Explanation

• Earth is called the Blue Planet.
• About 71% of Earth's surface is covered by water.
• Water makes Earth appear blue from space.
• Earth is the third planet from the Sun.
• Earth’s natural satellite is the Moon

Last updated: NA on 26-09-2026

Explanation

• The Theory of Relativity was proposed by Albert Einstein.
• It was introduced in the early 20th century.
• It includes Special Relativity (1905) and General Relativity (1915).
• The theory explains the relationship between space, time, and gravity.

Last verified on 02-04-2026

Explanation

• The SI unit of energy is the Joule (J).
• It is the unit of energy, work, and heat.

Additional information:

• 1 Joule (J) = 1 Newton × 1 meter
• Calorie – 1 cal = 4.184 J
• Kilowatt-hour (kWh) – 1 kWh = 3.6 × 10⁶ J
• Electronvolt (eV) – 1 eV ≈ 1.602 × 10⁻¹⁹ J
• Erg (CGS unit) – 1 erg = 10⁻⁷ J

Last verified on 17-01-2026

Explanation

• Venus is the brightest planet in the night sky.
• Due to its thick cloud cover that reflects sunlight strongly.
• It is often called the “Evening Star” or “Morning Star.”

Additional information:

• Distance from Sun: ~108 million km
• Diameter: 12,104 km
• Orbital Period: 225 Earth days
• Atmosphere: Thick CO₂ clouds, very reflective

Last verified on 15-01-2026

Explanation

• Cause: Mainly due to sulfur dioxide (SO₂) released from burning fossil fuels like coal and oil.
• Effect: SO₂ reacts with water vapor in the atmosphere to form sulfuric acid, causing acid rain.

Last verified on 08-02-2026