General Science for Government Exams: Physics, Chemistry, Biology Topics

General Science is the section where non-science background students panic and science graduates become overconfident. Both reactions are wrong. Competitive exam science questions are fundamentally different from your board exam questions — they test applied understanding and general awareness of scientific concepts, not formula-based problem solving.

I have seen arts graduates score 18/20 in SSC CGL science sections and engineering graduates score 8/20, simply because of approach. Here is the strategy that works regardless of your academic background.

Weightage Across Exams

Exam	Questions (approx.)	Marks	Level
SSC CGL Tier-I	7-10	14-20	Class X NCERT level
SSC CHSL	7-10	14-20	Class X NCERT level
SSC MTS	5-8	5-8	Class VIII-X level
Railway NTPC	8-12	16-24	Class X level
Railway Group D	8-10	8-10	Class VIII-X level
UPSC Prelims	5-8	10-16	Applied/Current Science
State PCS	8-15	Varies	Class X-XII level

For SSC and Railway exams, General Science can contribute 15-25% of your total score. Ignoring it means leaving guaranteed marks on the table.

The Three-Subject Breakdown

Physics (30-35% of science questions)

High-frequency topics:

1. Mechanics — Newton's laws (application-based), gravitational force, work-energy-power (basic definitions and units)
2. Light and Optics — Reflection, refraction, lenses, mirrors, human eye defects (myopia, hypermetropia), optical instruments
3. Sound — Speed of sound in different media, echo, ultrasound, SONAR applications
4. Electricity — Ohm's law, resistance, power, household wiring, fuses, earthing, LED vs CFL
5. Magnetism — Magnetic field, electromagnets, electric motor, generator, transformer
6. Heat and Thermodynamics — Conduction, convection, radiation, specific heat, latent heat
7. Modern Physics — Nuclear fission/fusion, radioactivity, X-rays (basic concepts only)
8. Units and Measurements — SI units, derived units, dimensional analysis basics

Source: NCERT Class IX (Ch. 8-12) and Class X (Ch. 10-13) cover 90% of what competitive exams ask from physics.

Chemistry (30-35% of science questions)

High-frequency topics:

1. Acids, Bases, and Salts — pH scale, indicators, common acids and bases, their uses
2. Metals and Non-Metals — Reactivity series, extraction of metals, alloys (brass, bronze, stainless steel, solder)
3. Carbon Compounds — Hydrocarbons, ethanol, ethanoic acid, soaps and detergents
4. Chemical Reactions — Types (combination, decomposition, displacement, redox), balancing equations
5. Periodic Table — Groups, periods, trends, noble gases, halogens, alkali metals
6. Everyday Chemistry — Baking soda vs washing soda, bleaching powder, Plaster of Paris, cement composition
7. Polymers and Plastics — Natural vs synthetic polymers, thermoplastics vs thermosetting
8. Atomic Structure — Protons, neutrons, electrons, isotopes, isobars (basic level)

Source: NCERT Class X (Ch. 1-5) is your primary text. For additional depth, NCERT Class VIII (Ch. 4-6) covers materials and chemical effects well.

Biology (30-35% of science questions)

High-frequency topics:

1. Human Body Systems — Digestive (enzymes, organs), Respiratory (mechanism, gas exchange), Circulatory (heart chambers, blood groups, RBC/WBC), Nervous (brain parts, reflex action), Excretory (kidney function, nephron)
2. Nutrition — Vitamins (sources, deficiency diseases), Minerals, Proteins, Carbohydrates, Fats
3. Diseases — Viral (dengue, COVID, hepatitis), Bacterial (TB, cholera, typhoid), Protozoan (malaria, amoebic dysentery), their vectors and prevention
4. Cell Biology — Cell structure, plant vs animal cell, mitosis vs meiosis (basic)
5. Plant Biology — Photosynthesis, respiration, transpiration, plant hormones
6. Genetics and Evolution — Mendel's laws, DNA structure (basic), heredity, natural selection
7. Ecology — Food chain, food web, ecosystem, biodiversity, conservation
8. Reproduction — Types (sexual, asexual), human reproductive system (basic)

Source: NCERT Class X (Ch. 6-9, 14-16) and Class IX (Ch. 5-7, 13-15). Biology is the most scoring part of General Science because questions are direct and factual.

The Book Strategy

For SSC and Railway (primary):

• NCERT Class IX and X Science textbooks — read them thoroughly, not as a skim
• Lucent's General Science — excellent for revision after NCERTs

For UPSC (supplementary):

• NCERT Class XI-XII Biology (Ch. 1-5, 8, 13-16 of Biology XI; Ch. 8, 13-16 of Biology XII)
• Science Reporter magazine — for current science topics
• NCERT Class XI-XII Chemistry/Physics only for specific topics like nuclear energy, nanotechnology

Do not buy: Expensive science guides marketed for competitive exams. They are bloated rewrites of NCERT content with added confusion.

