Physical Science Formula Sheet
All key formulas and reaction types for AP SSC Class 10 Physical Science — Physics (Ch.9–12) and Chemistry (Ch.1–4). Bookmark this before your BSE AP General Science Paper I exam.
Ch. 1 — Chemical Reactions and Equations
Chemistry- ·Law of Conservation of Mass: mass of reactants = mass of products
- ·Combination: A + B → AB (e.g. 2Mg + O₂ → 2MgO)
- ·Decomposition: AB → A + B (thermal, electrolytic, photolytic)
- ·Displacement: A + BC → AC + B (more reactive A displaces B)
- ·Double Displacement: AB + CD → AD + CB (precipitate/gas/water formed)
- ·Oxidation = loss of electrons / gain of oxygen; Reduction = gain of electrons / loss of oxygen
Ch. 2 — Acids, Bases and Salts
Chemistry- ·Acid + Metal → Salt + H₂ gas (e.g. Zn + H₂SO₄ → ZnSO₄ + H₂↑)
- ·Acid + Metal oxide → Salt + Water (neutralisation type)
- ·Acid + Base → Salt + Water (neutralisation)
- ·Acid + Carbonate → Salt + H₂O + CO₂ (e.g. Na₂CO₃ + HCl → NaCl + H₂O + CO₂)
- ·pH < 7 → acidic; pH = 7 → neutral; pH > 7 → basic
- ·NaOH + HCl → NaCl + H₂O · Ca(OH)₂ + CO₂ → CaCO₃ + H₂O
Ch. 3 — Metals and Non-metals
Chemistry- ·Reactivity series (high→low): K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au
- ·Metals with water: 2Na + 2H₂O → 2NaOH + H₂↑ (cold); Mg + H₂O → MgO + H₂ (steam)
- ·Thermite reaction: 2Al + Fe₂O₃ → Al₂O₃ + 2Fe (displacement)
- ·Ionic bond: formed by transfer of electrons (metal → non-metal)
- ·Corrosion of iron: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O (rust)
- ·Electrovalency = number of electrons lost/gained to form ion
Ch. 4 — Carbon and its Compounds
Chemistry- ·Combustion: CH₄ + 2O₂ → CO₂ + 2H₂O (complete); incomplete → CO + soot
- ·Oxidation: CH₃OH (methanol) → HCOOH (formic acid) [acidic KMnO₄]
- ·Addition reaction: CH₂=CH₂ + H₂ → CH₃–CH₃ (Ni catalyst, hydrogenation)
- ·Substitution: CH₄ + Cl₂ → CH₃Cl + HCl (in presence of sunlight)
- ·Saponification: ester + NaOH → soap (sodium salt of fatty acid) + glycerol
- ·Homologous series: differ by –CH₂– (14 u); same functional group; similar chemical properties
Ch. 9 — Light: Reflection and Refraction
Physics- ·Mirror formula: 1/v + 1/u = 1/f; Focal length f = R/2
- ·Magnification (mirror): m = −v/u = h'/h
- ·Sign convention: distances measured from pole; incident ray direction = positive
- ·Snell's Law: n₁ sin θ₁ = n₂ sin θ₂; n = speed of light in vacuum / speed in medium
- ·Lens formula: 1/v − 1/u = 1/f
- ·Magnification (lens): m = v/u = h'/h
- ·Power of lens: P = 1/f (in metres); unit = dioptre (D)
Ch. 10 — The Human Eye and the Colourful World
Physics- ·Near point of normal eye = 25 cm; Far point = infinity
- ·Myopia (short-sight): image forms in front of retina → corrected by concave lens
- ·Hypermetropia (long-sight): image forms behind retina → corrected by convex lens
- ·Presbyopia: loss of near-point accommodation in old age → bifocal lens
- ·Power of corrective lens for myopia: P = −1/far point (in metres)
- ·Power of corrective lens for hypermetropia: P = 1/near point required − 1/near point actual
- ·Scattering ∝ 1/λ⁴ (Rayleigh scattering): shorter wavelength scatters more (blue sky)
Ch. 11 — Electricity
Physics- ·Ohm's Law: V = IR; R = ρl/A (ρ = resistivity, l = length, A = cross-section area)
- ·Series: R_total = R₁ + R₂ + R₃; current same; voltage divides
- ·Parallel: 1/R_total = 1/R₁ + 1/R₂ + 1/R₃; voltage same; current divides
- ·Electric power: P = VI = I²R = V²/R (unit: watt W)
- ·Electric energy: E = Pt = VIt (unit: joule J; commercial unit: kWh = 3.6 × 10⁶ J)
- ·Heating effect (Joule's law): H = I²Rt
- ·1 kWh = 1 unit of electrical energy consumed
Ch. 12 — Magnetic Effects of Electric Current
Physics- ·Right-hand thumb rule: thumb → current direction, fingers curl → magnetic field direction
- ·Fleming's Left-Hand Rule: Force on current-carrying conductor in magnetic field (motor effect)
- ·Fleming's Right-Hand Rule: Direction of induced current in generator (generator effect)
- ·Faraday's law: induced EMF = −N × dΦ/dt (changing flux induces EMF)
- ·AC frequency in India = 50 Hz; peak voltage ≈ 311 V for 220 V rms supply
- ·Transformer: V_s/V_p = N_s/N_p = I_p/I_s (step-up: N_s > N_p; step-down: N_s < N_p)