Solved Questions on Water and Air
1. Which of the following statements is true about water?
a) Water is not essential for the existence of living organisms.
b) Freshwater accounts for about 97% of the Earth's surface.
c) Rainwater, groundwater, rivers, and sea are sources of water.
d) Water cycle involves only the processes of evaporation and precipitation.
Answer: c) Rainwater, groundwater, rivers, and the sea are sources of water. All the other statements are false.
2. In an experiment, a burning candle is placed inside a jar. After a few minutes, the flame starts to flicker and eventually goes out. Which gas in the jar is consumed by the flame?
a) Nitrogen
b) Oxygen
c) Carbon dioxide
d) Helium
Answer: b) The gas in the jar that is consumed by the flame is oxygen. Oxygen is necessary for combustion, and the flame of the candle utilizes the oxygen in the air to sustain the burning process. As the flame burns, it consumes all the available oxygen in the jar until it extinguishes.
3. Consider the following statements and choose the correct option:
Statement I: Drought occurs when there is excessive rainfall in a region for an extended period.
Statement II: Drought can lead to water scarcity and shortage of food.
a) Statement I is correct but statement II is incorrect.
b) Statement I is incorrect but statement II is correct.
c) Both statements are correct.
d) Both statements are incorrect.
Answer: b) Drought actually occurs when there is a prolonged period of significantly below-average rainfall in a region, leading to a shortage of water resources. This scarcity of water can then have many effects, including a shortage of food due to the impact on agriculture.
4. Which of the following functions does air serve in the water cycle?
a) Air carries water vapour from the oceans to the land.
b) Air helps regulate the temperature of the Earth's surface.
c) Air condenses water vapour into clouds.
d) All of the above.
Answer: d) Air serves multiple functions in the water cycle. It carries water vapour from the oceans to the land, helping in the process of evaporation and transportation of moisture. Air also helps regulate the temperature of the Earth. Additionally, air plays a crucial role in the condensation of water vapour, forming clouds and eventually leading to precipitation.
5. Fill in the blanks.
The __________ is the layer of the atmosphere where the International Space Station (ISS) orbits. Below it lies the __________.
a) Exosphere / Thermosphere
b) Mesosphere / Thermosphere
c) Stratosphere / Troposphere
d) Thermosphere / Mesosphere
Answer: a) The Exosphere is the outermost layer of the Earth's atmosphere and it extends into space. This is where satellites, including the International Space Station (ISS), orbit around the Earth. Below the Exosphere is the Thermosphere, which is the layer where the temperature increases with altitude.
FAQs
1. What are the different forms of water in the atmosphere?
Water is found in the atmosphere as vapor, clouds, and precipitation (rain, snow, and sleet).
2. Why is air essential for combustion (burning)?
Air contains oxygen, which is a necessary component for combustion. When chemicals burn, they react with oxygen from the atmosphere.
3. What is the composition of air?
Air is a mixture of gases, primarily nitrogen (78%) and oxygen (21%), along with traces of other gases like carbon dioxide and argon.
4. What is the percentage of nitrogen in air?
The percentage of nitrogen in Earth's atmosphere is approximately 78%. Nitrogen is the most abundant gas in the atmosphere, with oxygen being the second most prevalent at around 21%.
5. What is Water vapour?
Water vapor is the gaseous form of water. When water is heated, it turns into water vapor, which is an invisible gas that floats in the air. It's part of the water cycle, where water changes between liquid, gas (water vapor), and solid (ice) forms.
