Science & Technology - Complete SSC CGL Guide
What is Science & Technology in SSC CGL? These are General Knowledge topics covering Physics, Chemistry, Biology, Everyday Science, Computer Science, and recent technological developments. Essential for SSC CGL Tier I and Tier II exams.
Science & Technology Branches - Must understand for SSC exams
Fundamental constants used in physics calculations
Basic elements and their properties
Basic Science Constants - Important numbers for quick reference
Pro Tip – The 3-Step Science & Technology Mastery Method!
1. Learn Concepts First: Basic principles, formulas, classifications
2. Memorize Key Facts: Discoveries, inventors, dates, applications
3. Practice MCQs Daily: Apply knowledge to actual exam questions
Visit SKY Practice for 1000+ Science & Technology questions with detailed explanations.
1. Physics Basics
Physics Fundamentals: Study of matter, energy, and their interactions. Includes mechanics, thermodynamics, optics, electricity, and modern physics.
Physics Concepts & Laws
Understanding Physical Laws
Physics explains natural phenomena through laws and principles. Important for understanding everyday technology and scientific advancements.
Laws of Motion
• Object at rest stays at rest, in motion stays in motion
• Unless acted upon by external force
Newton's Second Law (F=ma):
• Force = mass × acceleration
• Direction of force = direction of acceleration
Newton's Third Law (Action-Reaction):
• Every action has equal and opposite reaction
• Forces occur in pairs
Discovered by: Sir Isaac Newton (1687)
Electricity & Magnetism
Electrical Power: P = VI = I²R = V²/R
Series Circuit: R = R₁ + R₂ + R₃...
Parallel Circuit: 1/R = 1/R₁ + 1/R₂ + 1/R₃...
Magnetic Effects:
• Right-hand thumb rule for current
• Fleming's left-hand rule (motor)
• Fleming's right-hand rule (generator)
Electromagnetic Induction: Michael Faraday (1831)
Light & Optics
Reflection Laws:
• Angle of incidence = Angle of reflection
• Incident ray, reflected ray, normal in same plane
Refraction Laws (Snell's Law):
• n₁ sinθ₁ = n₂ sinθ₂
• Light bends when changing medium
Lens Formula: 1/f = 1/v - 1/u
Power of lens: P = 1/f (in meters)
Dispersion: Prism separates white light (Newton)
Heat & Thermodynamics
• Conduction: Through solids
• Convection: Through fluids
• Radiation: Through empty space (infrared)
Specific Heat: Q = mcΔT
• Water: 1 cal/g°C or 4186 J/kg°C
Laws of Thermodynamics:
1st: Energy conservation (ΔU = Q - W)
2nd: Entropy increases in isolated systems
3rd: Absolute zero unattainable
Latent Heat: Q = mL (phase change without temp change)
SSC Shortcut: Physics Formulas to Remember
Force: F = ma • Work: W = Fs cosθ • Power: P = W/t
Kinetic Energy: KE = ½mv² • Potential Energy: PE = mgh
Density: ρ = m/V • Pressure: P = F/A • Pressure in liquids: P = hρg
Speed of sound (air): 343 m/s • Speed of light: 3×10⁸ m/s
Ohm's Law: V = IR • Electrical Power: P = VI
Lens formula: 1/f = 1/v - 1/u • Mirror formula: 1/f = 1/u + 1/v
Important Physics Discoveries Table
| Scientist | Discovery/Invention | Year | Significance |
|---|---|---|---|
| Isaac Newton | Laws of Motion, Universal Gravitation | 1687 | Foundation of classical mechanics |
| Albert Einstein | Theory of Relativity (Special & General) | 1905, 1915 | Revolutionized understanding of space-time |
| Michael Faraday | Electromagnetic Induction | 1831 | Basis for electric generators, transformers |
| James Clerk Maxwell | Maxwell's Equations (Electromagnetism) | 1865 | Unified electricity, magnetism, light |
| Marie Curie | Radioactivity (Polonium, Radium) | 1898 | First woman Nobel winner, only in two sciences |
| Niels Bohr | Bohr Model of Atom | 1913 | Quantum theory, electron orbits |
| Galileo Galilei | Telescope observations, kinematics | 1609 | Father of modern observational astronomy |
| C.V. Raman | Raman Effect (light scattering) | 1928 | Nobel Prize 1930, first Asian in science |
Solved Example: Physics
Force is any interaction that changes motion of object
Newton's Second Law: F = ma (force = mass × acceleration)
Step 2: Derive SI unit
Mass SI unit: kilogram (kg)
Acceleration SI unit: meter per second squared (m/s²)
Therefore: Force unit = kg × m/s² = kg·m/s²
This derived unit is named "newton" (N) in honor of Isaac Newton
Step 3: Definition of 1 newton
1 newton is force required to accelerate 1 kg mass at 1 m/s²
Mathematically: 1 N = 1 kg × 1 m/s²
Step 4: Eliminate other options
• Joule (J): Unit of energy or work (1 J = 1 N·m)
• Watt (W): Unit of power (1 W = 1 J/s)
• Pascal (Pa): Unit of pressure (1 Pa = 1 N/m²)
• Coulomb (C): Unit of electric charge
Step 5: Related units
• In CGS system: dyne (1 N = 10⁵ dyne)
• British system: pound-force (1 N ≈ 0.225 lbf)
• Gravitational unit: kilogram-force (1 kgf = 9.8 N)
Step 6: Practical examples
• Apple falling: ~1 N (100 g apple)
• Human weight: ~500-1000 N (50-100 kg person)
• Car accelerating: ~2000 N (1000 kg car at 2 m/s²)
Final Answer: Newton (N)
2. Chemistry Basics
Chemistry Fundamentals: Study of matter, its properties, composition, and changes. Includes elements, compounds, reactions, and periodic table.
