Everyday Science: High-Yield Facts
Minerals & Their Deficiency Diseases
Alongside vitamins, the body needs certain minerals in small quantities. Their deficiency diseases are just as frequently asked, and the paper likes to mix vitamin and mineral deficiencies in the same statement question to test careful reading.
| Mineral | Deficiency effect |
|---|---|
| Iron | Anaemia (low haemoglobin) |
| Iodine | Goitre (swollen thyroid); cretinism in children |
| Calcium | Weak bones and teeth; muscle cramps |
| Zinc | Stunted growth; delayed wound healing |
| Fluorine | Deficiency → tooth decay; excess → fluorosis (mottled teeth, bone damage) |
Chemistry in the Kitchen
| Everyday name | Chemical name & formula |
|---|---|
| Common salt | Sodium chloride — NaCl |
| Baking soda | Sodium bicarbonate — NaHCO₃ |
| Washing soda | Sodium carbonate — Na₂CO₃ |
| Lime / quicklime | Calcium oxide — CaO |
| Chalk / marble | Calcium carbonate — CaCO₃ |
Physics You Can Feel
- Light travels at about 3 × 10⁸ metres per second — the fastest thing in the universe. That is why we see lightning before we hear thunder.
- Sound needs a medium (air, water, solid) to travel — it cannot travel through a vacuum. It travels faster in solids than in air.
- SI units: length = metre, mass = kilogram, time = second, temperature = kelvin, electric current = ampere.
- Newton's first law (inertia): an object stays at rest or keeps moving unless a force acts on it — this is why you lurch forward when a bus suddenly stops.
Two more everyday-physics topics come up often: the electromagnetic spectrum and mirrors/lenses.
- The electromagnetic spectrum, in order of increasing frequency (decreasing wavelength): Radio waves → Microwaves → Infrared → Visible light → Ultraviolet → X-rays → Gamma rays. Radio waves have the longest wavelength; gamma rays have the highest energy.
- Concave mirrors (curve inward) converge light and are used in shaving/makeup mirrors, headlights and torches; convex mirrors (curve outward) diverge light, giving a wider field of view, and are used as vehicle side/rear-view mirrors.
- Convex lenses (thicker in the middle) converge light and correct long-sightedness (hypermetropia); concave lenses (thinner in the middle) diverge light and correct short-sightedness (myopia).
Key takeaways
- Vitamins: A → night blindness, B1 → beri-beri, C → scurvy, D → rickets, K → poor clotting. D = sunshine vitamin.
- Salt = NaCl; baking soda = NaHCO₃; washing soda = Na₂CO₃; chalk/marble = CaCO₃.
- pH: below 7 = acidic, 7 = neutral, above 7 = basic. Acid reddens blue litmus; base blues red litmus.
- Light ≈ 3 × 10⁸ m/s; sound needs a medium (no sound in vacuum), faster in solids.
- Units: force → newton, work/energy → joule, power → watt. Newton's 1st law = inertia.
- Minerals: Iron → anaemia, Iodine → goitre, Calcium → weak bones, Zinc → stunted growth, Fluorine deficiency → tooth decay (but excess → fluorosis).
- EM spectrum (increasing frequency): Radio → Microwave → Infrared → Visible → Ultraviolet → X-ray → Gamma. Concave mirror/lens = converges/diverges light differently; convex lens corrects hypermetropia, concave lens corrects myopia.
Practice questions (12)
Attempt each one before opening the answer. Every explanation names the tempting wrong option as well as the right one, because that is where marks are lost.
Deficiency of which vitamin causes night blindness?
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Answer: A — Vitamin A
Deficiency of Vitamin A (Retinol) causes night blindness.Scurvy is caused by the deficiency of:
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Answer: C — Vitamin C
Scurvy is caused by a deficiency of Vitamin C (Ascorbic acid), found in citrus fruits like lemon and orange.The chemical name of common salt is:
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Answer: B — Sodium chloride
Common salt is sodium chloride (NaCl). Sodium bicarbonate is baking soda; sodium carbonate is washing soda.What is the pH value of a neutral solution like pure water?
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Answer: B — 7
Pure water is neutral with a pH of 7. Below 7 is acidic and above 7 is basic (alkaline).The SI unit of force is the:
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Answer: C — Newton
The SI unit of force is the newton (N). The joule is the unit of energy/work and the watt is the unit of power.Consider the following statements:
1. Sound can travel through a vacuum.
2. Light travels faster than sound.
Which is/are correct?Show answer
Answer: B — Only 2
Statement 1 is wrong — sound needs a medium and cannot travel through a vacuum. Statement 2 is correct — light is much faster than sound.Which disease is caused by the deficiency of Vitamin D in children?
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Answer: B — Rickets
Vitamin D deficiency causes rickets in children (and osteomalacia in adults). Vitamin D is called the sunshine vitamin.The chemical formula NaHCO₃ represents:
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Answer: B — Baking soda
NaHCO₃ is sodium bicarbonate, commonly known as baking soda.Deficiency of which mineral causes goitre (swelling of the thyroid gland)?
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Answer: B — Iodine
Iodine deficiency causes goitre and, in children, cretinism. Iron deficiency causes anaemia.Consider the following statements about fluorine:
1. Deficiency of fluorine can cause tooth decay.
2. Excess fluorine in drinking water can cause fluorosis.
Which is/are correct?Show answer
Answer: C — Both 1 and 2
Both are correct — fluorine deficiency causes tooth decay, while excess fluorine (common in groundwater in some regions) causes fluorosis, damaging teeth and bones.In the electromagnetic spectrum, which of the following has the highest frequency (and highest energy)?
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Answer: D — Gamma rays
Gamma rays have the highest frequency and energy in the electromagnetic spectrum; radio waves have the lowest frequency and longest wavelength.Which type of lens is used to correct short-sightedness (myopia)?
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Answer: B — Concave lens
A concave lens (thinner in the middle) diverges light and corrects myopia (short-sightedness); a convex lens corrects hypermetropia (long-sightedness).