Everyday Science Questions for RRB NTPC

Light and Optics in Daily Life

Light behaves in ways we see every day. Scattering, reflection, refraction, and dispersion all show up in familiar phenomena. The key is knowing which phenomenon causes which effect.

• Sky appears blue because of Rayleigh scattering — short wavelength blue light scatters more in atmosphere.
• Sunset appears red/orange because blue light has scattered away, leaving longer red wavelengths.
• Rainbow is caused by dispersion of sunlight through water droplets — VIBGYOR order.
• Mirage is caused by total internal reflection of light in hot air near the ground.
• A swimming pool appears shallower than it is due to refraction of light.
• Optical fibre works on the principle of total internal reflection.

Sound and Heat in Everyday Life

Sound is a mechanical wave and behaves predictably in daily environments. Heat transfer explains why we feel warm or cold and how cooking and cooling devices work.

• Sound travels faster in solids than in liquids than in gases — remember Solid beats Liquid beats Gas (SLG fastest to slowest).
• Echo requires a minimum distance of about 17 metres from a reflecting wall.
• Pressure cooker cooks food faster because increased pressure raises the boiling point of water.
• Refrigerator works on evaporation — refrigerant absorbs heat when it evaporates, cooling the inside.
• Thermos flask prevents heat transfer by vacuum (no conduction or convection) and silvered walls (no radiation).
• Woollen clothes keep us warm by trapping air, which is a poor conductor of heat.

Common Chemistry Phenomena

Chemistry is at work when food gets spoiled, metals rust, soaps clean, and baking soda fizzes. RRB NTPC frequently tests the why behind these events.

• Rusting of iron requires both water and oxygen — remove either one to prevent rust (hence painting, oiling).
• Soap works by having one end that attracts water (hydrophilic) and one that attracts oil (hydrophobic) — it is an emulsifier.
• Baking soda (NaHCO3) releases CO2 when heated or mixed with acid — this makes cakes fluffy.
• Salt lowers the freezing point of water (freezing point depression) — that is why it melts ice on roads.
• Milk turns sour because bacteria convert lactose into lactic acid.
• Antacids like ENO contain sodium bicarbonate which neutralises excess stomach acid.

Human Body and Health

The human body uses science at every step — digestion, immunity, vision, and circulation. Questions here are often direct and factual.

• Deficiency of Vitamin C causes Scurvy; Vitamin D causes Rickets; Vitamin A causes Night Blindness.
• Insulin is secreted by the pancreas and regulates blood sugar — its deficiency causes Diabetes.
• Vaccines create immunity by introducing a weakened or dead form of a pathogen so the body learns to fight it.
• Blood group O is universal donor; AB is universal recipient.
• The human eye uses a convex lens to focus light — near-sightedness is corrected by concave lens, far-sightedness by convex lens.
• Haemoglobin in red blood cells carries oxygen; its deficiency leads to Anaemia.

Machines and Gadgets

Everyday appliances are tested in RRB NTPC to check if you understand the science behind them. Focus on the working principle, not the engineering details.

• Electric bulb (filament type) works on the heating effect of electric current — tungsten filament glows white hot.
• CFL and LED bulbs are more energy efficient than filament bulbs.
• Microwave oven heats food by causing water molecules to vibrate rapidly using microwave radiation.
• Transformer works on electromagnetic induction — step-up increases voltage, step-down decreases it.
• A simple battery converts chemical energy into electrical energy.
• Hydraulic brakes work on Pascal's Law — pressure applied at one point is transmitted equally in all directions in a fluid.

Environment and Atmosphere

Basic environmental science is part of everyday science in exams. Greenhouse effect, ozone layer, acid rain — these are asked directly.

• Greenhouse gases (CO2, methane, water vapour) trap heat in the atmosphere causing global warming.
• Ozone layer in the stratosphere protects Earth from harmful UV radiation — depleted by CFCs.
• Acid rain is caused by SO2 and NO2 mixing with rainwater to form sulphuric and nitric acids.
• Photosynthesis: Plants use sunlight, water, and CO2 to produce glucose and oxygen.
• Decomposition by bacteria and fungi recycles nutrients back into the soil.

• Confusing the cause of rainbow (dispersion) with the cause of blue sky (scattering) — they are completely different phenomena.
• Mixing up universal blood donor (O) with universal recipient (AB) — many aspirants get this reversed under exam pressure.
• Assuming sound travels fastest in air — it actually travels fastest in solids. Air is the slowest medium among solids, liquids, and gases.
• Saying a refrigerator produces cold — it actually removes heat from inside. The compressor and refrigerant absorb and expel heat outside.
• Confusing concave and convex lens corrections — near-sighted (myopia) needs concave, far-sighted (hypermetropia) needs convex.

• VIBGYOR for rainbow colours: Violet Indigo Blue Green Yellow Orange Red — Violet bends most, Red bends least.
• For vitamins and deficiencies use ABCD: A for blind At night, B for Beriberi, C for Cuts that bleed (Scurvy), D for Deformed bones (Rickets).
• Blood groups memory: O is the Only one that gives to all (universal donor), AB Accepts Blood from anyone (universal recipient).
• SLG for sound speed: Sound travels fastest in Solids, then Liquids, then Gas — think of SLG as Solid Leads Generally.
• Rusting needs BOTH water AND oxygen — remember RWO: Rust Wants Oxygen and water.

• RRB NTPC has asked direct factual questions like which gas is responsible for acid rain, which vitamin prevents night blindness, and what principle does a hydraulic brake use — prepare a quick mental checklist of phenomena and their scientific reasons.
• Everyday Science questions in recent papers (2019, 2021, 2024) frequently appear in sets — one question on light phenomena, one on the human body, one on common chemistry. So prepare all sub-areas, not just one.
• These questions are low difficulty — aim to attempt all of them within 30 to 45 seconds each. Do not overthink; first instinct based on revision is usually correct.
• Watch out for distractors that mix two correct-sounding options — for example, both CO2 and methane are greenhouse gases, but the examiner may ask which one is most responsible for global warming (answer: CO2 in overall contribution).
• For GA plus Science combined sections in CBT-1, Everyday Science often overlaps with questions tagged under Current Affairs and Environment — knowing causes of pollution, greenhouse effect, and ozone depletion gives you double benefit.