Basic Science

Why basic science matters in AFCAT

The General Awareness section blends static knowledge with current affairs, and basic science is one of its steadiest static pillars. Every AFCAT shift carries a few science questions, and they are almost always direct, single-fact items — the SI unit of force, the gas that turns lime water milky, the disease caused by a vitamin deficiency. There is no derivation and no numerical work.

That makes basic science a high-return area for a focused candidate. The examinable core comes straight from NCERT Class 6–10 science with a few Class 11–12 highlights, so the syllabus is finite and the same facts recur across shifts. A few hours spent organising these facts into clusters converts most science questions into certain marks — valuable under AFCAT's negative marking, where every confident attempt protects your score.

How to organise the topic

Trying to re-read entire science textbooks is the slow path. The smart approach is to extract the few hundred facts AFCAT actually tests and arrange them into fixed tables you revise in rotation.

• Physics: quantities and their SI units, laws stated in words, everyday applications.
• Chemistry: element symbols, common compounds and their uses, acid–base basics, types of reactions.
• Biology: human body systems, vitamins and deficiency diseases, plant processes, cell basics.

Storing facts as clusters means each item reinforces a structure rather than floating alone. When AFCAT tests any member of a cluster — say one SI unit — the rest of the table is primed in your memory, which both speeds recall and helps you spot the odd one out in matching questions.

Physics: quantities and SI units

The most common physics question simply asks the SI unit of a quantity, or names the quantity for a given unit. Fix this table once.

• Force — newton (N)
• Work / Energy — joule (J)
• Power — watt (W)
• Pressure — pascal (Pa)
• Frequency — hertz (Hz)
• Electric current — ampere (A)
• Electric charge — coulomb (C)
• Potential difference — volt (V)
• Resistance — ohm (Ω)
• Temperature — kelvin (K)

Several units are named after scientists, which is itself a question type — force after Newton, pressure after Pascal, current after Ampère. Learn the unit and the person together and you cover two question patterns at once.

Physics: laws and everyday applications

AFCAT states physics laws in plain language and asks you to name them, or links a phenomenon to its principle. Know the headline laws and one application each.

• Newton's first law (inertia): a body stays at rest or in uniform motion unless a force acts — why passengers lurch when a bus brakes.
• Newton's third law: every action has an equal and opposite reaction — the principle behind rocket and jet propulsion.
• Archimedes' principle: an immersed body is buoyed up by a force equal to the weight of fluid displaced — why ships and balloons float.
• Pascal's law: pressure applied to a confined fluid is transmitted equally — the basis of hydraulic brakes and lifts.
• Ohm's law: current is proportional to voltage for a constant resistance.
• Reflection and refraction of light: a mirror reflects; a lens or prism bends light, explaining rainbows and why a straw looks bent in water.

Chemistry: elements and symbols

Symbol questions are frequent and easy marks. Most symbols are obvious from the English name, but a set comes from Latin and trips up unprepared candidates.

• Sodium — Na (from natrium)
• Potassium — K (from kalium)
• Iron — Fe (from ferrum)
• Gold — Au (from aurum)
• Silver — Ag (from argentum)
• Lead — Pb (from plumbum)
• Tin — Sn (from stannum)
• Mercury — Hg (from hydrargyrum)
• Copper — Cu (from cuprum)

Group the “Latin nine” above and drill them separately, since they cause nearly all symbol errors. The remaining common elements — H, O, C, N, Ca, Mg, Cl, S — follow their English names and need little effort.

Chemistry: common compounds and reactions

AFCAT tests everyday compounds by formula, common name or use, and a few named reactions or gas tests. Keep a compact table of household and lab chemistry.

• Water — H₂O; Carbon dioxide — CO₂; Ammonia — NH₃.
• Common salt — sodium chloride, NaCl; Baking soda — sodium bicarbonate, NaHCO₃.
• Washing soda — sodium carbonate; Quick lime — calcium oxide, CaO; Slaked lime — calcium hydroxide.
• Blue vitriol — copper sulphate; Plaster of Paris — calcium sulphate hemihydrate.

Two reaction facts are favourites: carbon dioxide turns lime water milky, a standard test for the gas, and acids turn blue litmus red while bases turn red litmus blue. Know also that an acid plus a base gives a salt and water (neutralisation), and that rusting of iron is slow oxidation needing both air and moisture.

Biology: vitamins and deficiency diseases

The vitamin–disease table is one of the single most tested science clusters in competitive exams. Learn each vitamin's chemical name, its source role and the disease its deficiency causes.

• Vitamin A (retinol) — deficiency causes night blindness; supports vision.
• Vitamin B1 (thiamine) — deficiency causes beriberi.
• Vitamin B12 — deficiency causes anaemia.
• Vitamin C (ascorbic acid) — deficiency causes scurvy; aids immunity.
• Vitamin D — deficiency causes rickets in children and weak bones in adults; made in skin with sunlight.
• Vitamin K — needed for blood clotting.

Remember which vitamins are fat-soluble (A, D, E, K) and which are water-soluble (B-group and C), as that distinction also appears. The deficiency-disease links — especially scurvy (C), beriberi (B1), rickets (D) and night blindness (A) — are near-certain to feature in some shift.

Biology: human body and life processes

Questions on the human body and basic life processes are common and straightforward. Cover the headline facts for each system.

• Cell — the basic structural and functional unit of life; the mitochondrion is the “powerhouse” producing energy.
• Blood — carries oxygen via haemoglobin in red cells; the heart has four chambers (two atria, two ventricles).
• Respiration — we breathe in oxygen and breathe out carbon dioxide; the lungs are the main organ.
• Digestion — the liver is the largest gland; bile aids fat digestion; the small intestine absorbs nutrients.
• Bones — an adult human body has 206 bones; the skeleton supports and protects organs.

For plants, two processes recur: photosynthesis, in which green plants use sunlight, carbon dioxide and water to make food and release oxygen, and transpiration, the loss of water vapour from leaves. Chlorophyll, the green pigment, traps the sunlight that drives photosynthesis.

Worked example: an SI unit question

Worked example: a vitamin question

An NCERT-first revision plan and exam-day approach

The safest single rule for AFCAT basic science is to stay close to NCERT. The exam draws its facts from the standard Class 6–10 science syllabus, with a thin layer of Class 11–12 highlights, and it pitches questions at definition-and-fact level rather than at advanced theory.

So your reading should be selective. Skim the NCERT chapters for the boxed definitions, named laws, labelled diagrams and summary points, and copy only those into your three subject sheets. You do not need to master derivations, long mechanisms or numerical problem-solving, because AFCAT does not test them in this section. The aim is breadth of clean facts, not depth in any one topic.

This selective method also keeps revision light. A candidate who has distilled NCERT into three sheets can re-read the whole of basic science in under an hour, which means several full revisions are possible in the final fortnight before the exam — exactly the repetition that fixes facts for recall.

With that foundation in place, basic science rewards organised, repeated revision over heavy reading. Here is a Cavalier-tested routine.

1. Build three subject sheets — physics, chemistry, biology — from NCERT definitions, laws, units and key tables.
2. Revise them in short spaced sessions, rotating subjects so each is seen several times a week.
3. Drill the high-trap clusters — Latin symbols, SI units, vitamin–disease pairs — as separate flashcards.
4. Solve previous-year and mock questions to learn which facts AFCAT repeats most.
5. In the exam, treat science as quick, confident marks; if a fact is genuinely unknown, use clustering to eliminate before deciding whether to attempt.

Previous-year style practice

Try this AFCAT-pattern question, then check the reasoning.