General Science Preparation Guide for Competitive Exams — SSC, Railways, State PSC

General Science is one of those sections where students from a non-science background panic unnecessarily, while science graduates get overconfident and underperform. The truth is that competitive exam science questions are not testing your B.Sc. knowledge — they are testing whether you remember your Class 6-10 NCERT concepts. The questions are straightforward if you have read the right material. This guide from ExamHub will help you build a solid General Science foundation regardless of your academic background.

Where General Science Appears

Exam	Questions (approx.)	Difficulty
SSC CGL (Tier-1)	8-10 in General Awareness	NCERT Class 8-10 level
SSC CHSL	6-8 in General Awareness	NCERT Class 6-10 level
SSC MTS	5-8	Basic, Class 6-8 level
Railways NTPC	10-15 in General Awareness	NCERT Class 8-10 level
Railways Group D	8-10	Basic, Class 6-8 level
State PSC Prelims	10-15	Varies by state, up to Class 12
UPSC Prelims	5-8	Applied science, current science

For SSC and Railways, General Science is essentially free marks if you have done your NCERTs properly. For UPSC, the questions tend to be application-based — testing whether you can apply scientific principles to real-world scenarios.

The NCERT Bible for Science

Here is exactly what to read and in what order:

Class	Focus Areas for Exams
Class 6	Food, fibre, plants, body movements, magnets, electricity basics
Class 7	Nutrition, heat, acids-bases intro, weather, soil, respiration
Class 8	Crop production, microorganisms, metals-nonmetals, cell structure, friction, sound, light
Class 9	Motion, force, gravitation, atoms-molecules, cell biology, diversity, natural resources
Class 10	Chemical reactions, acids-bases-salts, metals, carbon compounds, life processes, electricity, magnetic effects, environment

For SSC/Railways: Class 8-10 NCERTs cover 90% of questions. Read them thoroughly. For State PSC: Add Class 11-12 NCERTs for Biology (especially human physiology and ecology). For UPSC: NCERTs plus current science developments (space missions, health, biotechnology).

Physics — Key Topics and What Gets Asked

Mechanics

1. Newton's Laws of Motion — First law (inertia), Second law (F=ma), Third law (action-reaction). Questions often present real-life scenarios and ask which law applies.
2. Gravitation — Why objects fall, weight vs mass, why astronauts feel weightless. The g value (9.8 m/s2) and how it varies with altitude and depth.
3. Friction — Types (static, sliding, rolling), why we slip on wet floors, why ball bearings reduce friction.
4. Pressure — Why sharp knives cut better (less area, more pressure), hydraulic machines, atmospheric pressure.

Light and Optics

1. Reflection — Laws of reflection, plane mirrors, image characteristics
2. Refraction — Why a stick looks bent in water, lenses (convex and concave), total internal reflection
3. Human eye — How the eye works, defects (myopia, hypermetropia), correction using lenses
4. Dispersion — Why rainbows form, prism experiment

Electricity and Magnetism

1. Current electricity — Ohm's law (V=IR), series vs parallel circuits, household wiring
2. Magnetic effects — Electromagnetic induction, electric motor, generator, transformer
3. Static electricity — Charging by friction, lightning

Sound

1. Speed of sound in different media (solid > liquid > gas)
2. Echo and reverberation
3. Ultrasound and its applications (sonography, SONAR)
4. Human hearing range (20 Hz to 20,000 Hz)

Heat and Thermodynamics

1. Modes of heat transfer — conduction, convection, radiation
2. Specific heat capacity — why water is used in radiators
3. Change of state — melting, boiling, latent heat
4. Thermal expansion — why railway tracks have gaps

Chemistry — Key Topics and What Gets Asked

Acids, Bases, and Salts

Property	Acids	Bases
Taste	Sour	Bitter
pH	Less than 7	More than 7
Litmus	Turns blue litmus red	Turns red litmus blue
Examples	HCl, H2SO4, vinegar, lemon	NaOH, KOH, soap, baking soda

Common questions: pH of blood (7.35-7.45), pH of stomach acid (1.5-3.5), what happens when acid reacts with base (neutralization, forms salt + water).