Chemical Elements & Reactions
Understanding Chemical Principles
Chemistry explains how substances interact, transform, and combine. Essential for understanding materials, medicines, and industrial processes.
Periodic Table - Important Elements
First 10 elements of periodic table with atomic numbers
1 Periodic Table Organization
Modern version: Henry Moseley (1913) - atomic number basis
Groups (Vertical columns 1-18):
• Group 1: Alkali metals (Li, Na, K, Rb, Cs, Fr)
• Group 2: Alkaline earth metals (Be, Mg, Ca, Sr, Ba, Ra)
• Group 17: Halogens (F, Cl, Br, I, At)
• Group 18: Noble gases (He, Ne, Ar, Kr, Xe, Rn)
Periods (Horizontal rows 1-7):
• Period 1: 2 elements • Period 2 & 3: 8 elements
• Period 4 & 5: 18 elements • Period 6: 32 elements
• Period 7: Incomplete
Blocks: s-block (groups 1-2), p-block (groups 13-18), d-block (groups 3-12), f-block (lanthanides & actinides)
2 Acids, Bases & Salts
• Strong acids: HCl, H₂SO₄, HNO₃
• Weak acids: CH₃COOH (acetic), H₂CO₃ (carbonic)
Bases: pH > 7, bitter taste, turn red litmus blue
• Strong bases: NaOH, KOH, Ca(OH)₂
• Weak bases: NH₄OH (ammonium hydroxide)
pH Scale: 0-14 (0 strongest acid, 7 neutral, 14 strongest base)
Indicators:
• Litmus: Red (acid), Blue (base)
• Phenolphthalein: Colorless (acid), Pink (base)
• Methyl orange: Red (acid), Yellow (base)
Salts: Acid + Base → Salt + Water (neutralization)
Example: HCl + NaOH → NaCl + H₂O
SSC Shortcut: Chemistry Mnemonics
Reactivity series: "Please Stop Calling Me A Zebra, I Like Her Call Smart Goat" (Potassium, Sodium, Calcium, Magnesium, Aluminum, Zinc, Iron, Lead, Copper, Silver, Gold)
pH indicators: "ABC" - Acid: Blue to Red, Base: Red to Blue (for litmus)
Strong acids: "So I Brought No Clean Clothes" (H₂SO₄, HI, HBr, HNO₃, HCl, HClO₄)
Noble gases: "He Never Argued; Krypto Xenon Ran" (He, Ne, Ar, Kr, Xe, Rn)
Diatomic elements: "HOFBrINCl" (Hydrogen, Oxygen, Fluorine, Bromine, Iodine, Nitrogen, Chlorine)
Solved Example: Chemistry
Modern chemistry began with quantitative approach to chemical reactions
Replaced alchemy with scientific methodology
Step 2: Identify key figure
Antoine Lavoisier (1743-1794) is called "father of modern chemistry"
French nobleman and chemist
Executed during French Revolution (1794)
Step 3: Lavoisier's contributions
• Law of Conservation of Mass: Mass neither created nor destroyed in chemical reactions
• Named oxygen (1778) and hydrogen (1783)
• Helped construct metric system
• Wrote first extensive list of elements (33 elements)
• Explained combustion and respiration as oxidation
• Co-authored "Méthode de nomenclature chimique" (1787)
• Wrote "Traité Élémentaire de Chimie" (1789) - first modern chemistry textbook
Step 4: Famous quote
"Nothing is lost, nothing is created, everything is transformed"
Summarizes Law of Conservation of Mass
Step 5: Eliminate other options
• John Dalton: Atomic theory (1803), not father of modern chemistry
• Dmitri Mendeleev: Periodic table (1869), much later
• Robert Boyle: Boyle's law (1662), early work but not modern chemistry founder
• Marie Curie: Radioactivity (1898), much later
Step 6: Tragic end
Lavoisier was guillotined during Reign of Terror
Judge said: "The Republic needs neither scientists nor chemists"
Mathematician Joseph-Louis Lagrange commented: "It took only a moment to sever that head, and perhaps a century will not be sufficient to produce another like it."
Final Answer: Antoine Lavoisier
3. Biology Basics
Biology Fundamentals: Study of living organisms, their structure, function, growth, evolution, and distribution. Includes human body, plants, animals, and microorganisms.
