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!

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)