Metals and Non-Metals

1. Physical properties — malleability, ductility, conductivity, lustre
2. Reactivity series — K, Na, Ca, Mg, Al, Zn, Fe, Ni, Sn, Pb, H, Cu, Hg, Ag, Au, Pt (most reactive to least)
3. Corrosion — rusting of iron (requires both oxygen and moisture), prevention methods (galvanization, painting, oiling)
4. Alloys — brass (Cu+Zn), bronze (Cu+Sn), stainless steel (Fe+Cr+Ni+C), solder (Pb+Sn)

Carbon Compounds

1. Carbon forms four covalent bonds — basis of organic chemistry
2. Hydrocarbons — methane, ethane, propane (saturated) vs ethene, propene (unsaturated)
3. Functional groups — alcohol (-OH), carboxylic acid (-COOH), aldehyde (-CHO)
4. Soaps and detergents — how they work (micelle formation)

Chemical Reactions

1. Types — combination, decomposition, displacement, double displacement, redox
2. Oxidation = loss of electrons, Reduction = gain of electrons (remember OIL RIG)
3. Exothermic vs endothermic reactions
4. Balancing chemical equations — basic skill needed for some SSC questions

Everyday Chemistry

This is a favourite area for examiners:

1. Baking soda (NaHCO3) — used in fire extinguishers, antacids, baking
2. Washing soda (Na2CO3) — water softening, glass manufacturing
3. Plaster of Paris (CaSO4.1/2H2O) — setting broken bones, making toys
4. Bleaching powder (CaOCl2) — water purification, disinfection
5. Common salt (NaCl) — raw material for NaOH, Cl2, Na2CO3

Biology — Key Topics and What Gets Asked

Human Body Systems

System	Key Organs	Function
Digestive	Mouth, stomach, intestines, liver, pancreas	Breaking down food, nutrient absorption
Circulatory	Heart, blood vessels, blood	Transport of oxygen, nutrients, waste
Respiratory	Lungs, trachea, diaphragm	Gas exchange (O2 in, CO2 out)
Nervous	Brain, spinal cord, nerves	Coordination, response to stimuli
Excretory	Kidneys, ureters, bladder	Removal of nitrogenous waste (urea)
Endocrine	Pituitary, thyroid, adrenal, pancreas	Hormone secretion, regulation
Reproductive	Ovaries/testes, uterus	Reproduction, continuation of species

Frequently asked: Blood groups (A, B, AB, O), universal donor (O-), universal recipient (AB+), role of WBCs, RBCs, platelets, hemoglobin.

Diseases

Disease	Caused By	Spread By
Malaria	Plasmodium (protozoa)	Female Anopheles mosquito
Dengue	Dengue virus	Aedes aegypti mosquito
Tuberculosis	Mycobacterium	Air (droplets)
Typhoid	Salmonella typhi	Contaminated water/food
Cholera	Vibrio cholerae	Contaminated water
AIDS	HIV (virus)	Body fluids, blood
Rabies	Rabies virus	Animal bite (usually dog)

Nutrition in Plants and Animals

1. Photosynthesis — 6CO2 + 6H2O + Light -> C6H12O6 + 6O2 (happens in chloroplasts)
2. Modes of nutrition — autotrophic (plants), heterotrophic (animals), saprotrophic (fungi)
3. Vitamins and deficiency diseases — Vitamin A (night blindness), B1 (beriberi), C (scurvy), D (rickets), K (blood clotting issues)

Ecology and Environment

1. Food chain and food web, trophic levels, 10% energy transfer rule
2. Biodegradable vs non-biodegradable waste
3. Ozone layer depletion — CFCs, UV radiation
4. Greenhouse effect and global warming

Best Books for General Science

Book	Best For	Level
NCERT Science (Class 6-10)	All exams — the primary source	Foundation
NCERT Biology (Class 11-12)	State PSC, UPSC	Intermediate
Lucent's General Science	SSC, Railways — quick revision	Basic-Intermediate
General Science (Arihant)	Practice questions, topic-wise	Intermediate
Science and Technology (TMH)	UPSC — current science, applications	Advanced

Preparation Plan (2 Months)

Week	Focus	Activities
1-2	Physics (NCERTs Class 8-10)	Read mechanics, light, sound, electricity chapters. Make formula sheets.
3-4	Chemistry (NCERTs Class 8-10)	Acids-bases, metals, carbon compounds, chemical reactions.
5-6	Biology (NCERTs Class 8-10)	Human body systems, diseases, nutrition, ecology.
7-8	Revision + Mock Tests	Solve PYQs, take topic-wise tests, revise weak areas.

Common Mistakes to Avoid

1. Ignoring science because you are from arts/commerce — The questions are Class 8-10 level. Anyone can learn this in 6-8 weeks with consistent effort.
2. Going too deep — You do not need to know organic chemistry reaction mechanisms or quantum physics. Stick to NCERT-level understanding.
3. Not making a formula/fact sheet — Physics has formulas, Chemistry has reactions and compounds, Biology has diseases and body systems. A 10-page compiled sheet is invaluable for last-minute revision.
4. Skipping diagrams — Biology especially requires you to understand diagrams (human heart, digestive system, nephron). Draw them at least once.
5. Not practicing numerical problems — SSC sometimes asks calculation-based questions in Physics (Ohm's law, speed-distance-time). Use CalcHub to verify your calculations during practice.
6. Reading Class 11-12 for SSC — Overkill. Stick to Class 6-10 for SSC and Railways. Only go higher for State PSC or UPSC.

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