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

• 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

• 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

• 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

Explanation

• Every element is identified by the number of protons in its nucleus.
• This number determines the identity of the element.
• It is written as Z in chemistry.
• It is always equal to the number of electrons in a neutral atom.
• This is called the atomic number.

Last verified on 12-04-2026

Explanation

• Earth water coverage: 71%
• Land area: 29%
• Ocean water: 97% of total water
• Fresh water: 3% of total water
• Largest ocean: Pacific Ocean

Last verified on 10-04-2026

Explanation

• Chronometer is a highly precise time-measuring instrument.
• It is often used in navigation and scientific experiments.
• It is designed to measure time accurately, even under varying conditions.
• Chronometers played a key role in determining longitude at sea.

Last verified on 03-04-2026

Explanation

Vitamins B and C are water-soluble vitamins, meaning they dissolve easily in water.

• Vitamin B: Includes several B vitamins (B1, B2, B3, etc.), all of which are water-soluble.
• Vitamin C (Ascorbic acid): Also highly soluble in water.

Last verified on 02-04-2026

Explanation

• Platelets, also called thrombocytes.
• They are blood cells that play a vital role in blood clotting.
• When a blood vessel is injured, platelets aggregate to form a plug that stops the bleeding.

Last verified on 02-04-2026

Explanation

• The freezing (or melting) point of ice on the Fahrenheit scale is 32°F.
• This is the temperature at which ice turns from a solid to a liquid. 
• The Fahrenheit scale also defines the boiling point of water as 212°F.
• A change of 1°F on the Fahrenheit scale is less than a 1°C change on the Celsius scale.

Last verified on 02-04-2026