CBSE Class 9 Social Science Chapter 03 Atmosphere And Climate MCQs Set 01

Answer: (A) Nitrogen and oxygen

Explanation:
Nitrogen accounts for about 78 per cent and oxygen for around 21 per cent, making them by far the most abundant atmospheric gases, while carbon dioxide, argon and others exist only in trace amounts.

Answer: (B) It is largely free of clouds and weather disturbances

Explanation:
Flying conditions are smoother there because the stratosphere lacks the clouds and turbulent weather that occur in the troposphere below it, not because of oxygen levels or pressure.

Answer: (B) Temperature falls again with height

Explanation:
Temperature decreases with altitude only in two layers, the troposphere and the mesosphere, so after the warming trend of the stratosphere, the mesosphere brings another decline before the thermosphere heats up sharply.

Answer: (C) They escape into outer space due to weak gravity

Explanation:
Because gravitational pull is very weak at this outermost layer, light gases like helium and hydrogen are able to drift off into space instead of being held near the Earth.

Answer: (B) Our bodies push back with an equal internal pressure

Explanation:
Air presses on us from every direction, and the internal pressure within our bodies balances it out, cancelling the sensation of an external force.

Answer: (B) Weather describes short-term daily conditions, while climate is the average pattern over a long period like thirty years

Explanation:
Weather changes hour to hour or day to day, whereas climate reflects the typical weather conditions of a region built up over an extended stretch of time, usually thirty years or more.

Answer: (C) It is called rain

Explanation:
Rain is simply the name given to precipitation reaching the ground as liquid; it is the most frequent type and tends to bring down the temperature of a place.

Answer: (B) Warm air expands and rises, reducing pressure at the surface

Explanation:
Heated air becomes lighter and rises upward, and this rising motion leaves behind a region of lower pressure near the ground, which is typically linked with cloudy, wet conditions rather than clear skies.

Answer: (B) Sea breeze, because land heats up faster than the sea during the day, creating low pressure over land

Explanation:
During the day the land warms up more quickly than the sea, so a low-pressure area forms over land and pulls in cooler air from the sea — this local afternoon flow is the sea breeze.

Answer: (C) Season

Explanation:
The word comes from 'mausim', an Arabic term simply meaning season, referencing the seasonal reversal of wind direction that ancient sailors observed while travelling to India.

Answer: (B) The Indian landmass heats up faster than the ocean, creating low pressure that draws in moist sea winds

Explanation:
Because land heats up more rapidly than water in summer, a low-pressure zone forms over the subcontinent while the ocean stays relatively high-pressure; moist winds then flow from sea to land, bringing rain.

Answer: (C) Tamil Nadu, Andhra Pradesh, and parts of Karnataka

Explanation:
As these winter winds cross the Bay of Bengal they pick up moisture, which they then release as rainfall along India's south-eastern coast, making the north-east monsoon important for that particular region.

Answer: (C) Arthaśhāstra

Explanation:
Kauṭilya's Arthaśhāstra is credited with documenting systematic rainfall measurement methods that were applied practically to administrative tasks like revenue collection and disaster relief.

Answer: (A) 0.1 to 0.4 per cent

Explanation:
The chapter gives a narrow range of 0.1-0.4 per cent for water vapour content, noting that this small but variable amount is crucial for cloud formation and precipitation.

Answer: (A) The incoming solar energy received by the Earth

Explanation:
Insolation is defined as the solar energy intercepted by the Earth, and the text uses it to explain why temperatures fall as one moves from the equator toward the poles.

Answer: (A) Charged particles from the solar wind striking gases in the atmosphere near the magnetic poles

Explanation:
• Solar wind carries charged particles from the Sun
• These particles get channelled toward Earth's magnetic poles
• On meeting atmospheric gases, each gas glows a distinct colour, producing the aurora seen in the thermosphere

Answer: (B) Stratosphere

Explanation:
The layers are arranged in order as troposphere, stratosphere, mesosphere, thermosphere and exosphere, so the thermosphere directly follows the mesosphere, not the stratosphere or exosphere.

Answer: (A) It reflects radio waves sent from the Earth back towards the surface

Explanation:
Because the ionosphere sits within the thermosphere, radio waves transmitted upward from Earth bounce off this layer and return to the surface, which is why it supports long-distance radio transmission.

Answer: (A) Because the amount of insolation received decreases towards the poles

Explanation:
The chapter links this temperature pattern directly to insolation, which is highest at the equator and steadily declines toward higher latitudes.

Answer: (A) An astronomical division of the twelve months into six equal parts

Explanation:
Traditionally, each of the six Indian seasons spans about two months, based on splitting the twelve months of the year into six astronomical divisions, unlike the IMD's four-season classification.

Answer: (A) The temperature and pressure difference between land and sea at night is comparatively small

Explanation:
At night the land cools faster than the sea, but the resulting gap in temperature and pressure between the two is not very large, so the land breeze that forms moves gently rather than strongly.

Answer: (A) It records the onset date of the monsoon over central India and describes the path of monsoon clouds

Explanation:
Written around the 5th century CE, this literary work is cited as evidence that ancient Indians closely observed and documented the monsoon's arrival and movement, well before modern meteorology existed.

Answer: (A) To make the country 'Weather Ready' and 'Climate Smart' by improving forecasting across sectors

Explanation:
Mission Mausam is positioned as an effort to place India among global leaders in weather and climate science, with better observation and forecasting benefiting agriculture, disaster management, and rural development.

Answer: (A) Weak and old river embankments that failed to hold back rising water

Explanation:
Alongside natural causes like intense monsoon rain, the chapter points to deteriorating dhusi bandh embankments, construction too close to riverbanks, and silt build-up reducing river capacity as human contributions to the disaster's severity.

Answer: (A) The total greenhouse gases released into the atmosphere due to one's activities like energy use and travel

Explanation:
Carbon footprint covers emissions tied to everyday choices—transport, electricity use, water consumption, and waste—which is why the chapter's self-assessment activity scores habits in exactly these areas.