Explanation

If Earth had no atmosphere, the sky would appear black even during the day,

Hence, the sky would appear black, just like it does from space.

Explanation

Decibel (dB) measures the intensity or loudness of sound.

It is a logarithmic unit, meaning each 10 dB increase represents a tenfold increase in intensity.

Decibels are also used in electronics and signal strength measurements.

It does not measure speed of light or heat.

Common examples: Normal conversation ≈ 60 dB, threshold of hearing ≈ 0 dB, jet engine ≈ 120 dB.

Explanation

• Comets are small celestial bodies made of ice, dust, and rock.
• When they approach the Sun, they form bright tails of gas and dust.

• Often called “dirty snowballs” due to icy composition.
• Comets follow highly elliptical orbits around the Sun.

Last verified on 19-01-2026

Explanation

The volume of a sphere is the total space it occupies, calculated using the formula V = (4/3)πr³

V: Volume

π (Pi): A mathematical constant (approx. 3.14159).

r³ (Radius Cubed): The radius multiplied by itself three times (r × r × r). 

Explanation

One barrel of petroleum is a standard unit of measurement in the oil industry.

It equals 42 US gallons, which is approximately 159 liters.

In cubic meters, it is roughly 0.159 m³.

The UK gallon is larger, so one barrel equals about 34.97 UK gallons.

This unit is used worldwide for oil production, trading, and pricing