General Science is 25 questions in RRB Group D and 20 in RRB ALP CBT-1 - and almost every question is a one-line NCERT Class 9–10 fact. This page compresses the highest-frequency facts into three revision tables. Read one table per sitting, then immediately attempt the matching Science practice set - recall within an hour of reading doubles retention.
| Question / fact | Answer |
|---|---|
| SI unit of force | newton (N); 1 N = 1 kg·m/s² |
| SI unit of work and energy | joule (J) |
| SI unit of power | watt (W); 1 hp ≈ 746 W |
| SI unit of pressure | pascal (Pa) |
| SI unit of frequency | hertz (Hz) |
| SI unit of electric current | ampere (A) |
| Speed of light in vacuum | 3 × 10⁸ m/s |
| Speed of sound in air (approx.) | ≈ 343 m/s at 20°C; fastest in solids, slowest in gases |
| Newton's first law | Law of inertia |
| Newton's third law | Every action has an equal and opposite reaction |
| Acceleration due to gravity (g) | ≈ 9.8 m/s²; maximum at poles, minimum at equator |
| Mass vs weight | Mass is constant everywhere; weight = mg, changes with g |
| Device to measure current | Ammeter (connected in series) |
| Device to measure potential difference | Voltmeter (connected in parallel) |
| Ohm's law | V = IR |
| Commercial unit of electrical energy | kilowatt-hour (kWh) = 1 'unit' = 3.6 × 10⁶ J |
| A fuse wire has | High resistance and low melting point |
| Image in a plane mirror | Virtual, erect, laterally inverted, same size |
| Mirror used as a rear-view mirror | Convex mirror (wider field of view) |
| Mirror used by dentists | Concave mirror |
| Lens used to correct myopia | Concave lens; hypermetropia → convex lens |
| Splitting of white light by a prism | Dispersion; violet bends most, red least |
| The sky appears blue due to | Scattering of light (Rayleigh scattering) |
| Sound cannot travel through | Vacuum |
| Frequency range of human hearing | 20 Hz to 20,000 Hz |
| Waves used by bats and in SONAR | Ultrasonic waves (above 20,000 Hz) |
| Question / fact | Answer |
|---|---|
| Smallest particle of an element | Atom; smallest particle of a compound that exists freely - molecule |
| Proton discovered by / electron discovered by | Goldstein (proton, canal rays); J. J. Thomson (electron) |
| Neutron discovered by | James Chadwick (1932) |
| Atomic number = | Number of protons; Mass number = protons + neutrons |
| Isotopes | Same atomic number, different mass number (e.g. H-1, H-2, H-3) |
| Modern periodic law given by | Henry Moseley - properties are a periodic function of atomic number |
| Most abundant element in Earth's crust | Oxygen, followed by silicon; most abundant metal - aluminium |
| Most abundant gas in the atmosphere | Nitrogen (~78%) |
| pH of pure water / human blood | 7 (neutral) / ≈ 7.4 (slightly basic) |
| Acid in lemon / vinegar / ant sting | Citric acid / acetic acid / formic (methanoic) acid |
| Common salt / baking soda / washing soda | NaCl / NaHCO₃ / Na₂CO₃·10H₂O |
| Plaster of Paris formula | CaSO₄·½H₂O (calcium sulphate hemihydrate) |
| Chemical name of bleaching powder | Calcium oxychloride, CaOCl₂ |
| Hardest natural substance | Diamond (an allotrope of carbon) |
| Liquid metal at room temperature | Mercury; liquid non-metal - bromine |
| Metal that floats on water | Sodium and potassium (stored in kerosene) |
| Rusting of iron requires | Both oxygen and moisture; prevention - galvanisation (zinc coating) |
| Brass is an alloy of | Copper + zinc; Bronze - copper + tin; Steel - iron + carbon |
| Gas released when acids react with metals | Hydrogen (burns with a pop sound) |
| Dry ice is | Solid carbon dioxide (CO₂) |
| LPG mainly contains / CNG mainly contains | Butane (with propane) / methane |
| Gas used in electric bulbs | Argon (inert gas); in tube lights - mercury vapour + argon |
| Question / fact | Answer |
|---|---|
| Basic structural and functional unit of life | Cell (discovered by Robert Hooke, 1665) |
| Powerhouse of the cell | Mitochondria; kitchen of the cell - chloroplast |
| Cell organelle called 'suicide bag' | Lysosome |
| Site of photosynthesis and its equation | Chloroplast; 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ (in sunlight, chlorophyll) |
| Largest organ / largest gland of human body | Skin / liver |
| Largest and smallest bone | Femur (thigh) / stapes (middle ear) |
| Number of bones in adult human body | 206 (306 at birth); muscles - over 600 |
| Normal human blood pressure / heartbeat | 120/80 mm Hg / 72 beats per minute (resting) |
| Universal donor / universal recipient blood group | O negative / AB positive |
| Blood component that helps clotting | Platelets (thrombocytes) |
| Oxygen carrier in blood | Haemoglobin (contains iron) |
| Master gland of human body | Pituitary gland |
| Insulin is produced by | Beta cells of islets of Langerhans in the pancreas; deficiency - diabetes mellitus |
| Vitamin C deficiency causes / Vitamin D deficiency causes | Scurvy / rickets (children), osteomalacia (adults) |
| Vitamin A deficiency / Vitamin B12 deficiency | Night blindness / pernicious anaemia |
| Vitamin synthesised by skin in sunlight | Vitamin D |
| Iodine deficiency causes | Goitre (thyroid enlargement) |
| Exchange of gases in lungs occurs at | Alveoli |
| Functional unit of kidney | Nephron |
| Diseases caused by viruses | Common cold, influenza, dengue, rabies, polio, COVID-19, AIDS |
| Diseases caused by bacteria | Tuberculosis, typhoid, cholera, tetanus, leprosy |
| Diseases caused by protozoa | Malaria (Plasmodium, female Anopheles), amoebiasis, kala-azar |
| Father of genetics | Gregor Mendel (worked on pea plants) |
| DNA double helix model given by | Watson and Crick (1953) |
These ~70 facts cover the most repeated one-mark science questions in Railway exams, but they are anchors, not the whole syllabus - each row should remind you of the NCERT chapter behind it. The working method: read a table, close it, and write whatever you remember on paper; whatever you missed goes into your error notebook. After two passes, move to timed practice sets and let the wrong answers tell you which chapter to reopen. Science rewards exactly this loop - facts in, recall out, gaps patched.
25 questions (out of 100) in the CBT - General Science at Class 9–10 NCERT level covering physics, chemistry and life sciences. In RRB ALP CBT-1 it is 20 questions.
Yes - Class 9 and 10 NCERT Science covers the syllabus boundary for Group D and ALP CBT-1. Supplement with one-liner revision and timed practice sets; you do not need higher-level books.
Units and measurements, laws of motion, electricity basics, light and sound, acids-bases-salts, metals and alloys, the human body (blood, bones, glands, vitamins), and diseases with their causal organisms.