Human Body & Living Organisms
Understanding Life Processes
Biology explains how living organisms function, reproduce, and interact with their environment. Essential for understanding health, medicine, and ecosystems.
Circulatory system pump
4 chambers: 2 atria, 2 ventricles
Beats ~72 times/minute
Pumps ~5 liters blood
Respiratory system
Gas exchange: O₂ in, CO₂ out
Right lung: 3 lobes
Left lung: 2 lobes (space for heart)
Control center
~86 billion neurons
Uses 20% of body's energy
Protected by skull, meninges
Largest internal organ
Detoxification, protein synthesis
Produces bile, stores glycogen
Regenerative capacity
Excretory system
Filter blood, produce urine
Maintain fluid/electrolyte balance
Located retroperitoneal
Digestive system
Stores, mixes food
Produces gastric juice (HCl, enzymes)
pH ~1.5-3.5 (very acidic)
1 Cell Structure & Functions
1. All living things made of cells
2. Cell is basic unit of life
3. New cells come from existing cells
Cell Types:
• Prokaryotic: No nucleus (bacteria, archaea)
• Eukaryotic: Has nucleus (plants, animals, fungi, protists)
Cell Organelles:
• Nucleus: Contains DNA, control center
• Mitochondria: Powerhouse (ATP production)
• Ribosomes: Protein synthesis
• Endoplasmic Reticulum: Protein/lipid transport
• Golgi Apparatus: Packaging, secretion
• Lysosomes: Digestion, waste removal
• Chloroplasts: Photosynthesis (plant cells)
• Cell Wall: Support, protection (plant cells)
Human cells: ~37.2 trillion cells in adult body
2 Digestive System Process
2. Esophagus: Food pipe, peristalsis movement
3. Stomach: HCl kills bacteria, pepsin digests proteins
4. Small Intestine: Major digestion & absorption (6-7 m long)
• Duodenum: Receives bile (liver) & pancreatic juice
• Jejunum: Nutrient absorption
• Ileum: Final absorption
5. Large Intestine: Water absorption, feces formation (1.5 m)
• Cecum, colon, rectum
• Appendix: Vestigial organ
Accessory organs: Liver, gallbladder, pancreas
Enzymes: Amylase (carbs), pepsin/trypsin (proteins), lipase (fats)
SSC Shortcut: Biology Facts & Numbers
Human bones: 206 (adult) • Muscles: ~650
Blood groups: A, B, AB, O (AB universal recipient, O universal donor)
Chromosomes: 46 (23 pairs) • DNA base pairs: A-T, G-C
Heart rate: 72/min • Breathing rate: 12-20/min
Body temperature: 98.6°F (37°C) • Blood pH: 7.35-7.45
Blood volume: 5-6 liters • Brain weight: ~1.4 kg
Lifespan of RBC: 120 days • Lifespan of WBC: Few hours to years
Solved Example: Biology
Glands are organs that produce substances for body use
Two types: Endocrine (hormones into blood) and Exocrine (secretions through ducts)
Step 2: Identify large glands
Major glands in human body:
• Liver: Largest gland (also largest internal organ)
• Pancreas: Both endocrine (insulin) and exocrine (digestive enzymes)
• Thyroid: Endocrine gland in neck
• Pituitary: "Master gland" but very small (pea-sized)
• Adrenal: Above kidneys, produce adrenaline
• Salivary glands: In mouth
• Sweat glands: Throughout skin
Step 3: Liver characteristics
Weight: ~1.5 kg (adult)
Location: Right upper abdomen, below diaphragm
Functions:
1. Detoxification: Removes toxins from blood
2. Protein synthesis: Produces blood proteins
3. Bile production: Aids fat digestion
4. Glycogen storage: Energy reserve
5. Cholesterol regulation
6. Vitamin storage (A, D, B12)
7. Blood clotting factor production
Step 4: Eliminate other options
• Pancreas: Important but smaller (~100g)
• Thyroid: Small butterfly-shaped gland
• Pituitary: Very small (~0.5g)
• Skin: Largest organ but not a gland
Step 5: Liver's unique features
• Only organ that can regenerate (up to 75% can be removed and regrow)
• Dual blood supply: Hepatic artery (oxygen) + Portal vein (nutrients from intestines)
• Produces ~1 liter of bile daily
• Contains Kupffer cells (immune function)
• Processes drugs and alcohol
Step 6: Common liver diseases
• Hepatitis: Inflammation (viral A, B, C, etc.)
• Cirrhosis: Scarring from chronic damage
• Fatty liver disease: From obesity, alcohol
• Liver cancer: Hepatocellular carcinoma
Final Answer: Liver
4. Everyday Science
Applied Science: Practical applications of scientific principles in daily life. Includes household phenomena, common technologies, and scientific reasoning.
Science in Daily Life
Understanding Everyday Phenomena
Everyday science explains common occurrences using basic scientific principles. Important for practical knowledge and logical reasoning.
