Quick Revision Notes

---
name: quick-revision-notes
description: Ultra-condensed 1-page summaries per subject for last-minute revision. Not for learning — for RECALL of what's already learned. The night-before-exam file.
---

# Quick Revision Notes — Last-Minute Scan File

## Mathematics — Key Points Only
```
• Real Numbers: HCF×LCM = product. Euclid's lemma: a=bq+r
• Polynomials: sum=-b/a, product=c/a (quadratic)
• Linear Eq: substitution, elimination, cross-multiplication
• Quadratic: x=(-b±√D)/2a, D=b²-4ac, D≥0 for real roots
• AP: aₙ=a+(n-1)d, Sₙ=n/2[2a+(n-1)d]
• Triangles: AA/SAS/SSS similarity, BPT, Pythagoras
• Coordinate: distance=√[(x₂-x₁)²+(y₂-y₁)²], mid=((x₁+x₂)/2,(y₁+y₂)/2)
• Trig: sin²+cos²=1, 1+tan²=sec², 1+cot²=cosec²
• Circle: tangent⊥radius, tangents from external point are equal
• Mensuration: CSA/TSA/Volume for cylinder, cone, sphere, frustum
• Statistics: mean(3 methods), median=l+[(n/2-cf)/f]×h, mode=l+[(f₁-f₀)/(2f₁-f₀-f₂)]×h
• Probability: P(E)=favourable/total, P(E)+P(Ē)=1
```

## Science — Key Points Only
```
CHEMISTRY:
• Reactions: combination, decomposition, displacement, double displacement, redox
• pH: 0-14, <7=acid, 7=neutral, >7=base
• Metals: reactivity series K>Na>Ca>Mg>Al>Zn>Fe>H>Cu>Ag>Au
• Carbon: tetravalency, catenation, isomers, homologous series (+CH₂)
• STATE SYMBOLS: (s)(l)(g)(aq) — ALWAYS WRITE

PHYSICS:
• V=IR, P=VI=I²R=V²/R, E=Pt, 1kWh=3.6×10⁶J
• Series: R=R₁+R₂, Parallel: 1/R=1/R₁+1/R₂
• Mirror: 1/v+1/u=1/f, m=-v/u (sign convention!)
• Lens: 1/v-1/u=1/f, P=1/f(in m)
• Myopia→concave lens, Hypermetropia→convex lens
• Fleming's Left(motor), Right(generator)

BIOLOGY:
• Nutrition: autotrophic(plants), heterotrophic(animals)
• Respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP
• Heart: 4 chambers, double circulation (pulmonary+systemic)
• Excretion: kidney→nephron→Bowman's capsule→tubule
• Reproduction: budding, fission, regeneration (asexual); flower parts (sexual)
• Heredity: Mendel's laws, dominant/recessive, XX/XY sex determination
• Evolution: natural selection, speciation, fossil evidence
• Environment: food chain, 10% energy transfer, biodegradable/non-biodegradable
```

## Social Science — Key Points Only
```
HISTORY:
• Nationalism: French Revolution → Vienna Congress → unification of Italy/Germany
• India: 1885(INC) → 1905(Swadeshi) → 1920(NCM) → 1930(CDM) → 1942(QIM) → 1947
• Print: Gutenberg press → Indian newspapers → role in nationalism

GEOGRAPHY:
• Resources: renewable/non-renewable, national/international
• Soil types: alluvial, black, red, laterite (know characteristics)
• Crops: kharif(monsoon), rabi(winter), zaid(summer)
• Minerals: iron ore, manganese, mica, limestone locations
• Industries: iron-steel, cotton textile, IT, sugar

ECONOMICS:
• Development: per capita income, HDI, sustainable development
• Sectors: primary/secondary/tertiary, organized/unorganized
• Money & Credit: formal(banks) vs informal(moneylender)
• Globalisation: MNCs, WTO, SEZs, liberalization 1991

POLITICAL SCIENCE:
• Power sharing: why desirable, forms (horizontal, vertical, social, political)
• Federalism: holding together vs coming together, 3 lists
• Democracy outcomes: accountable, legitimate, transparent
• Political parties: BJP, INC, CPI(M), BSP + regional parties
```

## English — Key Points Only
```
FIRST FLIGHT: Mandela, Anne Frank, Lencho, Bholi, Natalya, Lomov
FOOTPRINTS: Griselda, Hack Driver, Matilda (Necklace), Tricki (Dog)
WRITING: Letter(format!), Analytical paragraph(data-based), Article(title+byline)
GRAMMAR: Tense conversion, Reported speech, Modals, Subject-verb agreement
```

## Tamil — Key Points Only
```
• Vetrumai: 8 cases (ஐ, ஆல், கு, இன், அது, இல், விளி)
• Vallinam: க,ச,ட,த,ப,ற | Mellinam: ங,ஞ,ண,ந,ம,ன
• Ani: உவமை, சிலேடை, தற்குறிப்பேற்றம்
• Thirukkural: அறம், பொருள், இன்பம்
```