Test: Atmosphere - 1 - ACT MCQ

The statement "It lies above the mesosphere" is incorrect when referring to the stratosphere.

• The stratosphere is actually located above the troposphere, which is the lowest layer of the Earth's atmosphere.
• The stratosphere extends from about 10 to 50 kilometers (6 to 31 miles) above the Earth's surface. 

The gas with the maximum percentage in the atmosphere is nitrogen.

• It comprises 78.08% of the Earth's atmosphere by volume.
• Nitrogen is an inert gas, which means that it does not react easily with other substances.
• It is essential for plant growth, as it is the main component of the atmosphere that plants use for photosynthesis.

The second most abundant gas in the atmosphere is oxygen.

• It comprises 20.95% of the Earth's atmosphere by volume.
• Oxygen is essential for life, as it is the gas that humans and other animals breathe.
• It is also used in combustion reactions, such as burning wood or gasoline.

Ozone layer

• The ozone layer is a natural layer of gas in the upper atmosphere that protects humans and other living things from harmful ultraviolet (UV) radiation from the sun.
• The ozone layer exists in the stratosphere, a layer 10 to 50 km above the Earth’s surface.
• The international community established the Montreal Protocol on ozone-depleting substances in 1987, to address the destruction of the ozone layer.
• The stratospheric ozone layer absorbs ultraviolet (UV) radiation, preventing dangerous UV rays from hitting the Earth's surface and harming living organisms.
• It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere.
• The ozone layer in the stratosphere is affected by the increase in the atmospheric concentration of CFC (chlorofluorocarbons).
• In the atmosphere, CFCs drift slowly upward to the stratosphere, where they are broken up by ultraviolet radiation, releasing chlorine atoms, which can destroy ozone molecules.
• CFCs are the main reason for the Ozone hole.
• The other reasons for ozone depletion are a wide range of industrial and consumer applications, mainly refrigerators, air conditioners (hydrochlorofluorocarbons (HCFCs), and fire extinguishers.

The atmospheric layer that contains ions and facilitates wireless communication is the thermosphere. This layer of the Earth's atmosphere is characterized by high temperatures and the presence of ionized gases, which enables the reflection of radio waves and facilitates long-distance radio communication, including satellite communication and some forms of radio broadcasting.

The highest layer of the atmosphere in which meteors burn up after entering Earth's atmosphere is the mesosphere. This layer is located above the stratosphere and below the thermosphere. Meteors, also known as shooting stars, typically burn up in the mesosphere due to the high temperatures generated by their high-speed entry into the atmosphere.

The ionosphere is the upper layer of the Earth’s atmosphere.

• The atmosphere is partly ionized by solar UV-light, and such ionization can persist at high altitudes.
• The ionosphere starts at about 80 km altitude and reaches up to more than 1000 km.
• This area of the atmosphere consists of several conductive layers that reflect radio waves, a characteristic that is of interest to scientists and engineers, especially in the telecommunications industry.

Precipitation is any form of water that falls from the atmosphere and reaches the Earth's surface. It can take several forms, including rain, snow, sleet, and hail.

A) Flood is not a form of precipitation.

• Floods occur when there is an excessive amount of water in a river or other body of water, causing it to overflow onto the surrounding land.

B) Snow is a form of precipitation

• that occurs when water vapor in the atmosphere freezes into ice crystals. These ice crystals combine to form snowflakes, which fall to the ground as snow.

C) Hail is a form of precipitation

• that occurs during thunderstorms, when strong updrafts carry raindrops high into the atmosphere, where they freeze into ice.
• These ice particles can then grow larger as they are carried up and down by the storm's updrafts, eventually falling to the ground as hailstones.

D) Sleet is a form of precipitation

• that occurs when raindrops fall through a layer of freezing air near the ground, causing them to freeze into ice pellets before reaching the ground.

Therefore, the forms of precipitation are rain, snow, and sleet, making option (2) (A), (B), (D) the correct answer

The Earth's atmosphere is divided into several layers based on the variation of temperature with altitude. One of these layers is the thermosphere, which lies above the mesopause, the boundary between the mesosphere and the thermosphere.

The thermosphere is characterized by a significant increase in temperature with altitude. This increase occurs primarily due to the absorption of solar radiation by certain gases present in this region, particularly oxygen and nitrogen. When solar radiation enters the thermosphere, it interacts with these gases, causing them to absorb energy and heat up. This process leads to higher temperatures at higher altitudes within the thermosphere.

Despite the high temperatures, the thermosphere is not perceived as hot in the conventional sense because the atmosphere at such altitudes is extremely thin. The density of molecules in the thermosphere is very low, which means that even though individual molecules are moving rapidly due to their high kinetic energy, there are very few of them to transfer heat to other objects.

It's important to note that the thermosphere is also the region where phenomena such as the auroras occur. Solar particles interact with the gases in the thermosphere, causing them to emit light and produce the stunning displays of the auroras, commonly known as the northern and southern lights.

Furthermore, the thermosphere is the layer where many satellites orbit the Earth. The low density of gas molecules allows satellites to travel with less drag, making it an ideal region for space missions and satellite operations.

In summary, the thermosphere lies above the mesopause and is characterized by increasing temperatures with altitude due to the absorption of solar radiation. Despite the high temperatures, the thin atmosphere at this altitude means that the thermosphere does not feel hot in the conventional sense. It plays crucial roles in phenomena such as the auroras and is essential for satellite operations and space exploration.

The troposphere is the lowest layer of Earth's atmosphere, extending from the surface to roughly 8 to 15 kilometers (5 to 9 miles) above sea level, depending on latitude and season. It contains about 70-80% of the total mass of the atmosphere and is where most weather phenomena occur.

 Mesosphere - 

• It extends above the stratosphere up to a height of about 80 km.
• It is the coldest layer of the atmosphere.
• The mesosphere is directly above the stratosphere.
• The stratosphere and mesosphere are collectively termed as " Middle atmosphere 
• Within the mesosphere, temperature decreases with increasing height, due to decreasing solar heating and increasing cooling by CO₂ radiative emission.