Short & Long Questions: The Atmosphere | Window on the Word Class 7: Solutions, Notes & Worksheets PDF Download

Short Answer Questions

Q1: What holds the atmosphere to the Earth's surface? 
Ans: The atmosphere is held to the Earth's surface by the planet's gravitational force.

Q2: Which gas makes up the majority of the Earth's atmosphere? 
Ans: Nitrogen makes up about 78% of the Earth's atmosphere.

Q3: Why is oxygen important in the atmosphere? 
Ans: Oxygen is essential for the survival of humans, plants, and many other organisms as it is used for respiration and energy production.

Q4: What is the greenhouse effect, and how does it relate to global warming?
Ans: The greenhouse effect is when certain gases in the atmosphere, like carbon dioxide, trap heat and prevent it from escaping into space, keeping the Earth warm. Human activities, such as burning fossil fuels, increase the amount of these gases, leading to global warming.

Q5: What are the layers of the Earth's atmosphere from the surface upward?
 Ans: The layers of the Earth's atmosphere, from the surface upward, are the troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

Q6: What is the primary function of the ionosphere in the thermosphere? 
Ans: The ionosphere in the thermosphere reflects radio waves, making it important for radio communication and the propagation of signals.

Q7: What are permanent winds, and give an example of one? 
Ans: Permanent winds blow consistently throughout the year and are related to the permanent pressure belts. An example is the trade winds.

Q8: How does altitude affect atmospheric temperature, and why are mountains colder than plains? 
Ans: As altitude increases, atmospheric temperature decreases at a rate of about 1°C for every 165 meters of ascent. Mountains are colder than plains because the air at higher altitudes is thinner and has fewer particles to absorb heat.

Q9: What is humidity, and how does it change with temperature? 
Ans: Humidity is the amount of moisture in the air. It increases with rising temperatures because warm air can hold more moisture.

Q10: Name one type of precipitation and briefly explain how it forms. 
Ans: One type of precipitation is rain. It forms when water droplets in clouds become large and heavy and fall to the Earth due to gravity.

Long Answer Questions

Q1: Describe the composition of the Earth's atmosphere, including the role of nitrogen, oxygen, and carbon dioxide. Provide a simple diagram to illustrate this. 
Ans: The Earth's atmosphere is composed mainly of nitrogen (78%) and oxygen (21%). These gases are essential for life. Carbon dioxide, though a small percentage (0.04%), is vital for photosynthesis. Plants absorb nitrogen from the soil with the help of bacteria.

Q2: Differentiate between weather and climate, and explain the key elements that indicate each. 
Ans: Weather refers to the short-term atmospheric conditions over a few hours or a day, including elements like temperature, humidity, precipitation, winds, and pressure. Climate, on the other hand, represents the long-term average of these elements over about 30 years or more.

Q3: Explain the factors that influence climate, including atmospheric temperature, air pressure, and winds. Provide examples to illustrate the impact of these factors. 
Ans: Atmospheric temperature, influenced by latitude, altitude, and proximity to the sea, plays a vital role in climate. Air pressure and winds, such as the trade winds, westerlies, and polar easterlies, also affect climate. For instance, regions closer to the equator tend to be hotter due to the direct impact of the Sun.

Q4: Describe the major pressure belts of the Earth, their formation, and how they influence the movement of winds. 
Ans: Major pressure belts include the equatorial low pressure belt, subtropical high pressure belts, subpolar low pressure belts, and polar high pressure belts. These belts are created by the movement of air due to differences in temperature and the Earth's rotation. Winds move from high-pressure areas to low-pressure areas, influencing global wind patterns.

Q5: Explain the different types of rainfall, including convectional, relief, and cyclonic rainfall. Provide examples of regions where each type occurs. 
Ans: Convectional rainfall occurs near the equator due to heating of the land, while relief rainfall occurs when moist air is forced to rise over mountains. Cyclonic rainfall is associated with tropical storms and occurs both in tropical and temperate regions due to the convergence of warm and cold air masses.

Q6: Describe the importance of the ionosphere in the thermosphere and its role in radio communication. 
Ans: The ionosphere is a layer in the thermosphere that reflects radio waves. This property makes it crucial for long-distance radio communication, as signals transmitted from Earth bounce off the ionosphere and travel longer distances.

Q7: Explain how the greenhouse effect contributes to global warming and the adverse effects of global warming on the environment.
Ans: The greenhouse effect is when greenhouse gases trap heat in the Earth's atmosphere, keeping it warm. Increased levels of greenhouse gases due to human activities have led to global warming. This, in turn, causes climate change, melting of ice caps, rising sea levels, and disruptions to ecosystems.

Q8: Discuss the occurrence of cyclones in Odisha, their impact, and the measures taken to mitigate their effects in recent years. 
Ans: Odisha is prone to cyclonic activity due to its location along the Bay of Bengal. Cyclones in 1999 caused widespread destruction and loss of life. However, in 2013, the state government took preparedness measures like constructing safe houses and conducting evacuation drills, which significantly reduced the impact of Cyclone Phailin.

Q9: Explain the concept of humidity, including the differences between absolute humidity and relative humidity. Discuss how temperature affects humidity. 
Ans: Humidity refers to the amount of moisture in the air. Absolute humidity measures the actual quantity of water vapor in a given volume, while relative humidity expresses the ratio between the amount of moisture present and the air's capacity to hold moisture at a specific temperature. Humidity generally rises with higher temperatures.

Q10: Discuss the formation of land and sea breezes and provide an example of a local wind. Explain how temperature differences over land and water lead to these breezes. 
Ans: Land and sea breezes occur daily along coastlines. During the day, land heats up faster than the sea, causing low pressure over land and sea breezes blowing from the sea. At night, the land cools more quickly, creating low pressure over the sea and leading to land breezes from the land. An example of a local wind is the "loo," which blows hot and dry over the western Indo-Gangetic Plain during summer.