Question

What is the Earth's atmosphere composed of 78.08 % .................... and 20.95 % .............?

• A. hydrogen, carbon dioxide
• B. nitrogen, oxygen
• C. oxygen, argon
• D. carbon dioxide, hydrogen

Answer 1

Answer:

B. nitrogen, oxygen

Atmospheric composition

• Gases, moisture and dust particles are the major constituents. It is the gravitational attraction of the earth that holds the atmosphere close to the earth.

• Atmospheric Gases and % of Composition

Nitrogen - 78.08, Oxygen – 20.95, Argon - 0.93, Carbon dioxide - 0.03, Ozone – 0.01 along with Neon, Helium, Krypton, Hydrogen, Xenon are main constituents.

• Water reaches the atmosphere through evaporation and causes cloud formation and rain.

• Factors influencing the amount of water in the atmosphere:

1. Rate of evaporation - High at places experiencing higher temperature

2. Closeness to the surface water sources such as oceans, rivers and other water bodies.

• Dust particles are brought to the atmosphere by wind, erupted through volcanic eruption and through formation of ash by burning of meteors.

• As the fine dust particles in the atmosphere help in cloud formation they are called as Condensation nuclei.