Explanation

• Geostationary satellites are located directly above the equator. 
• Altitude: About 35,786 kilometers (22,236 miles) above sea level.
• Speed and Direction: Moves from west to east, matching the Earth's rotation speed.
• Time Period: Exactly 24 hours (one rotation day). 

Last updated 26-07-2026 by NA

Explanation

• Sunlight travels at the speed of light (~3 × 10⁸ m/s).
• Takes 8 minutes 20 seconds on average to reach Earth.
• Sunlight takes approximately 499 seconds to travel from the Sun to Earth.
• Distance traveled: 150 million km from Sun to Earth.
• Moonlight takes only 1.3 seconds to reach Earth.

Last verified on 13-03-2026

Explanation

• A rainbow is produced due to the dispersion of sunlight by water droplets in the atmosphere.
• White sunlight splits into seven colours when it passes through raindrops.
• The formation of a rainbow involves refraction, dispersion, and internal reflection.
• Dispersion is the phenomenon responsible for separating white light into its constituent colours.
• Rainbows are usually seen opposite the Sun after rainfall.

Last verified on 26-07-2026

Explanation

• Rutherford’s gold foil experiment (1911) showed that an atom has a small, dense, positively charged center called the nucleus.
• The mass of the atom is concentrated in the nucleus, while most of the atom is empty space.

Additional information:

• Nucleus contains: Protons (+) and neutrons (neutral)
• Electrons move around the nucleus in mostly empty space
• The experiment involved alpha particles being deflected by the nucleus.

Last verified on 10-02-2026

Explanation

Kelvin = °C + 273

27 + 273 = 300 K.

Last verified on 06-07-2026

Explanation

• Anthropology is the study of human life, culture, and societies.
• It examines human origins, customs, beliefs, languages, traditions, and cultural development.
• Anthropology helps us understand how humans have evolved and how different cultures function.

Additional information:

• Sociology: Human society and social relationships.
• Psychology: Human mind and behavior.
• Biology: Living organisms and life processes.

Last verified on 21-07-2026

Explanation

• The value 332 m/s is measured under standard atmospheric conditions.

Additional information:

• Speed of sound in air at 20°C ≈ 343 m/s.
• Speed of sound is faster in solids than liquids and gases.

Examples:

• Air: ~332 m/s (0°C)
• Water: ~1,480 m/s
• Steel: ~5,100 m/s

Last verified on 21-07-2026

Explanation

• Venus is called the Morning Star and Evening Star.
• It is the second closest planet to the Sun.
• It is the brightest planet and the hottest planet in the Solar System.
• It has no natural moon (satellite).
• It is also known as the "Black Planet".

Last verified on 21-07-2026

Explanation

• An Astronomical Unit (AU) is the average distance between the Earth and the Sun.
• It is a standard unit used to measure distances within the Solar System.
• 1 AU = 149,597,870.7 km
• 1 AU = 92,955,807.3 miles
• Light travels 1 AU in: About 8 minutes 20 seconds

Last verified on 21-07-2026

Explanation

• Mercury is the only elemental metal that at room temperature is Liquid.
• Mercury (Hg) is the only metal that remains liquid at room temperature (about 25°C).

Additional information:

• Chemical Symbol: Hg
• Atomic Number: 80
• Melting Point: −38.83°C
• Boiling Point: 356.73°C

Last verified on 20-07-2026