Cooking Science
Heat transfer: Conduction (pan), convection (oven), radiation (grill)
Chemical changes: Maillard reaction (browning), caramelization
Preservation: Refrigeration, canning, drying, pickling
Fermentation: Bread rising, yogurt, alcohol production
Household Science
Cleaning: Soaps (emulsify grease), detergents (surfactants)
Water purification: Filtration, chlorination, reverse osmosis
Electric appliances: Heating elements, motors, transformers
Plumbing: Water pressure, siphon principle, traps
Transportation Science
Internal combustion: Fuel + air → explosion → motion
Aerodynamics: Lift, drag, thrust, weight
Friction: Brakes, tires, road grip
Navigation: GPS, compass, inertial guidance
1 Common Scientific Phenomena
Why sunset is red? Longer path through atmosphere scatters blue away
Why ice floats? Water expands when freezing (density decreases)
Why metals conduct electricity? Free electrons in metallic bonds
Why rainbow appears? Refraction, dispersion, reflection in water droplets
Why seasons change? Earth's axial tilt (23.5°), not distance from sun
Why we see lightning before thunder? Light faster than sound (3×10⁸ vs 343 m/s)
Why paper burns but iron doesn't? Ignition temperature difference
Pressure cooking: Higher pressure → higher boiling point → faster cooking
Refrigerator cooling: Compression and expansion of refrigerant gas
2 Health & Medicine Basics
• Stimulate immune system without causing disease
• Herd immunity protects community
Antibiotics: Alexander Fleming (penicillin, 1928)
• Kill or inhibit bacteria
• Antibiotic resistance: Overuse leads to superbugs
Vitamins & Deficiencies:
• Vitamin A: Night blindness
• Vitamin B1: Beriberi
• Vitamin C: Scurvy
• Vitamin D: Rickets (children), Osteomalacia (adults)
• Iodine: Goiter
• Iron: Anemia
Common diseases:
• Malaria: Plasmodium parasite, mosquito vector
• Tuberculosis: Mycobacterium tuberculosis, lungs
• Diabetes: Insulin deficiency (Type 1) or resistance (Type 2)
• Hypertension: High blood pressure (>140/90 mmHg)
Solved Example: Everyday Science
Archimedes' Principle: Object immersed in fluid experiences upward buoyant force equal to weight of fluid displaced
Buoyant force = Weight of displaced fluid = ρ_fluid × V_displaced × g
Step 2: Compare iron piece vs ship
• Solid iron piece: Dense (ρ_iron = 7800 kg/m³), displaces small volume of water
• Iron ship: Hollow shape, displaces large volume of water
Step 3: Density comparison
Water density: ρ_water = 1000 kg/m³
Iron density: ρ_iron = 7800 kg/m³
Average density of ship: Much less than iron because of air inside
Step 4: Mathematical explanation
For floating: Weight of object = Weight of water displaced
• Iron piece: Weight > Buoyant force → Sinks
• Ship: Weight = Buoyant force → Floats (because displaced water weight equals ship weight)
Step 5: Shape matters
Ship's shape pushes aside (displaces) large volume of water
This displaced water weighs as much as the entire ship
Even though ship is made of dense material, its overall density (mass/volume) is less than water
Step 6: Real-world application
This principle applies to all floating vessels
Submarines: Control buoyancy by filling/emptying ballast tanks
Ships have Plimsoll line marking safe loading level
Icebergs: ~90% underwater (ρ_ice = 917 kg/m³, ρ_water = 1025 kg/m³ for seawater)
Final Answer: Because the ship displaces a volume of water whose weight equals the weight of the ship (Archimedes' Principle), while a solid iron piece displaces less water than its own weight.
5. Computer Science
Computing Fundamentals: Study of computers, their design, programming, and applications. Includes hardware, software, networks, and internet.
Computer Basics & Programming
Understanding Computer Systems
Computer science encompasses everything from basic computer operations to advanced programming and networking. Essential in today's digital world.
