Lakhmir Singh & Manjit Kaur Test: Natural Resources - Class 9 MCQ

Chemicals Responsible for Ozone Hole:
The chemicals responsible for the formation of the ozone hole are primarily chlorofluorocarbons (CFCs). These chemicals are human-made substances that were commonly used in various industries, such as refrigeration, aerosol propellants, and foam-blowing agents. When released into the atmosphere, CFCs can rise to the stratosphere, where they undergo chemical reactions that break down ozone molecules.
Explanation:
1. Chlorofluorocarbons (CFCs):
- CFCs are the main culprits behind the depletion of the ozone layer.
- They are chemically stable and can remain in the atmosphere for several decades, allowing them to reach the stratosphere.
- In the presence of ultraviolet radiation, CFCs release chlorine atoms, which then catalytically destroy ozone molecules.
2. Acidic gases:
- Acidic gases, such as sulfur dioxide (SO2) and nitrogen oxides (NOx), can contribute to the formation of acid rain.
- While acid rain does not directly cause the ozone hole, it can indirectly affect ozone levels by altering atmospheric conditions.
3. Greenhouse gases:
- Greenhouse gases, such as carbon dioxide (CO2) and methane (CH4), are responsible for trapping heat in the Earth's atmosphere, leading to global warming.
- While they do not directly cause the ozone hole, they can indirectly impact ozone levels by affecting atmospheric temperatures and circulation patterns.
4. Peroxyacetyl nitrate (PAN):
- PAN is a secondary pollutant formed from the reaction of volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the presence of sunlight.
- While PAN does not directly cause the ozone hole, it can contribute to the destruction of ozone molecules in polluted areas.
In conclusion, the primary chemical responsible for the ozone hole is chlorofluorocarbons (CFCs). These human-made substances release chlorine atoms in the stratosphere, which then catalytically destroy ozone molecules. While other chemicals, such as acidic gases and greenhouse gases, can indirectly affect ozone levels, they are not the main causes of the ozone hole.

Clouds are formed by the process of evaporation of water from large water bodies like sea, river, lake, etc that results in formation of water vapours. These water vapours after condensation turned into rain droplets.

Explanation:
The water droplets found on the inner surface of the plate are due to condensation. Here's a detailed explanation:
Condensation:
- Condensation is the process in which a substance changes from its gaseous state to its liquid state.
- It occurs when the temperature of the gas is lowered below its dew point, causing the gas molecules to lose energy and come together to form liquid droplets.
- In this case, the hot water inside the vessel releases vapor into the air above it.
- When the hot vapor comes into contact with the colder surface of the plate, it loses heat energy and condenses into liquid droplets.
- These liquid droplets then accumulate on the inner surface of the plate, forming water droplets.
Other Options:
- Sublimation refers to the process in which a substance changes from its solid state directly to its gaseous state without passing through the liquid state. This is not applicable in this scenario.
- Vaporization refers to the process in which a substance changes from its liquid state to its gaseous state. While the hot water is vaporizing, the water droplets on the plate are not a result of this process.
- Evaporation refers to the process in which a substance changes from its liquid state to its gaseous state at a temperature below its boiling point. The water droplets on the plate are not a result of evaporation.
Therefore, the correct answer is B: Condensation.

Increased levels of carbon dioxide cause global warming
- Carbon dioxide (CO2) is a greenhouse gas that contributes to global warming.
- When there is an increase in the concentration of CO2 in the atmosphere, it leads to a rise in global temperatures.
- CO2 traps heat from the sun within the Earth's atmosphere, preventing it from escaping back into space.
- This process is known as the greenhouse effect and is essential for maintaining Earth's temperature for supporting life.
- However, human activities such as burning fossil fuels, deforestation, and industrial processes have significantly increased the levels of CO2 in the atmosphere.
- The increased concentration of CO2 enhances the greenhouse effect, leading to global warming.
- Global warming has various negative impacts, including rising sea levels, extreme weather events, and disruptions to ecosystems.
- It is crucial to reduce CO2 emissions and transition to cleaner and more sustainable energy sources to mitigate the effects of global warming.

Because smog is made from smoke and fog.

Ammonia fits that description, but it is not long-lived in the atmosphere and it is not widespread. So, even though ammonia is a good infrared absorber, it is not an important greenhouse gas.

