General Science questions in RSMSSB LDC, SSC CHSL, and most state-level government exams draw heavily from NCERT Class 10 Science — particularly from electricity, optics, acids/bases, metals, and basic biology. Candidates who treat Class 10 Science as a separate subject tend to over-study it; those who focus on the chapters examiners actually draw from score faster and more reliably.
How NCERT Class 10 Science Maps to Government Exams
NCERT Class 10 Science has 16 chapters across Physics, Chemistry, and Biology. Not all chapters are equally tested. Examiners tend to pick from:
| Subject | High-frequency chapters | Rarely tested |
|---|---|---|
| Physics | Electricity, Magnetic Effects, Light (reflection/refraction), Human Eye | Sources of Energy |
| Chemistry | Acids/Bases/Salts, Metals and Non-metals, Periodic Table, Chemical Reactions | Carbon Compounds (mostly SSC, not LDC) |
| Biology | Life Processes, Our Environment, Heredity | Reproduction (occasionally) |
Practice with chapter-level filtering at MedhaV NCERT Class 10 — select Science and pick the chapters you want to drill.
Physics — What to Know
Electricity (Chapter 12)
The most frequently tested physics chapter across all competitive exams.
Key formulas:
- Ohm's Law: V = I × R (Voltage = Current × Resistance)
- Power: P = V × I = I² × R
- Resistors in series: R_total = R1 + R2 + R3
- Resistors in parallel: 1/R_total = 1/R1 + 1/R2 + 1/R3
Exam questions test: which gives more current in parallel or series, what happens to resistance when wire length/thickness changes, SI units (Volt, Ampere, Ohm, Watt).
Magnetic Effects of Current (Chapter 13)
- Fleming's Left-Hand Rule: thumb = motion, index = field, middle = current (for motors)
- Fleming's Right-Hand Rule: for generators (current direction)
- AC vs DC: AC changes direction; household supply is AC at 50 Hz in India
- Electromagnet vs permanent magnet: electromagnet can be switched off
Light — Reflection and Refraction (Chapter 10)
- Concave mirror: converging; used in torches, headlights, solar cookers
- Convex mirror: diverging; used as rear-view mirrors (gives wider field)
- Concave lens: diverging; corrects myopia (short-sightedness)
- Convex lens: converging; corrects hypermetropia (long-sightedness)
- Snell's Law: n1 sin θ1 = n2 sin θ2
- Refractive index of glass is higher than air — light slows down and bends
Human Eye and Colourful World (Chapter 11)
- Myopia (near-sightedness): image forms in front of retina; corrected by concave lens
- Hypermetropia (far-sightedness): image forms behind retina; corrected by convex lens
- Presbyopia: age-related loss of near focus; corrected by bifocals
- Splitting of white light by a prism: VIBGYOR (Violet bends most, Red bends least)
- Rainbow: same dispersion as a prism; secondary rainbow has reversed colours
Chemistry — What to Know
Acids, Bases and Salts (Chapter 2)
pH scale (0–14):
- pH below 7 = acidic; pH 7 = neutral; pH above 7 = basic/alkaline
- Stomach acid (HCl): pH ~1–2; pure water: pH 7; baking soda: pH ~9
Common chemicals and their names:
| Chemical formula | Common name |
|---|---|
| NaCl | Common salt (table salt) |
| NaOH | Caustic soda (sodium hydroxide) |
| Ca(OH)2 | Slaked lime |
| CaO | Quick lime |
| Na2CO3 | Washing soda |
| NaHCO3 | Baking soda |
| H2SO4 | Sulphuric acid (oil of vitriol) |
| HCl | Hydrochloric acid (muriatic acid) |
| HNO3 | Nitric acid |
| CH3COOH | Acetic acid (vinegar) |
Indicators: Litmus (red in acid, blue in base); Phenolphthalein (pink in base, colourless in acid).
