Explanation

• The speed of sound in air at 0°C (32°F) is 332 meters per second.

The speed of sound in different materials:

• Air: 332 m/s
• Sea water: 1530 m/s
• Lead: 2160 m/s
• Gold: 3240 m/s
• Brick: 3650 m/s
• Copper: 4760 m/s
• Glass: 5100 m/s
• Aluminium: 6420 m/s

Explanation

Smoke from industries causes Smog.

It is a type of air pollution caused by the interaction of smoke, gases, and other atmospheric pollutants.

Smog is a harmful mixture of smoke, sulfur dioxide, and other pollutants that can cause respiratory problems and other health issues.

Explanation

• The water potential of pure water is zero (0).
• It is taken as a standard reference point.
• Pure water has no dissolved solutes.
• Chemical formula: H2O
• Molar mass: 18.01528(33) g/mol
• Melting point: 0.00 °C (32.00 °F; 273.15 K) [b]
• Boiling point: 99.98 °C (211.96 °F; 373.13 K)

Last updated by NS on 20-April-2026

Explanation

Pneumonia is often caused by Streptococcus pneumoniae.

It is a type of bacteria that leads to lung inflammation and infection.

It affecting breathing and oxygen intake.

Explanation

Lithotripsy uses sound wave to breakup large kidney stones into smaller pieces.

Lithotripsy is a procedure involving the physical destruction of hardened masses

like kidney stones, bezoars or gallstones, which may be done non invasively.

The term is derived from the Greek words meaning "breaking stones".

Explanation

• Mercury is the only stable elemental metal that is liquid at standard room temperature
• Symbol and Number: Mercury has the chemical symbol Hg and atomic number 80.
• Freezing Point: It melts at -38.8°C (-37.9°F)

Explanation

A punctuation mark used to indicate an abrupt turn or break in a sentence is called a dash (specifically, an em dash

Function: To mark a sudden break or interruption in a sentence. 

Appearance: Usually longer than a hyphen. 

Example: "I was going to the store, but then - I remembered I forgot my wallet." 

Explanation

When fossil fuels are burned,

they release large amounts of carbon dioxide,

a greenhouse gas, into the air

.ND18-5-2023

Explanation

It is a highly unstable isotope of hydrogen.

Hydrogen has no neutron.

It contain only one proton and one electron.

But the deuterium contain one neutron and tritium contain two neurons,

these are the isotopes of hydrogen.

Explanation

Aluminum is the most abundant metal in the Earth's crust, and the third most abundant element therein, after oxygen and silicon.