Computer Generations Timeline
Evolution of computer technology over generations
1 Computer Hardware Components
Output Devices: Monitor, printer, speakers, projector
Processing Unit: CPU (Central Processing Unit)
• ALU: Arithmetic Logic Unit
• CU: Control Unit
• Registers: Temporary storage
Memory:
• RAM: Random Access Memory (volatile, fast)
• ROM: Read Only Memory (non-volatile, permanent)
• Cache: Very fast memory between CPU and RAM
• Storage: HDD, SSD, optical drives
Motherboard: Main circuit board connecting all components
Ports: USB, HDMI, Ethernet, audio, VGA
2 Software & Programming
Application Software: Word processors, browsers, media players
Programming Languages:
• Low-level: Assembly, Machine code
• High-level: Python, Java, C++, JavaScript
Programming Concepts:
• Algorithm: Step-by-step procedure
• Variable: Storage location with name
• Function: Reusable code block
• Loop: Repeated execution
• Condition: Decision making (if-else)
Internet Basics: TCP/IP, HTTP, FTP, DNS, URL, IP address
Web Technologies: HTML, CSS, JavaScript, PHP, SQL
SSC Shortcut: Computer Terminology
CPU: Central Processing Unit • RAM: Random Access Memory
ROM: Read Only Memory • BIOS: Basic Input Output System
OS: Operating System • GUI: Graphical User Interface
URL: Uniform Resource Locator • HTML: HyperText Markup Language
HTTP: HyperText Transfer Protocol • FTP: File Transfer Protocol
DNS: Domain Name System • IP: Internet Protocol
LAN: Local Area Network • WAN: Wide Area Network
WiFi: Wireless Fidelity • Bluetooth: Short-range wireless
Solved Example: Computer Science
HTML is fundamental technology for creating web pages
Used with CSS (styling) and JavaScript (interactivity)
Step 2: Full form
HTML = HyperText Markup Language
• HyperText: Text with links to other text (hyperlinks)
• Markup: Annotating text to define structure and presentation
• Language: Formal system of communication
Step 3: History of HTML
Created by: Tim Berners-Lee in 1991
Original purpose: Share scientific documents at CERN
First version: HTML 1.0 (1993)
Current standard: HTML5 (2014)
Maintained by: World Wide Web Consortium (W3C)
Step 4: How HTML works
Uses tags enclosed in angle brackets:
Basic structure:
<html>
<head>...</head>
<body>...</body>
</html>
Step 5: Common HTML tags
• <h1> to <h6>: Headings
• <p>: Paragraph
• <a>: Anchor (link)
• <img>: Image
• <ul>, <ol>, <li>: Lists
• <table>, <tr>, <td>: Tables
• <div>: Division/container
• <span>: Inline container
Step 6: Eliminate incorrect options
• HyperText Machine Language: Incorrect
• HighText Markup Language: Incorrect
• HyperTool Markup Language: Incorrect
• HyperText Markup Language: Correct
Step 7: Related technologies
• CSS: Cascading Style Sheets (styling)
• JavaScript: Programming for interactivity
• XML: eXtensible Markup Language (data)
• XHTML: XML-based HTML
Final Answer: HyperText Markup Language
6. Technology Updates
Recent Advancements: Latest developments in technology including AI, robotics, biotechnology, nanotechnology, and renewable energy.
Emerging Technologies
Cutting-Edge Technological Developments
Technology is evolving rapidly with breakthroughs in various fields. Important for current affairs and understanding future trends.
Artificial Intelligence
Machine Learning: Algorithms learn from data
Neural Networks: Brain-inspired computing
Natural Language Processing: Computers understand human language
Computer Vision: Image and video analysis
Biotechnology
Genetic Engineering: CRISPR, gene editing
Synthetic Biology: Designing biological systems
Stem Cell Research: Regenerative medicine
Bioinformatics: Biological data analysis
Renewable Energy
Solar Power: Photovoltaic cells, solar thermal
Wind Energy: Turbines, offshore farms
Hydrogen Fuel: Fuel cells, green hydrogen
Energy Storage: Batteries, pumped hydro
1 Recent Indian Technological Achievements
• Chandrayaan-3: Moon landing (2023)
• Aditya-L1: Sun mission (2023)
• Gaganyaan: Human spaceflight program (upcoming)
• NavIC: Indian regional navigation system
Digital India Initiatives:
• Aadhaar: World's largest biometric ID system
• UPI: Unified Payments Interface (revolutionized digital payments)
• CoWIN: COVID vaccine management platform
• DigiLocker: Digital document storage
Defense Technology (DRDO):
• Tejas: Indigenous fighter aircraft
• Agni/V missiles: Ballistic missile systems
• INS Vikrant: Indigenous aircraft carrier
• Dhanush artillery gun
2 Global Technological Trends
• Uses qubits (quantum bits) instead of classical bits
• Can solve certain problems exponentially faster
• Applications: Cryptography, drug discovery, optimization
• Leaders: Google, IBM, China, USA
5G & Beyond:
• 5G: High speed, low latency wireless
• 6G: Research stage, terahertz frequencies
• IoT: Internet of Things (connected devices)
Blockchain & Cryptocurrency:
• Blockchain: Decentralized, immutable ledger
• Bitcoin: First cryptocurrency (2009)
• Ethereum: Smart contracts platform
• CBDC: Central Bank Digital Currency
Metaverse: Virtual shared spaces using VR/AR
Solved Example: Technology Updates
India has conducted multiple Moon missions through ISRO
Chandrayaan program: India's lunar exploration program
Step 2: Identify specific mission
Chandrayaan-3 successfully landed on Moon's south pole on 23 August 2023
Landed at: ~69.37°S, 32.35°E coordinates
Time: 18:04 IST (12:34 UTC)
Step 3: Mission details
• Launched: 14 July 2023 from Sriharikota
• Launch vehicle: LVM3-M4
• Components: Propulsion module, lander (Vikram), rover (Pragyan)
• Objectives: Soft landing, rover operations, in-situ experiments
• Cost: ~₹615 crore (approx $75 million)
Step 4: Historical significance
• First country to land near lunar south pole
• Fourth country to achieve soft landing on Moon (after USSR, USA, China)
• First country to land on Moon's south pole region
• Came after Chandrayaan-2 crash landing (2019)
Step 5: Scientific instruments
Lander (Vikram):
• ChaSTE: Chandra's Surface Thermophysical Experiment
• ILSA: Instrument for Lunar Seismic Activity
• LP: Langmuir Probe
• RAMBHA: Radio Anatomy of Moon Bound Hypersensitive ionosphere and Atmosphere
Rover (Pragyan):
• APXS: Alpha Particle X-ray Spectrometer
• LIBS: Laser Induced Breakdown Spectroscope
Step 6: Previous Chandrayaan missions
• Chandrayaan-1 (2008): Orbiter, discovered water molecules on Moon
• Chandrayaan-2 (2019): Orbiter successful, lander crashed
Step 7: Global context
Russia's Luna-25 crashed days before Chandrayaan-3 landing
USA's Artemis program aims to return humans to Moon
China's Chang'e program has multiple successful missions
Final Answer: Chandrayaan-3
7. Space Science & Astronomy
Space Exploration: Study of universe, celestial bodies, space missions, and astronomical phenomena. Includes ISRO achievements and international space programs.
