CBSE Class 9 Social Science Chapter 03 Atmosphere And Climate MCQs Set 02

Answer: (A) 21%

Explanation:
Oxygen makes up 21 per cent of the air around us, just behind nitrogen's 78 per cent share. The remaining gases, including argon (0.93%) and carbon dioxide (0.04%), form only a tiny fraction of the total.

Answer: (A) Oxygen

Explanation:
Nitrogen and oxygen together dominate the atmosphere and are essential to life, while argon, krypton and xenon are grouped as minor gases found in much smaller quantities.

Answer: (A) Troposphere, Stratosphere, Mesosphere, Thermosphere

Explanation:
• Troposphere sits closest to the ground and holds our weather
• Stratosphere comes next, home to the ozone layer
• Mesosphere follows, where meteors burn up
• Thermosphere lies above that, extending toward the exosphere

Answer: (A) It holds most of the atmosphere's water vapour and clouds

Explanation:
Since the troposphere concentrates most of the moisture and cloud cover in the atmosphere, it naturally becomes the stage for rainfall, fog and similar phenomena. The ozone-filtering and meteor-burning happen in higher layers instead.

Answer: (B) 50 kilometres

Explanation:
The stratosphere stretches up to about 50 km, well beyond the troposphere's 12 km ceiling, and stops short of the mesosphere's 80 km limit.

Answer: (A) Presence of water vapour in the air

Explanation:
Humidity is simply the moisture content of the air caused by water vapour, and warmer air can hold more of it, which is why humid days feel sticky and clothes dry slowly.

Answer: (A) To help students see how everyday choices in travel, electricity, water and waste use add up to their carbon footprint and encourage better habits

Explanation:
By scoring their own transport, electricity, water and waste habits, students get a personal, relatable sense of how ordinary daily decisions contribute to greenhouse gas emissions, and the pledge step nudges them toward change.

Answer: (A) To push students to think critically about causes, preventability, and disaster response themselves

Explanation:
• The questions ask students to weigh natural versus human causes
• They invite thinking on whether planning could have limited damage
• They point students toward NDMA guidelines and youth's role in preparedness
This open-ended approach turns the case study into a reflective exercise rather than a simple fact recall.

Answer: (A) April to June, extending into July in the north-west

Explanation:
The pre-monsoon heat builds through April and June across most of the country, though in north-western India it can stretch on into July before the rains arrive.

Answer: (A) Because their climate is more temperate than the rest of the country

Explanation:
The cooler, temperate conditions found in the mountains create noticeable transitional periods that the IMD's four broad national seasons do not capture elsewhere in the country.

Answer: (A) 0.04 per cent

Explanation:
The pie diagram breaks the atmosphere into nitrogen (78%), oxygen (21%), argon (0.93%), and carbon dioxide at a tiny 0.04%, with other gases making up the rest.

Answer: (A) They burn up while passing through the mesosphere

Explanation:
The chapter notes this as a defining feature of the mesosphere, the third layer of the atmosphere, where friction with air particles causes incoming meteorites to burn up before reaching lower layers.

Answer: (A) Gravity

Explanation:
Gravity is described as the pull that keeps the atmosphere close to the planet instead of drifting off into space.

Answer: (A) Widespread damage occurs and it is rarely experienced

Explanation:
Storm-force winds, ranging from 103–117 km/hr in the table, are marked as rare occurrences that usually cause widespread damage, unlike the milder calm, light breeze, or strong breeze categories.

Answer: (A) The north-west stays around 10-15°C while the south-east warms up to about 20-25°C

Explanation:
Because insolation and distance from the equator affect temperature distribution, the chapter notes that December-January temperatures rise as one moves from the cooler north-west towards the warmer south-eastern parts of mainland India.

Answer: (A) Varahamihira

Explanation:
Krishiparashara's approach instead tracked the Sun and Moon's general positions, while Kautilya's Arthashastra dealt with rainfall records for revenue purposes, and Kalidasa merely described the monsoon's path poetically in Meghadutam. Varahamihira specifically used nakshatra positions for his predictions.

Answer: (A) Carbon dioxide

Explanation:
Human activities are said to raise levels of greenhouse gases like carbon dioxide, methane, nitrous oxide, and water vapour, with carbon dioxide from burning fuels being the most emphasised contributor to rising global temperatures.

Answer: (A) Western disturbances bringing extra moisture

Explanation:
The case study explains that western disturbances added further moisture and rain on top of the monsoon downpours, worsening conditions across Punjab, Himachal Pradesh, and Jammu & Kashmir.

Answer: (A) Paddy

Explanation:
Large stretches of farmland were submerged, and paddy crops in particular suffered heavy losses, alongside damage to poultry and dairy farms.

Answer: (A) October to December

Explanation:
This season follows the withdrawal of the summer monsoon and is marked by generally cloudless skies in north-western India during October and November.

Answer: (A) By the direction from which they originate

Explanation:
A westerly, for instance, is a wind coming from the west rather than one heading westward — naming follows the wind's source direction, not its destination.

Answer: (A) Fog

Explanation:
Precipitation in the chapter specifically covers drizzle, rain, snow, sleet, and hail — moisture that falls to the ground due to gravity. Fog, though listed among tropospheric weather events like rainfall and hail, is not classified as precipitation.

Answer: (A) Air is densest near the surface and thins out quickly with altitude

Explanation:
Since air density is greatest close to the ground and decreases going upward, the weight of air pressing down — and therefore pressure — also drops quickly with increasing altitude.

Answer: (A) Temperature, precipitation, humidity, wind, and atmospheric pressure

Explanation:
• Temperature affects heat and cold across seasons
• Precipitation and humidity relate to moisture in the air
• Wind moves air between pressure zones
• Atmospheric pressure ties all these elements together, influencing how weather unfolds at a place

Answer: (A) Cold air becomes heavy and sinks towards the ground

Explanation:
Since cool air is denser than warm air, it sinks downward, piling up near the surface and creating a zone of high pressure — the opposite of what happens when warm air rises and forms a low-pressure area.