Explanation

• Almost all the mass of an atom is concentrated in its nucleus.
• The nucleus contains protons and neutrons, which are much heavier than electrons.
• Electrons revolve around the nucleus but contribute very little to atomic mass.
• The nucleus is located at the center of the atom.
• Ernest Rutherford discovered the nucleus through the gold foil experiment in 1911.

Last verified on 09-05-2026

Explanation

• Vitamin D is essential for strong bones and teeth.
• It helps the body absorb calcium and phosphorus.
• Its deficiency causes Rickets in children.
• Vitamin D = “Sunshine vitamin”
• Helps in bone mineralization
• Works with calcium to build strong skeleton

Last verified on 07-05-2026

Explanation

• Solar and wind energy are renewable sources of energy, meaning they are sustainable and will not run out.
• Solar energy is generated from the sun's rays.
• Wind energy is generated from the wind.

Last verified on 09-02-2026

Explanation

• Our Solar System is located in the Orion Arm of the Milky Way galaxy.
• It including the Sun and eight planets.
• It consists of about 100–400 billion stars along with large amounts of gas and cosmic dust.

Additional information:

• The Milky Way is a spiral galaxy with a diameter of about 100,000 light-years.
• The nearest large galaxy to the Milky Way is Andromeda, located about 2.5 million light-years away.

Last verified on 11-03-2026

Explanation

• The Sun is a star at the center of our solar system with a surface temperature of about 6000 °C (Sun’s core is even hotter, ~15 million °C).
• It provides light and heat, essential for life on Earth.
• The Sun’s energy drives weather, photosynthesis, and climate.

Last verified on 18-03-2026

Explanation

• Sun mass → 1.989 × 10³⁰ kg
• Earth mass → 5.972 × 10²⁴ kg
• Sun ≈ 330,000 Earths
• Sun contains 99.8% of solar system mass
• Earth is only 0.2% of total system mass (approx.)

Last verified on 02-05-2026

Explanation

• Digestion begins in the mouth, starting immediately when food is ingested.
• Both mechanical digestion (chewing) and chemical digestion (salivary amylase breaking down carbohydrates) 

Additional information:

• Mouth: Food is chewed and mixed with saliva that contains enzymes to break down carbohydrates.
• Esophagus: Food is swallowed and passes through the esophagus into the stomach.
• Stomach: Food is mixed with stomach acid and enzymes to break down proteins and fats.
• Small Intestine: Nutrients are absorbed into the bloodstream.
• Large Intestine: Water and electrolytes are absorbed, and waste is eliminated.

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Last updated by NS on 01 MAY 2026

Explanation

Composition of Air:

• Nitrogen → 78%
• Oxygen → 20.95%
• Argon → 0.93%
• Carbon dioxide → 0.04%
• Other gases → very small traces

Last verified on 30-04-2026

Explanation

• Vitamin A is essential for vision, skin health, and immune function.
• Its deficiency can lead to night blindness (poor ight vision) and other health problems.

Additional information:

• Dry skin and eyes
• Impaired immune function
• Poor wound healing
• Increased risk of respiratory and urinary tract infections

Last verified on 17-01-2026

Explanation

• A barometer measures atmospheric (air) pressure.
• It helps in weather forecasting, detecting storms, and studying climate changes.
• Two common types of barometers: mercury barometer and aneroid barometer.

Last verified on 13-03-2026