6-Week Preparation Plan

Week	Subject	Chapters	Source
1	Physics	Mechanics, Light, Sound	NCERT IX Ch. 8-12
2	Physics	Electricity, Magnetism, Heat	NCERT X Ch. 10-13
3	Chemistry	Chemical Reactions, Acids/Bases, Metals	NCERT X Ch. 1-3
4	Chemistry	Carbon, Periodic Table, Everyday Chemistry	NCERT X Ch. 4-5, Lucent
5	Biology	Human Body, Nutrition, Diseases	NCERT X Ch. 6-9, Lucent
6	Biology	Plants, Ecology, Genetics + Full Revision	NCERT X Ch. 14-16, PYQs

Dedicate 1-1.5 hours daily. That is 42-63 hours total — more than enough for exam-level science.

High-Yield Quick Facts

These facts appear year after year. Memorize them:

Physics:

• Speed of light: 3 × 10⁸ m/s
• Speed of sound in air at 20°C: ~343 m/s
• Normal human hearing range: 20 Hz to 20,000 Hz
• Unit of power: Watt; Unit of energy: Joule
• 1 horsepower = 746 watts

Chemistry:

• pH of pure water: 7
• Chemical formula of common salt: NaCl
• Baking soda: NaHCO₃ (Sodium bicarbonate)
• Washing soda: Na₂CO₃·10H₂O
• Bleaching powder: Ca(OCl)Cl
• Plaster of Paris: CaSO₄·½H₂O
• Laughing gas: N₂O (Nitrous oxide)
• Marsh gas: CH₄ (Methane)

Biology:

• Largest organ: Skin
• Largest gland: Liver
• Smallest bone: Stapes (ear)
• Blood groups: A, B, AB, O (Universal donor: O-; Universal recipient: AB+)
• Normal blood pressure: 120/80 mmHg
• Vitamin C deficiency: Scurvy
• Vitamin D deficiency: Rickets (children), Osteomalacia (adults)
• Vitamin B1 deficiency: Beriberi
• Malaria parasite: Plasmodium; Vector: Female Anopheles mosquito

Current Science for UPSC

UPSC science questions have shifted towards applied and current science:

• Space missions: ISRO's Chandrayaan, Gaganyaan, Aditya-L1
• Biotechnology: CRISPR gene editing, mRNA vaccines, GM crops
• Environmental science: Carbon capture, green hydrogen, ozone layer recovery
• Health: New diseases, vaccine developments, antibiotic resistance
• Technology: Quantum computing basics, AI applications, semiconductor manufacturing

For these topics, read the Science & Technology section of any monthly current affairs magazine. Science Reporter (CSIR publication) is particularly good and costs very little. Track exam notifications and science current affairs at sarkarinaukri.in.

How to Handle "Tricky" Science Questions

SSC examiners love statement-based questions: "Which of the following statements is correct?" with 3-4 options. Here is how to handle them:

1. Eliminate obviously wrong statements first. Usually 1-2 options have clear errors.
2. Look for absolute words. Statements with "always," "never," "only" are frequently wrong.
3. Trust NCERT language. If you remember the NCERT phrasing of a concept, it is usually the correct answer.
4. When stuck between two options, go with the one that aligns with basic principles rather than exceptions.

The Vitamin-Disease Table Every Aspirant Needs

Vitamin	Chemical Name	Source	Deficiency Disease
A	Retinol	Carrot, Papaya, Milk	Night blindness
B1	Thiamine	Whole grains, Pork	Beriberi
B2	Riboflavin	Eggs, Milk, Liver	Cheilosis
B3	Niacin	Meat, Peanuts	Pellagra
B6	Pyridoxine	Cereals, Meat	Anaemia
B12	Cobalamin	Meat, Fish, Dairy	Pernicious anaemia
C	Ascorbic acid	Citrus fruits, Amla	Scurvy
D	Calciferol	Sunlight, Fish oil	Rickets
E	Tocopherol	Vegetable oils, Nuts	Sterility
K	Phylloquinone	Green vegetables	Bleeding disorder

Print this table and pin it to your study wall. It has appeared in some form in every SSC exam cycle for the past decade.

General Science is not about deep understanding of advanced concepts. It is about thorough command of Class IX-X level science with the ability to apply that knowledge to everyday situations. Read NCERTs attentively, memorize the high-frequency facts, solve PYQs, and this section will consistently deliver marks for you.