Astronomy & Space Missions
Understanding the Universe
Space science explores planets, stars, galaxies, and the cosmos. Important for understanding our place in the universe and technological spin-offs.
Solar System Planets
Solar System: Sun + 8 Planets
Planets in order from Sun: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
1 Important Space Missions
• Launched: 1998
• Orbit: 400 km altitude, 51.6° inclination
• Speed: 28,000 km/h, orbits Earth every 90 minutes
• Partners: NASA, Roscosmos, ESA, JAXA, CSA
NASA's Artemis Program: Return humans to Moon by 2025
James Webb Space Telescope (JWST): Launched 2021, infrared telescope
Mars Rovers: Curiosity (2012), Perseverance (2021)
Voyager Program: Voyager 1 & 2 (1977), entered interstellar space
Indian Space Missions (ISRO):
• Aryabhata: First Indian satellite (1975)
• SLV-3: First Indian launch vehicle (1980)
• PSLV: Polar Satellite Launch Vehicle (1993)
• GSLV: Geosynchronous Satellite Launch Vehicle (2001)
• Mars Orbiter Mission (Mangalyaan): 2013, first Asian at Mars
• AstroSat: First Indian space telescope (2015)
2 Astronomical Concepts
Black Hole: Region where gravity prevents anything, including light, from escaping
Supernova: Explosive death of massive star
Neutron Star: Collapsed core of massive star after supernova
Pulsar: Rotating neutron star emitting beams of radiation
Galaxy Types:
• Spiral: Milky Way, Andromeda
• Elliptical: Football-shaped, old stars
• Irregular: No definite shape
Big Bang Theory: Universe began ~13.8 billion years ago from hot, dense state
Dark Matter: Invisible matter affecting galaxy rotation (27% of universe)
Dark Energy: Unknown energy causing universe expansion acceleration (68% of universe)
Exoplanets: Planets orbiting other stars, thousands discovered
Solved Example: Space Science
Indian Space Research Organisation (ISRO) founded in 1969
First Chairman: Dr. Vikram Sarabhai (father of Indian space program)
India's space journey began with satellite launch in 1970s
Step 2: Identify first satellite
Aryabhata was India's first satellite
Named after ancient Indian mathematician-astronomer Aryabhata
Launched: 19 April 1975
Launch site: Kapustin Yar, Russia (then Soviet Union)
Launch vehicle: Soviet Kosmos-3M rocket
Step 3: Satellite specifications
• Shape: 26-faced polyhedron (1.4 m diameter)
• Weight: 360 kg
• Power: Solar panels (46 W)
• Orbit: Near-circular, 619 km × 562 km, 50.7° inclination
• Mission life: Designed for 6 months, operated for 17 years
• Re-entered: 11 February 1992
Step 4: Scientific objectives
• Study of Earth's ionosphere
• Solar physics
• X-ray astronomy
• Conducting experiments in gamma-ray astronomy
Unfortunately, satellite stopped working after 5 days due to power failure
Step 5: Historical context
Project approved in 1972 by Government of India
Built by ISRO with some assistance from Soviet Union
Cost: ₹3 crore (approximately)
Marked India's entry into space age
Paved way for indigenous satellite and launch vehicle development
Step 6: Subsequent developments
• First Indian launch: Rohini RS-1 (1980) by SLV-3
• First communication satellite: APPLE (1981)
• First remote sensing satellite: IRS-1A (1988)
• First lunar mission: Chandrayaan-1 (2008)
• First Mars mission: Mars Orbiter Mission (2013)
Step 7: Eliminate other options
• INSAT: Indian National Satellite System (1983 onwards)
• Bhaskara: Earth observation satellite (1979), not first
• Rohini: First satellite launched by Indian rocket (1980)
• Kalpana-1: Weather satellite (2002), named after Kalpana Chawla
Final Answer: Aryabhata
8. Defence Technology
Military Technology: Weapons, vehicles, communication systems, and other technologies developed for defense purposes. Includes indigenous developments and imports.
