Important Formulas, Units & Definitions – CBSE & IGCSE

The ultimate resource for all-important formulas, key units, and definitions—your quick revision tool for CBSE & IGCSE. Perfect for board exams, Olympiads, JEE, NEET, NTSE, and daily homework. Use this to boost accuracy, save time, and master every subject!

How to Revise Formulas & Units?

  • Make personalized flashcards or quick sticky notes for tough formulas and review them daily.
  • Group similar formulas—such as motion/energy, acids/bases, area/volume, etc.—for quick association.
  • Practice by writing and solving questions with the formulas; never memorize in isolation.
  • Use memory tricks and mnemonics for complex definitions and lists.
  • Before every test, do a “rapid-fire” recall session—speak or write as many formulas as you can remember.

Physics: Common Units & Measurements

Quantity Unit (SI) Symbol
Force Newton N
Energy/Work Joule J
Power Watt W
Charge Coulomb C
Potential Difference Volt V
Frequency Hertz Hz

Chemistry: Essential Units & Constants

Quantity Unit/Symbol Value/Notes
Amount of Substance Mole (mol) 6.022 x 1023 particles (Avogadro's Number)
Concentration mol/L Molarity (M)
Gas Constant R 8.314 J mol-1 K-1
Pressure Pascal (Pa), atm 1 atm = 101325 Pa
Volume (gas) dm3, L 1 dm3 = 1 L

Maths: Key Formula Categories & Units

Topic Representative Formula Unit (if any)
Area of Circle A = πr² m², cm²
Quadratic Formula x = (-b ± √(b²-4ac))/(2a)
Slope of a Line m = (y₂ - y₁)/(x₂ - x₁)
Pythagoras Theorem a² + b² = c² units²
Surface Area (Cuboid) 2(lb + bh + hl) m², cm²

Biology: Essential Terms & Units

Process/Quantity Unit/Scale Key Notes
Cell Size Micrometre (μm) 1 μm = 10-6 m
Enzyme Activity Katal (kat) Rate of catalysis
Genetic Information Base pairs Measured in bp, kbp, Mbp
Blood Volume (human) Litre (L) ~5 L in adults

English: Key Literary & Grammar Terms

  • Noun: Name of a person, place, thing, or idea.
  • Simile: Comparison using 'like' or 'as' (e.g., "brave as a lion").
  • Metaphor: Direct comparison without 'like' or 'as' (e.g., "time is a thief").
  • Alliteration: Repetition of consonant sounds at the start of words ("She sells sea shells").
  • Passive Voice: Subject receives the action ("The letter was written by her.").
  • Tense: The time of action—past, present, future.
  • Antonym: A word opposite in meaning ("hot" vs. "cold").

Social Science: Essential Terms & Measures

Term/Index Meaning/Unit Use
GDP Gross Domestic Product (₹, $) Economic output of a country
Literacy Rate % % of people above age 7 who can read & write
Democracy System of government People rule through voting
Longitude/Latitude Degrees (°) Geographical location on earth

Key Definitions Across Subjects

  • Displacement (Physics): The shortest distance between initial and final position of an object, with direction.
  • Oxidation (Chemistry): The process where a substance loses electrons (or gains oxygen).
  • Reduction (Chemistry): The process where a substance gains electrons (or loses oxygen).
  • Power (Physics): The rate at which work is done or energy is transferred (Power = Work/Time).
  • Photosynthesis (Biology): The process by which green plants use sunlight to convert water and CO2 into glucose and O2.
  • Allele (Biology): One of two or more alternative forms of a gene.
  • Transpiration (Biology): Loss of water vapor from aerial parts of plants, mainly through stomata.
  • Polynomials (Math): An algebraic expression consisting of variables and coefficients, involving only non-negative integer powers of variables.
  • Probability (Math): A measure of how likely an event is to occur, ranging from 0 (impossible) to 1 (certain).
  • Subject (English): The person or thing that performs the action in a sentence.
  • Active Voice (English): When the subject performs the action (e.g., "He wrote a letter").
  • Democracy (Social Science): A form of government where the people have the authority to choose their governing legislation.
  • Secularism (Social Science): The principle of separation of the state from religious institutions.
  • Market Economy (Social Science): An economic system in which supply and demand regulate production and labor as opposed to government intervention.
  • Acceleration (Physics): The rate of change of velocity per unit time (a = Δv/Δt).
  • Mole (Chemistry): The amount of substance containing Avogadro's number (6.022 × 1023) of particles.
  • Genotype (Biology): The genetic constitution of an organism.
  • Mean (Math): The sum of a set of numbers divided by the number of elements; also known as average.
  • Quadratic Equation (Math): An equation of the form ax² + bx + c = 0, where a ≠ 0.
  • Longitude (Social Science): The angular distance east or west of the Prime Meridian, measured in degrees.
  • Metaphor (English): A figure of speech that describes an object or action as something else, even though it is not literally applicable.
  • Biodegradable (Biology): Capable of being decomposed by bacteria or other living organisms.
  • Enthalpy (Chemistry): A measure of the total energy of a thermodynamic system, including internal energy and the product of pressure and volume.
  • Vector (Physics): A quantity that has both magnitude and direction.

Important Formula Sheets (Quick Access)

CBSE

IGCSE

Other Boards (IB, ICSE, State Boards)

Resources for IB, ICSE, and State Boards are being updated. Visit Hodu Academy regularly or contact us for custom requests.

Keep revising, practicing, and testing yourself with these resources for top exam results. For more tips and free downloads, explore Hodu Academy.
Last modified: Monday, 7 July 2025, 7:34 PM