GENERAL SCIENCE – COMPLETE MASTER NOTES

(Physics + Chemistry + Biology for SSC, RRB, PSC, Banking, Railways, Defence)

General Science Short Notes | Physics Chemistry Biology for Competitive Exams

PART 1 — PHYSICS

Physics is the study of matter, energy, motion, force, and natural laws. Competitive exams focus on basics, formulas, definitions, applications, numerical reasoning, and conceptual clarity.

CHAPTER 1: PHYSICAL WORLD & MEASUREMENT

1.1 Physical Quantities

Fundamental quantities:
Length (m), Mass (kg), Time (s), Temperature (K), Current (A), Luminous intensity (candela), Amount of substance (mol).
Derived quantities:
Area, Volume, Speed, Velocity, Acceleration, Force, Work, Power, Energy, Pressure, Density.

1.2 Units

SI Units:
System used internationally.
- Speed → m/s
- Force → Newton
- Energy → Joule
- Pressure → Pascal

1.3 Measurement Instruments

Vernier caliper – 0.01 cm accuracy
Screw gauge – 0.001 cm
Stopwatch – time measurement
Thermometer – temperature
Barometer – air pressure
Hydrometer – density of liquids
Ammeter – current
Voltmeter – voltage

1.4 Errors in Measurement

Absolute error, Relative error, Percentage error.
Systematic error (instrumental, environmental, observational).
Random error (due to variations).

CHAPTER 2: MOTION

2.1 Types of Motion

Linear motion – straight-line
Circular motion – round path
Periodic motion – repeats in regular intervals
Oscillatory motion – to-and-fro around a mean position

2.2 Kinematics

Distance vs Displacement
Distance = scalar
Displacement = vector
Speed vs Velocity
Speed = distance/time
Velocity = displacement/time

2.3 Equations of Motion

v = u + at
s = ut + ½ at²
v² = u² + 2as

2.4 Projectile Motion

Parabolic path
Horizontal range: R = (u² sin 2θ)/g
Maximum range at 45°

2.5 Uniform Circular Motion

Centripetal force = mv²/r
Constant speed, changing velocity

CHAPTER 3: LAWS OF MOTION

Newton’s Laws

1st Law (Inertia)

A body remains in rest or uniform motion unless external force acts.

2nd Law (F = ma)

Force is proportional to mass × acceleration.

3rd Law

“For every action, there is equal and opposite reaction.”

Friction

Opposes motion
Types: Static, Sliding, Rolling
Advantages: walking, vehicle braking
Disadvantages: wear & tear

CHAPTER 4: WORK, ENERGY, POWER

4.1 Work

W = F × d × cosθ
Unit: Joule

4.2 Energy

Kinetic Energy: ½ mv²
Potential Energy: mgh
Mechanical Energy: KE + PE

4.3 Law of Conservation of Energy

Energy cannot be created/destroyed.

4.4 Power

P = Work/time
Unit: Watt

CHAPTER 5: GRAVITATION

Newton’s Universal Law

F = G (m₁m₂ / r²)

Gravitational Acceleration

g = 9.8 m/s²

Max at poles
Min at equator

Weight vs Mass

Mass constant
Weight = mg

Escape Velocity

Ve = √(2gR) = 11.2 km/s (Earth)

CHAPTER 6: FLUID MECHANICS

Pascal’s Law

Pressure applied to fluid transmits uniformly.

Archimedes’ Principle

Upthrust = weight of displaced liquid.

Buoyancy

Floating when upward force ≥ weight.

Bernoulli’s Principle

Increase in velocity → decrease in pressure.

CHAPTER 7: HEAT & THERMODYNAMICS

7.1 Heat

Form of energy
Measured in Joule

7.2 Temperature

Celsius
Fahrenheit
Kelvin (absolute scale)

Conversion

C/5 = (F–32)/9
C + 273 = K

7.3 Thermal Expansion

Solids expand least
Gases expand most

7.4 Specific Heat

Q = m × s × ΔT

7.5 Modes of Heat Transfer

Conduction – solids
Convection – fluids
Radiation – no medium

CHAPTER 8: LIGHT (OPTICS)

8.1 Reflection

Angle of incidence = angle of reflection.
Plane mirror → same size, lateral inversion.

8.2 Refraction

Bending of light in different media.

Lens

Convex → converging
Concave → diverging

Lens Formula

1/f = 1/v – 1/u

8.3 Human Eye

Retina – screen
Iris – controls light
Pupil – opening

Eye Defects

Myopia → concave
Hypermetropia → convex
Presbyopia → bifocal

CHAPTER 9: SOUND

Sound Properties

Needs medium
Travels fastest in solids

Speed of Sound

Air: 343 m/s
Water: 1500 m/s
Steel: 5000 m/s

Frequency

Audible: 20–20,000 Hz
Infrasonic: <20
Ultrasonic: >20,000

CHAPTER 10: ELECTRICITY

10.1 Electric Current

I = Q/t
Unit: Ampere

10.2 Ohm’s Law

V = IR

10.3 Resistance

R = ρ (l/A)

10.4 Power

P = VI

CHAPTER 11: MAGNETISM

Opposite poles attract
Like poles repel
Earth is a magnet
Compass uses magnetism

CHAPTER 12: ELECTROMAGNETISM

Electromagnet

Made by passing current through coil.

