TNPSC Group II & IIA
Unit I: General Science – Detailed Study Material
Preliminary Examination | Weightage: 5 Questions
1. Scientific Knowledge & Scientific Temper
What is Scientific Knowledge?
Scientific knowledge is the understanding gained through systematic observation, experimentation, evidence collection, and logical reasoning. It is objective, testable, and open to revision when new evidence emerges.
Scientific Temper
Scientific temper refers to an individual’s attitude of logical thinking, rational enquiry, and rejection of superstition and blind belief. It was strongly advocated by former Indian Prime Minister Jawaharlal Nehru.
- Encourages questioning and critical thinking
- Promotes evidence-based decisions
- Helps fight superstitions and pseudoscience
- Essential for the progress of society and nation
Free 20 Marks Test (Unit I): CLICK HERE
Rote Learning vs Conceptual Learning
| Aspect | Rote Learning | Conceptual Learning |
|---|---|---|
| Method | Memorising facts without understanding | Understanding the ‘why’ and ‘how’ |
| Retention | Short-term | Long-term |
| Application | Difficult to apply in new situations | Easy to apply and analyse |
| Preference in TNPSC | Less useful | Highly preferred |
2. Nature of the Universe
- The Universe is vast, dynamic, and continuously expanding.
- Big Bang Theory is the most accepted theory about the origin of the Universe (occurred about 13.8 billion years ago).
- Our Solar System is part of the Milky Way Galaxy.
- There are billions of galaxies in the observable universe.
Solar System – Quick Facts
- Sun – Centre of the Solar System (Star)
- 8 Planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
- Earth is the only planet known to support life
- Jupiter is the largest planet
- Mercury is the smallest and closest to the Sun
- Light Year = Distance travelled by light in one year (approximately 9.46 × 1012 km)
3. General Scientific Laws & Mechanics
Important Scientific Laws
- Newton’s First Law – Law of Inertia
- Newton’s Second Law – F = ma
- Newton’s Third Law – Action and Reaction are equal and opposite
- Law of Gravitation – Every particle attracts every other particle
- Law of Conservation of Energy – Energy can neither be created nor destroyed
- Ohm’s Law – V = IR
- Boyle’s Law – At constant temperature, Pressure × Volume = Constant
Mechanics – Key Concepts
- Force = Mass × Acceleration
- Work = Force × Displacement
- Power = Work / Time
- Kinetic Energy = ½ mv²
- Potential Energy = mgh
- Distance vs Displacement, Speed vs Velocity, Acceleration
Free 20 Marks Test (Unit I): CLICK HERE
4. Everyday Applications of Scientific Principles
| Branch | Everyday Applications |
|---|---|
| Mechanics | Vehicles, machines, elevators, sports, construction, tools |
| Electricity | Fans, lights, heaters, mobile chargers, electric trains |
| Magnetism | Compass, MRI machines, speakers, electric motors, maglev trains |
| Light | Mirrors, lenses, cameras, microscopes, fibre optic cables, solar panels |
| Sound | Microphone, loudspeaker, sonar, ultrasound scanning, hearing aids |
| Heat | Pressure cooker, refrigerator, air conditioner, solar water heater |
| Nuclear Physics | Nuclear power plants, cancer radiotherapy, carbon dating |
| Laser | Barcode scanners, laser surgery, CD/DVD players, laser pointers, fibre optics |
| Electronics & Communication | Mobile phones, computers, television, radio, internet, satellites, radar |
5. Chemistry – Elements, Compounds, Acids, Bases & More
Basic Concepts
- Element: Pure substance made of only one type of atom (e.g., Oxygen, Iron, Gold, Carbon)
