TNPSC Group IV · Bite-size lessons
General Science
About 6 min · General Studies (SSLC standard) · English
Time worked out from the lesson's 399 words at 150 words a minute, plus a minute for each question.
General Science is Unit I of the General Studies part of the TNPSC Group IV examination (5 questions in the official syllabus), testing candidates on fundamental scientific concepts at the SSLC (10th standard) level. This section covers Physics, Chemistry, Botany, and Zoology — essentially the core science you studied in school but now applied to competitive exam formats.
Key ideas
- Matter exists in three states — solid, liquid, and gas — with distinct properties of shape, volume, and compressibility. Plasma is the fourth state found in stars and fluorescent tubes.
- Newton's three laws of motion explain all mechanical phenomena: inertia (objects resist change), F = ma (force produces acceleration), and action-reaction pairs.
- Energy can neither be created nor destroyed, only transformed from one form to another — this Law of Conservation of Energy governs all physical and chemical processes.
- Atoms combine through ionic or covalent bonding — ionic involves electron transfer (NaCl), covalent involves electron sharing (H₂O).
- Photosynthesis is the foundation of life on Earth — plants convert CO₂ and water into glucose and oxygen using sunlight and chlorophyll.
Watch out for
- Confusing speed with velocity → Speed is scalar (magnitude only), velocity is vector (magnitude + direction). A car going in circles has speed but zero average velocity.
- Mixing up atomic number and mass number → Atomic number is protons only (identifies the element); mass number is protons plus neutrons.
- Believing plants only respire at night → Plants respire 24 hours; photosynthesis occurs only in light. During day, photosynthesis rate exceeds respiration rate.
Quick reference
- SI unit of force: Newton (N); SI unit of energy: Joule (J)
- Vitamin deficiencies: A = Night blindness; B₁ = Beriberi; C = Scurvy; D = Rickets; K = Bleeding disorders
- Blood groups: A, B, AB (universal recipient), O (universal donor)
- Largest organ: Skin; Largest gland: Liver; Largest cell: Ovum (egg cell)
- Good conductors: Metals (silver best); Insulators: Rubber, plastic, wood, glass
Check yourself: 3 questions
1. A ball is dropped from a height of 20 metres. Assuming no air resistance, which form of energy does the ball possess just before it hits the ground?
2. Which of the following is a chemical change?
3. The process by which plants lose water in the form of water vapour through stomata is called:
This lesson is cut from the topic's note, not rewritten. Fact-checked on 17 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.
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