Defence Systems & Weapons
Modern Defence Technologies
Defence technology encompasses everything from small arms to nuclear weapons, from tanks to fighter jets, and from radars to cybersecurity.
Air Defence Systems
Fighter Aircraft: Tejas, Rafale, Sukhoi, Mirage
Missile Systems: Akash, S-400, Patriot
Radars: Phalcon AWACS, indigenous radars
UAVs: Rustom, Nishant, Heron
Naval Systems
Aircraft Carriers: INS Vikramaditya, INS Vikrant
Submarines: INS Arihant (nuclear), Scorpène class
Destroyers/Frigates: Kolkata class, Shivalik class
Missile Systems: BrahMos, Barak
Army Systems
Battle Tanks: Arjun, T-90, T-72
Artillery: Dhanush, M777, K9 Vajra
Missiles: Prithvi, Agni, Nag, Helina
Small Arms: INSAS rifle, Sig Sauer
1 Indigenous Defence Developments
• Agni series: Ballistic missiles (Agni-I to Agni-V)
• Prithvi: Short-range ballistic missile
• Akash: Medium-range surface-to-air missile
• Nag: Third-generation anti-tank guided missile
• BrahMos: Supersonic cruise missile (joint with Russia)
Indigenous Platforms:
• Tejas: Light combat aircraft (HAL)
• Arjun: Main battle tank (DRDO)
• INS Vikrant: Indigenous aircraft carrier
• INS Arihant: Nuclear-powered ballistic missile submarine
• Advanced Towed Artillery Gun System (ATAGS)
Electronics & Sensors:
• NETRA: Airborne early warning system
• Various radars and electronic warfare systems
2 Defence Organizations & Exercises
• Indian Army: 1.4 million active personnel
• Indian Navy: 67,000 personnel, 150+ ships
• Indian Air Force: 140,000 personnel, 1700+ aircraft
• Indian Coast Guard
• Strategic Forces Command (nuclear)
Defence PSUs & Organizations:
• DRDO: Defence Research and Development Organisation
• HAL: Hindustan Aeronautics Limited
• BEL: Bharat Electronics Limited
• BDL: Bharat Dynamics Limited
• OFB: Ordnance Factory Board (now 7 corporations)
Military Exercises:
• With USA: Malabar (naval), Yudh Abhyas (army)
• With Russia: Indra (tri-services)
• With France: Varuna (naval), Garuda (air force)
• With UK: Konkan (naval), Ajeya Warrior (army)
• Regional: SIMBEX (Singapore), SAMPRITI (Bangladesh)
Solved Example: Defence Technology
India has been developing nuclear submarine capability for decades
Part of nuclear triad (land, air, sea-based nuclear delivery)
Project codenamed Advanced Technology Vessel (ATV)
Step 2: Identify first indigenous nuclear sub
INS Arihant is India's first indigenously developed nuclear-powered submarine
Name meaning: "Slayer of Enemies" in Sanskrit
Launched: 26 July 2009 (anniversary of Vijay Diwas)
Commissioned: August 2016
Builder: Shipbuilding Centre, Visakhapatnam
Step 3: Technical specifications
• Type: Nuclear-powered ballistic missile submarine (SSBN)
• Displacement: 6,000 tons (surfaced)
• Length: 111 meters
• Propulsion: Pressurized water reactor (83 MW)
• Speed: 12-15 knots (surface), 24 knots (submerged)
• Range: Unlimited (nuclear powered)
• Endurance: Can stay submerged for months
• Crew: 95-100 personnel
• Armament: 12x K-15 Sagarika or 4x K-4 ballistic missiles
Step 4: Strategic significance
• Completes India's nuclear triad (land-based missiles, aircraft, submarines)
• Provides second-strike capability (survivability after first strike)
• Deterrence against nuclear adversaries
• Makes India sixth country with SSBN capability (after USA, Russia, UK, France, China)
Step 5: Development history
• Project started: 1970s
• Reactor developed: Bhabha Atomic Research Centre (BARC)
• Design assistance: Russia provided design consultancy
• Sea trials: Began December 2014
• First deterrence patrol: November 2018
• Cost: ~₹90,000 crore (entire ATV program)
Step 6: Follow-on submarines
• INS Arighat: Second Arihant-class, launched 2017
• S4, S4*: Under construction, larger with more missiles
• SSN program: Nuclear-powered attack submarines (under development)
Step 7: Eliminate other options
• INS Chakra: Russian Akula-class nuclear submarine (leased)
• INS Sindhughosh: Kilo-class diesel-electric submarine (Russian)
• INS Shishumar: German Type 209 submarine
• INS Kalvari: French Scorpène-class submarine
Final Answer: INS Arihant
9. SSC Shortcuts & Memory Techniques
Exam Strategy: Science & Technology have many facts, formulas, discoveries. Use these techniques to remember effectively.
