Explanation

• The hardest substance in the world is diamond.
• Its hardness is due to the strong covalent bonding between its carbon atoms.
• This making it the most resistant to scratching.

Additional information:

• Category: Native minerals
• Cleavage: 111 (perfect in four directions)
• Crystal class: Hexoctahedral (m3m); H-M symbol: (4/m 3 2/m)
• Crystal habit: Octahedral
• Crystal system: Cubic
• Dana classification: 1.3.6.1
• Density: 3.5–3.53 g/cm3 3500–3530 kg/m3

Last verified on 07-06-2026

Explanation

• An electric generator is a device that converts mechanical energy into usable electrical energy.
• This process is based on the principle of electromagnetic induction.
• Discovered in 1831 by British scientist Michael Faraday.

Last verified on 27-04-2026

Explanation

• Copper (تانبا) is a good conductor of electricity.
• It allows electric current to flow easily.

Additional information:

• Metals are generally good conductors.
• Non-metals usually do not conduct electricity.
• Good Conductors: Copper, Silver, Gold, Aluminum, Graphite
• Bad Conductors: Plastic, Rubber, Wood, Glass, Air

Last verified on 07-06-2026

Explanation

• Alexander Fleming discovered Penicillin
• At St. Mary's Hospital in London
• In September 1928.
• First true antibiotic used to treat bacterial infections.
• First patient treated was Albert Alexander, a 43-year-old policeman, on 12 February 1941

Last updated by NA on 23-April-2026

Explanation

Surface area = 4πr², Volume = 4/3πr³.  

Surface area is just derivative of volume w.r.t r.

2πr is circumference of a circle, not volume at all.

Last verified on 07-06-2026

Explanation

• Diamond is a naturally occurring allotropic form of carbon.
• Allotropy means a single element can exist in more than one form with different structures and properties.
• It is extremely hard.
• It has a high melting point.
• It is widely used in jewelry and cutting tools.

Additional information:

• Graphite – soft, good conductor
• Fullerenes (C60) – spherical molecules
• Carbon nanotubes – tubular, high strength
• Amorphous carbon – coal, soot
• Lonsdaleite – hexagonal diamond

Last verified on 17-01-2026

Explanation

• Battery is a device that converts chemical energy into electrical energy.
• Batteries work by using a galvanic cell.
• It is an electrochemical device made up of two electrodes and an electrolyte solution.

Last verified on 16-03-2026

Explanation

• Nicolaus Copernicus is called the Father of Modern Astronomy.
• He introduced the heliocentric theory in 1543.
• This theory stated that the Sun is at the center of the solar system.
• His ideas changed the old belief that Earth is the center.

Additional information:

• Galileo Galilei, a later figure, is often called the "father of observational astronomy".

Last verified on 01-06-2026

Explanation

• The Earth’s circumference at the equator is about 40,075 km (24,901 miles).
• Measured through the poles, it is slightly smaller: 40,008 km (24,860 miles).
• The difference is due to the equatorial bulge caused by Earth's rotation.
• Diameter: ~12,756 km (7,926 miles).
• Age of Earth: ~4.453 billion years.

Last verified on 31-03-2026

Explanation

• The largest planet in our solar system is Jupiter.
• 5th planet
• 79 known moons (Maximum number of moons)
• The Great Red Spot is a prominent feature
• Giant planet and the fastest-rotating planet 
• Rotates approximately once every 10 hours.
• Age is about 4.603 billion years.

Additional information

• Mercury is the smallest planet of the solar system.

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Last updated by NA on 25-April-2026