Explanation

• The speed of sound is maximum in solids 
• Because particles are tightly packed, allowing faster vibration transfer.
• In iron, sound travels around 5120 m/s,
• Much faster than in air (343 m/s) or water (1482 m/s).

Last updated 17 july 2026 by NA

Explanation

• Surface tension prevents water from penetrating waterproof materials.

Additional information 

• Friction: Force that opposes the motion between two surfaces in contact.
• Adhesion: Attraction between molecules of different substances.
• Gravity: Force that pulls objects toward the Earth

Last updated by NA on 16-07-2026

Explanation

• 24-karat (24K) gold is considered the "best"
• Purity: 99.9% pure gold.
• Color: Rich, deep, bright yellow.

Additional information

• 22K Gold: 91.7% pure gold. It is mixed with harder metals like silver or copper.
• 18K Gold: 75% pure gold. It is highly durable and excellent for diamond settings 
• Carat is the unit of measurement for the physical weight of diamonds/gold.

Last updated by NA on 16-07-2026

Explanation

• When the volume of a gas decreases at constant temperature, its pressure increases.
• This relationship is explained by Boyle's Law.
• Boyle's Law states that pressure is inversely proportional to volume when temperature remains constant.

Verified & Updated

Explanation

• Venus comes closest to Earth when it is between Earth and the Sun.

• Minimum distance: about 24 million miles (≈ 38 million km).

• This close approach occurs roughly every 584 days.

Additional Information:

• Mercury can be about 33 million miles away when Venus is on the far side of the Sun.

Last verified on 17-01-2026