Major Component of Atmosphere on Mars:
- The major component of the atmosphere on Mars is carbon dioxide (CO2).
- The concentration of carbon dioxide in the Martian atmosphere is about 95%.
- This high concentration of carbon dioxide makes the Martian atmosphere thinner and colder compared to Earth's atmosphere.
- The presence of carbon dioxide in the Martian atmosphere contributes to the red color of the planet's surface.
- The carbon dioxide in the atmosphere also plays a role in the weather patterns on Mars, including the formation of dust storms.
- Other components of the Martian atmosphere include nitrogen (about 2.6%), argon (about 1.9%), and traces of oxygen, water vapor, and methane.
- The presence of these trace gases is very low compared to carbon dioxide.
In summary:
- The major component of the atmosphere on Mars is carbon dioxide, with a concentration of about 95%.
- Nitrogen, argon, oxygen, water vapor, and methane are present in trace amounts in the Martian atmosphere.

Acid rain is due to:
There are several reasons behind the occurrence of acid rain, but the main cause is air pollution. Here is a detailed explanation:
Air pollution:
- Acid rain is primarily caused by the emission of pollutants into the atmosphere, such as sulfur dioxide (SO2) and nitrogen oxides (NOx).
- These pollutants are released from various sources, including industrial activities, power plants, and vehicles.
- When these pollutants mix with the air, they react with water, oxygen, and other chemicals to form acidic compounds.
- These acidic compounds can then be transported long distances by winds and eventually fall to the Earth's surface as acid rain.
Effects of acid rain:
- Acid rain has detrimental effects on the environment, including damage to forests, lakes, and aquatic ecosystems.
- It can leach nutrients from the soil, making it difficult for plants to grow and affecting agricultural productivity.
- Acid rain also corrodes buildings, statues, and other structures made of stone or metal.
Prevention and control:
- To prevent acid rain, it is crucial to reduce the emissions of sulfur dioxide and nitrogen oxides.
- This can be achieved by implementing stricter regulations on industrial emissions, using cleaner technologies, and promoting renewable energy sources.
- International cooperation is also necessary to address the issue, as acid rain can be transported across borders.
In conclusion, acid rain is primarily caused by air pollution, particularly the emission of sulfur dioxide and nitrogen oxides. It is crucial to take measures to reduce these emissions and prevent the harmful effects of acid rain on the environment.

Reasons for the wide range of temperature on the surface of the moon:
There are several factors that contribute to the wide range of temperature on the surface of the moon:
1. Absence of atmosphere: Unlike Earth, the moon does not have a significant atmosphere. The lack of an atmosphere means there is no air to trap heat or regulate temperature. As a result, the moon experiences extreme temperature fluctuations.
2. Day-night cycle: The moon rotates on its axis, resulting in a day-night cycle similar to Earth. During the 14-day long lunar day, the surface is exposed to the intense heat of the sun, causing temperatures to rise significantly. Conversely, during the 14-day long lunar night, temperatures drop drastically due to the absence of sunlight.
3. Lack of insulation: The moon's surface does not have any insulating materials like Earth's soil or vegetation. This means that heat absorbed during the day is quickly radiated back into space during the night, leading to rapid cooling.
4. Slow heat transfer: The moon's surface does not have a significant atmosphere or liquid water, which are efficient conductors of heat. As a result, the transfer of heat on the moon's surface is relatively slow, leading to temperature extremes.
In conclusion, the wide range of temperature on the moon's surface is primarily due to the absence of an atmosphere, the day-night cycle, lack of insulation, and slow heat transfer. These factors contribute to the extreme temperature fluctuations experienced on the moon.

The coastal areas during day time are characterized by:
- Movement of air from sea towards land: During the day, the land heats up faster than the water, creating a temperature gradient. This temperature difference causes the air to move from the cooler sea towards the warmer land.
- Sea breeze: The movement of air from the sea towards the land is known as a sea breeze. This breeze is typically gentle and brings cooler air from the sea, providing relief from the heat on the coast.
- Cooling effect: The sea breeze helps to moderate the temperature in coastal areas during the day. It brings in cooler air, which can lower the temperature and make the surroundings more comfortable.
- Moisture: The sea breeze also carries moisture from the sea, leading to higher humidity levels in coastal areas. This increased humidity can impact the weather conditions and contribute to the formation of clouds or precipitation.
- Local wind patterns: The movement of air from the sea towards the land creates local wind patterns along the coast. These patterns can vary depending on factors such as topography, temperature differentials, and atmospheric conditions.
Overall, during the day, coastal areas are characterized by the movement of air from the sea towards the land, creating a sea breeze that brings cooler air and increased humidity. This phenomenon plays a significant role in shaping the climate and weather conditions along the coast.