CBSE Class 7 Social Science Chapter 02 Understanding The Weather MCQs Set 01

Answer: (A) Because the cold air there contracts

Explanation:
Cold air contracts, which reduces the height of the troposphere near the poles, while warmer air in the tropics expands and makes the layer thicker there.

Answer: (B) A word like 'chilly' means different things to people used to different climates

Explanation:
Krishnan finds it hard to make Amir understand exactly how cold Chennai feels, since what feels chilly to someone from Chennai might feel pleasant to someone from Kashmir. This shows why a common, agreed way of measuring temperature is necessary.

Answer: (C) Altitude

Explanation:
The five elements of weather are temperature, precipitation, atmospheric pressure, wind and humidity; altitude is discussed only as a factor affecting pressure, not as a weather element itself.

Answer: (C) The depth of rainwater that fell over that area

Explanation:
The funnel channels rainwater into a measuring tube, and the height the water reaches on the scale is read as the depth of rainfall received in that area — so a 5 mm reading means 5 mm of rain fell.

Answer: (B) Lower atmospheric pressure at altitude means less oxygen reaches the lungs

Explanation:
As altitude increases, the air thins and pressure drops, so less oxygen is available for the lungs — forcing the body to work harder, which can cause breathlessness, dizziness or tiredness.

Answer: (A) Atmospheric pressure has fallen sharply and may lead to a storm or cyclone

Explanation:
A sudden, dramatic drop in atmospheric pressure over the plains or coast is termed a depression, and this can sometimes intensify into a storm or cyclone.

Answer: (B) Pressure decreases noticeably as altitude increases

Explanation:
The steep drop from 1013 mb at sea level to about 650 mb at over 5600 metres shows how sharply atmospheric pressure falls with increasing height — which is why people need time to acclimatise at such altitudes.

Answer: (B) From high-pressure areas to low-pressure areas

Explanation:
Wind is described simply as air moving from zones of high pressure toward zones of low pressure, which is why pressure differences drive the wind's speed and direction.

Answer: (B) Showing pilots the direction of the wind during landing and takeoff

Explanation:
Since it is essentially a large wind vane, the wind sock fills with air and points in the wind's direction, letting pilots judge conditions as planes land or take off.

Answer: (B) By counting how many times its rotating cups spin in a given time

Explanation:
Its cups spin faster in stronger winds, and a meter counts the number of rotations over a fixed period, converting this into a speed reading in kilometres per hour.

Answer: (B) The air is completely saturated with water vapour

Explanation:
The relative humidity scale runs from 0%, representing air with no moisture (a purely theoretical condition), up to 100%, which means the air is holding all the water vapour it possibly can.

Answer: (B) Because a dry environment is often needed to protect exhibits from damage

Explanation:
Museums monitor humidity to maintain dry conditions, which helps preserve delicate exhibits over time.

Answer: (B) Ants shifting eggs, frogs croaking, and pine cones opening or closing

Explanation:
Long before instruments existed, people read signs such as ants carrying their eggs to higher ground, frogs croaking loudly, and pine cones reacting to humidity by opening or closing, as indicators of approaching rain.

Answer: (B) To give early warning of changing weather conditions in that high-risk area

Explanation:
Placed by the National Disaster Management Authority, this AWS continuously gathers weather data without needing a person present, helping provide advance warning of conditions near the glacial lake.

Answer: (A) The condition of the atmosphere at a specific place and time

Explanation:
Weather refers to the immediate, ever-changing state of the atmosphere at a given place and moment, unlike climate, which describes long-term patterns and is discussed in the next chapter.

Answer: (B) The temperature of the immediate surroundings

Explanation:
The glossary explains 'ambient' as relating to one's immediate surroundings, so an ambient thermometer simply records the current surrounding air temperature rather than extremes or body heat.

Answer: (B) 1875; that rain originates from the sun

Explanation:
Set up in 1875, the IMD's motto 'ādityāt jāyate vriṣhti' means 'from the sun arises rain,' a line drawn from the ancient text Manusmriti connecting sunlight, rain, food and life.

Answer: (B) By adding the maximum and minimum temperatures and dividing by two

Explanation:
Mean daily temperature is simply the sum of the day's maximum and minimum readings divided by two, giving a quick average for that day.

Answer: (C) Range of temperature

Explanation:
Subtracting the day's lowest temperature from its highest gives the range of temperature, one of the two temperature statistics described alongside the mean.

Answer: (B) Its tail gets pushed by the wind, causing the pointer to turn towards the wind's direction

Explanation:
A wind vane has a pointer on one end and a tail on the other; the wind pushes against the tail, swinging the arm so the pointer faces into the wind and shows its direction — even a light breeze is enough to move it.

Answer: (B) It works without requiring people to take readings, using sensors instead

Explanation:
An AWS uses sensors to record temperature, humidity, wind, precipitation and pressure automatically. Because it needs no one physically present to take readings, it is especially useful in remote places like the glacial lake site set up in Sikkim.
• Provides continuous, timely data
• Supports agriculture, aviation and disaster monitoring
• Reduces dependence on human observers in hard-to-reach areas

Answer: (D) Immediate action is required due to severe weather

Explanation:
The colour scale runs from green (no warning) through yellow (watch) and orange (alert) to red, which is the most serious category, meaning people need to take action right away.

Answer: (B) It helps them guess which direction rain might be approaching from

Explanation:
Since wind carries moisture and weather systems with it, farmers use its direction as a practical clue to anticipate where incoming rain is likely to come from, helping them plan their work.

Answer: (A) Allow the body time to adjust to lower oxygen and pressure conditions

Explanation:
At high altitudes such as Khardung La, where pressure can drop to around 650 millibars, the body needs time to adapt to reduced oxygen; pausing during ascent helps prevent breathlessness, dizziness and fatigue.

Answer: (B) Everyday observations can reveal changes in temperature

Explanation:
Alongside snow melting in warmth and coconut oil solidifying in winter, the slow setting of curd in cold weather is offered as a simple, everyday sign that helps people sense temperature changes even without a thermometer.