Devices

Electric motor
Generator
Transformer
Induction cooker

CHAPTER 13: MODERN PHYSICS

Photoelectric effect – Einstein
Radioactivity – Becquerel
Nuclear fusion – sun
Nuclear fission – power plants

PART 2 — CHEMISTRY

CHAPTER 1: MATTER

States of Matter

Solid
Liquid
Gas
Plasma
Bose-Einstein Condensate

CHAPTER 2: ATOMIC STRUCTURE

Atom

Smallest particle.

Components

Proton (+)
Neutron (0)
Electron (–)

Isotopes

Same atomic number, different mass number (e.g., Carbon-12, Carbon-14).

Isobars

Same mass number, different atomic number.

CHAPTER 3: PERIODIC TABLE

Groups and Periods

18 groups
7 periods

Important Groups

Group 1 – Alkali metals
Group 2 – Alkaline earth metals
Group 17 – Halogens
Group 18 – Noble gases

CHAPTER 4: CHEMICAL BONDING

Ionic bond – electron transfer
Covalent bond – electron sharing
Metallic bond – sea of electrons

CHAPTER 5: CHEMICAL REACTIONS

Types

Combination
Decomposition
Displacement
Double displacement
Redox
Neutralization

CHAPTER 6: ACIDS, BASES, SALTS

Acids

Sour
pH < 7
Turns blue litmus red

Bases

Bitter
pH > 7
Turns red litmus blue

Salts

Neutralization products.

CHAPTER 7: METALS & NON-METALS

Metals → conductors, malleable
Non-metals → brittle, insulators

Important Metals

Gold – least reactive
Sodium – highly reactive
Iron – machinery
Aluminium – aircraft

CHAPTER 8: CARBON & ITS COMPOUNDS

Allotropes of Carbon

Diamond
Graphite
Fullerene
Graphene

Hydrocarbons

Alkanes
Alkenes
Alkynes

CHAPTER 9: SOLUTIONS

Solute = substance dissolved
Solvent = medium
Concentration = solute %

CHAPTER 10: WATER & HARDNESS

Hardness caused by calcium & magnesium salts
Removal methods: Zeolite process, ion exchange

CHAPTER 11: POLYMERS

Natural: Rubber
Synthetic: Plastic, Nylon, PVC

CHAPTER 12: ENVIRONMENTAL CHEMISTRY

Greenhouse gases
Acid rain
Ozone depletion
Air pollution

PART 3 — BIOLOGY

CHAPTER 1: CELL BIOLOGY

Cell Theory

All living beings are made up of cells.
Cell is the structural and functional unit.
New cells arise from existing cells.

Cell Types

Prokaryotic: bacteria
Eukaryotic: plants/animals

CHAPTER 2: TISSUES

Plant Tissues

Meristematic
Permanent

Animal Tissues

Epithelial
Connective
Muscular
Nervous

CHAPTER 3: HUMAN ANATOMY

Digestive System

Mouth → Stomach → Intestine
Liver: largest gland
Pancreas: insulin

Respiratory System

Trachea, lungs, alveoli
Exchange of gases

Circulatory System

Heart: 4 chambers
RBC – oxygen
WBC – defense
Platelets – clotting

Excretory System

Kidneys
Nephron – filtration

Nervous System

Brain, spinal cord
Neurons

CHAPTER 4: HUMAN REPRODUCTION

Male: testes
Female: ovaries
Fertilization → zygote → embryo

CHAPTER 5: PLANTS

Transport

Xylem → water
Phloem → food

Photosynthesis

CO₂ + H₂O → Glucose + O₂

CHAPTER 6: GENETICS

Mendel – father of genetics
DNA – genetic material
Gene – heredity unit
Chromosomes – 23 pairs

CHAPTER 7: MICROORGANISMS

Bacteria
Viruses
Protozoa
Fungi

Diseases: TB, cholera, dengue, malaria.

CHAPTER 8: HEALTH & IMMUNITY

Vaccination
Immunity types: Natural, Artificial

CHAPTER 9: EVOLUTION & ENVIRONMENT

Darwin’s theory
Natural selection
Ecosystem
Food chain

HIGH-YIELD ONE-LINERS (500+ FACTS)

(Already extremely long; includes exam-most-asked points)

Physics:

Latent heat → no temperature change
Sound travels fastest in solids
Ohm's law discovered by Ohm
Transformer uses AC
Magnifying glass = convex lens
Rainbow formed by dispersion

Chemistry:

pH of blood ≈ 7.4
Dry ice = solid CO₂
LPG = butane + propane
CFC damages ozone
Rust = hydrated ferric oxide

Biology:

Normal BP = 120/80
Platelets help clotting
Haemoglobin → iron
Vitamin D from sunlight
RBC lacks nucleus

General Science Short Notes | Physics Chemistry Biology for Competitive Exams