- Compound: Substance formed when two or more elements combine chemically (e.g., Water – H₂O, Common Salt – NaCl, Carbon dioxide – CO₂)
- Mixture: Physical combination of substances (e.g., Air, Soil, Sea water)
Acids, Bases and Salts
- Acids: Sour taste, turn blue litmus red (Examples: HCl, H₂SO₄, Acetic acid, Citric acid)
- Bases: Bitter taste, turn red litmus blue (Examples: NaOH, KOH, Ca(OH)₂, Soap, Baking soda)
- Salts: Formed by neutralisation of acid + base (Examples: NaCl, KCl, Baking soda – NaHCO₃)
- pH Scale: 0–7 Acidic | 7 Neutral | 7–14 Basic
Free 20 Marks Test (Unit I): CLICK HERE
Petroleum Products, Fertilizers & Pesticides
- Petroleum Products: Petrol, Diesel, Kerosene, LPG, CNG, Lubricating oil, Plastics, Synthetic rubber
- Fertilizers: Urea, Ammonium sulphate, NPK complex, Super phosphate (provide N, P, K)
- Pesticides: Insecticides, Fungicides, Herbicides, Rodenticides (used to control pests)
6. Life Science (Biology)
Classification of Living Organisms
Five Kingdom Classification (R.H. Whittaker):
- Monera (Bacteria)
- Protista (Amoeba, Algae)
- Fungi (Mushroom, Yeast)
- Plantae (Plants)
- Animalia (Animals)
Evolution & Genetics
- Charles Darwin – Theory of Natural Selection (Survival of the fittest)
- Gregor Mendel – Father of Genetics
- DNA is the genetic material
- Genes are responsible for hereditary characters
Human Diseases & Nutrition
- Communicable Diseases: Tuberculosis, Malaria, Dengue, Typhoid, COVID-19, Cholera
- Non-Communicable Diseases: Diabetes, Hypertension, Cancer, Heart disease, Asthma
- Deficiency Diseases:
- Vitamin A – Night Blindness
- Vitamin B1 – Beriberi
- Vitamin C – Scurvy
- Vitamin D – Rickets
- Iron – Anaemia
- Iodine – Goitre
Free 20 Marks Test (Unit I): CLICK HERE
7. Environment and Ecology
- Ecology: Study of inter-relationship between living organisms and their environment
- Ecosystem: Producers → Primary Consumers → Secondary Consumers → Decomposers
- Biodiversity: Variety of plant and animal life in a particular habitat
- Pollution Types: Air, Water, Soil, Noise, Plastic, Thermal, Radioactive
- Global Warming: Increase in Earth’s temperature due to greenhouse gases (CO₂, Methane, CFCs)
- Ozone Layer Depletion: Caused mainly by Chlorofluorocarbons (CFCs)
- Important Concepts: Sustainable Development, Renewable vs Non-renewable resources, Conservation of Biodiversity
Free 20 Marks Test (Unit I): CLICK HERE
8. Latest Inventions in Science & Technology + Current Affairs
Focus on recent developments in the following areas:
- Space Technology: ISRO missions (Chandrayaan series, Gaganyaan, Aditya-L1, EOS satellites)
- Biotechnology: CRISPR gene editing, mRNA vaccines, GM crops
- Artificial Intelligence & Robotics
- Renewable Energy: Green Hydrogen, Advanced Solar cells, Offshore wind energy
- Medical Science: New vaccines, Artificial organs, Telemedicine
- Communication: 5G / 6G technology, Quantum Communication
- Electric Vehicles & Battery Technology
Tip: Regularly follow The Hindu, PIB, and ISRO website for latest updates.
Download PDF Study Material: CLICK HERE
Quick Revision Tips (For 5 Questions)
- Focus more on everyday applications of scientific principles.
- Learn important deficiency diseases and related vitamins/minerals.
- Revise basic laws (Newton, Ohm, Conservation of Energy).
- Study environmental issues (Global warming, Ozone depletion, Pollution).
- Keep updating latest ISRO missions and major science inventions.
- Practice previous year TNPSC General Science questions regularly.
Free 20 Marks Test (Unit I): CLICK HERE