Memory Techniques for Science & Technology
Remembering Facts & Formulas
Use mnemonics, acronyms, associations, and visualization to remember numerous discoveries, formulas, and technological terms.
Mnemonics for Discoveries
1st: Inertia, 2nd: F=ma, 3rd: Action-Reaction
Planets order: "My Very Educated Mother Just Served Us Noodles"
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Taxonomy hierarchy: "Dear King Philip Came Over For Good Soup"
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Electromagnetic spectrum: "Raging Martians Invaded Venus Using X-ray Guns"
Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma
Scientists & Discoveries
Einstein: Relativity, E=mc² (1905, 1915)
Darwin: Evolution, natural selection (1859)
Curie: Radioactivity, radium (1898)
Faraday: Electromagnetic induction (1831)
Mendeleev: Periodic table (1869)
Watson & Crick: DNA structure (1953)
Berners-Lee: World Wide Web (1989)
Indian scientists: C.V. Raman, S.N. Bose, H.J. Bhabha, Vikram Sarabhai
Important Formulas
Chemistry: pH=-log[H⁺], PV=nRT, C=Q/V
Biology: DNA: A-T, G-C; Blood groups: A, B, AB, O
Computer storage:
1 Byte = 8 bits
1 KB = 1024 Bytes
1 MB = 1024 KB
1 GB = 1024 MB
1 TB = 1024 GB
Internet speeds: Mbps = megabits per second, MBps = megabytes per second
Time Management
• Formula recall: 30 sec
• Discovery/scientist: 45 sec
• Application/concept: 60 sec
Technology Questions: 45-60 seconds
• Term definition: 30 sec
• Recent development: 45 sec
• Technical detail: 60 sec
Strategy:
• Direct factual: Do first
• Formula-based: Do if sure
• Application-based: Visualize, eliminate
• Guess if >90 sec without progress
Total: 10-12 minutes for 8-10 questions
SSC Shortcut: Common Question Patterns
Pattern 1: "Who discovered/invented..." (Scientists, discoveries)
Pattern 2: "What is the formula for..." (Physics, chemistry formulas)
Pattern 3: "Which is the largest/smallest..." (Body organs, planets, elements)
Pattern 4: "Full form of..." (Acronyms in technology)
Pattern 5: "Recent development in..." (Space, defense, digital technology)
Pattern 6: "Disease X is caused by deficiency of..." (Vitamins, minerals)
Pattern 7: "Device X works on principle of..." (Scientific principles)
Memory tip: Practice each pattern with previous year questions
10. Practice Exercises
Hands-on Practice: Apply what you've learned with these SSC-level questions.
Interactive Practice Questions
Practice Approach
Time yourself: 60 seconds per question. Apply elimination technique for factual questions.
Practice Question 1: Physics
Practice Question 2: Biology
Practice Question 3: Technology
SSC Shortcut: Practice Strategy
Daily practice: 10 science + 10 technology questions daily
Revision cycle: Revise formulas weekly, discoveries bi-weekly
Current affairs: Weekly update on science/tech developments
Previous papers: Solve last 5 years' SSC science-technology questions
Mixed practice: Practice all topics randomly to avoid pattern recognition
Time management: Aim for 45 seconds per factual question, 60 seconds per application question
Ready to Master Science & Technology?
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Frequently Asked Questions
Q1: How many science & technology questions in SSC CGL?
Answer: Typically 8-12 questions in Tier I. Science: 4-6 questions (Physics, Chemistry, Biology). Technology: 4-6 questions (Computers, recent developments).
Q2: What are the most important formulas to remember?
Answer: F=ma, W=Fd, P=VI, V=IR, pH=-log[H⁺], speed of light=3×10⁸ m/s, g=9.8 m/s², 1 cal=4.2 J, E=mc².
Q3: How to remember all discoveries and scientists?
Answer: Use mnemonics, create timeline charts, associate discoveries with their year or application. Focus on: Newton, Einstein, Faraday, Curie, Darwin, Mendeleev.
Q4: What technology topics are most frequently asked?
Answer: Computer basics (hardware, software, internet), recent space missions (ISRO), defence technology, digital India initiatives, AI/robotics basics.
Q5: How to prepare for current affairs in science & technology?
Answer: Follow: Recent ISRO missions, new scientific discoveries, technology awards (Nobel, Shanti Swarup Bhatnagar), government tech initiatives, major tech company announcements.
Q6: Best way to improve science & technology score?
Answer: 1) Understand concepts rather than rote memorization, 2) Practice application-based questions, 3) Create formula sheets for quick revision, 4) Follow monthly science magazines/websites, 5) Solve previous year papers.
Final Exam Strategy for Science & Technology
Time Allocation: Total 12-15 minutes for 8-12 questions.
Priority Order: 1) Direct factual questions, 2) Formula-based questions, 3) Recent developments questions, 4) Application/conceptual questions.
Accuracy Check: For science, verify formulas and units. For technology, verify full forms and recent dates.
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