Metals and Non-metals (Chapter 3)
Reactivity series (most reactive → least reactive): K > Na > Ca > Mg > Al > Zn > Fe > Pb > (H) > Cu > Ag > Au > Pt
Key facts:
- Metals above hydrogen in the reactivity series displace H2 from dilute acids
- Gold and platinum do not react with dilute acids or oxygen — hence used in jewellery
- Aluminium is protected by oxide layer; iron rusts (iron oxide)
- Corrosion (rusting) requires both oxygen and water
Periodic Classification (Chapter 5)
- Modern Periodic Table: 18 groups, 7 periods
- Mendeleev's table arranged elements by atomic mass; Modern Periodic Table by atomic number
- Period 1: H, He (2 elements); Period 2: Li to Ne (8 elements); Period 3: Na to Ar (8 elements)
- Groups 1–2: metals (alkali metals, alkaline earth metals); Groups 17–18: non-metals (halogens, noble gases)
- Noble gases (Group 18): He, Ne, Ar, Kr, Xe, Rn — chemically inert, complete outer shell
Chemical Reactions (Chapter 1)
Types of reactions with examples:
- Combination: A + B → AB (e.g., 2H2 + O2 → 2H2O)
- Decomposition: AB → A + B (e.g., 2H2O → 2H2 + O2 via electrolysis)
- Displacement: A + BC → AC + B (more reactive displaces less reactive)
- Double displacement: AB + CD → AD + CB (precipitation reactions)
- Oxidation: gain of oxygen or loss of hydrogen
- Reduction: loss of oxygen or gain of hydrogen
Biology — What to Know
Life Processes (Chapter 6)
- Photosynthesis: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2 (in chloroplasts)
- Respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (in mitochondria — "powerhouse of cell")
- Aerobic respiration: with oxygen; produces 38 ATP; complete oxidation
- Anaerobic respiration: without oxygen; produces lactic acid (muscles) or ethanol (yeast)
- Human digestive system: mouth → oesophagus → stomach → small intestine → large intestine → rectum
- Digestive enzymes: salivary amylase (starch), pepsin (proteins in stomach), lipase (fats)
Our Environment (Chapter 15)
- Food chain: Producers (plants) → Herbivores → Carnivores → Decomposers
- Trophic level: each step in a food chain; energy transferred is ~10% (90% lost as heat)
- Ozone layer: present in stratosphere; depleted by CFCs (chlorofluorocarbons)
- Ozone (O3) absorbs harmful UV radiation
- Biodegradable: broken down by micro-organisms (paper, food waste)
- Non-biodegradable: not broken down (plastics, metals, DDT)
Heredity and Evolution (Chapter 9)
- Mendel's First Law (Law of Segregation): two alleles for each trait separate during gamete formation
- Mendel's Second Law (Independent Assortment): genes for different traits assort independently
- Dominant vs Recessive: dominant trait expressed even with one copy; recessive needs two copies
- Evolution: gradual change in heritable characteristics; natural selection (Darwin)
- Fossils: preserved remains of past organisms; evidence for evolution
Quick Reference — High-Frequency Exam Facts
| Fact | Answer |
|---|---|
| Unit of resistance | Ohm (Ω) |
| Unit of electric current | Ampere (A) |
| Mirror used in car headlights | Concave mirror |
| Mirror used as rear-view | Convex mirror |
| Lens for myopia correction | Concave lens |
| pH of pure water | 7 |
| Powerhouse of the cell | Mitochondria |
| Site of photosynthesis | Chloroplast |
| Ohm's Law | V = IR |
| Most reactive metal | Potassium (K) |
| Least reactive metal | Platinum (Pt) |
| Groups in Modern Periodic Table | 18 |
| Periods in Modern Periodic Table | 7 |
| Ozone depleted by | CFCs |
| Energy transfer per trophic level | ~10% |
Practice NCERT Class 10 Science MCQs — chapter-by-chapter, bilingual, with explanation.
→ Start NCERT Class 10 Science Practice on MedhaV.in