
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Colligative properties
OpenAI Codex review: Clarified ideal-model assumptions, onset of freezing, osmotic flow, tonicity and practical reverse-osmosis limits.
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Abnormal molar masses
OpenAI Codex review: Distinguished measured van’t Hoff factors from particle counts, corrected ion-pairing claims and recalculated weak-acid dissociation.
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Electrochemical cells
OpenAI Codex read the published lesson, FAQs and practice; corrected model assumptions, scientific overclaims and identified factual errors, and independently checked calculations. New unpublished draft; no simulation changes.
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Galvanic cells
OpenAI Codex read the published lesson, FAQs and practice; corrected model assumptions, scientific overclaims and identified factual errors, and independently checked calculations. New unpublished draft; no simulation changes.
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Nernst equation
OpenAI Codex read the published lesson, FAQs and practice; corrected model assumptions, scientific overclaims and identified factual errors, and independently checked calculations. New unpublished draft; no simulation changes.
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Conductance of electrolytic solutions
OpenAI Codex read the published lesson, FAQs and practice; corrected model assumptions, scientific overclaims and identified factual errors, and independently checked calculations. New unpublished draft; no simulation changes.
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Electrolytic cells and electrolysis
OpenAI Codex read the published lesson, FAQs and practice; corrected model assumptions, scientific overclaims and identified factual errors, and independently checked calculations. New unpublished draft; no simulation changes.
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Batteries
OpenAI Codex read the published lesson, FAQs and practice; corrected model assumptions, scientific overclaims and identified factual errors, and independently checked calculations. New unpublished draft; no simulation changes.
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Fuel cells
OpenAI Codex read the published lesson, FAQs and practice; corrected model assumptions, scientific overclaims and identified factual errors, and independently checked calculations. New unpublished draft; no simulation changes.
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Corrosion
OpenAI Codex read the published lesson, FAQs and practice; corrected model assumptions, scientific overclaims and identified factual errors, and independently checked calculations. New unpublished draft; no simulation changes.
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Rate of a chemical reaction
Clarify rate definitions, signs, phase concentrations and experimental assumptions; correct tangent slope and precision interpretation.
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Factors influencing rate
Correct overall versus partial order, elementary-step molecularity and factor-two kinetics; clarify apparent laws and rate-control assumptions.
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Experiment: iodide and hydrogen peroxide
Correct clock-rate approximation and mechanism inference; clarify endpoint chemistry, dilution controls and practical measurement limits.