UPSC Prelims Geography Archives - UPSC SHORT NOTES https://upscshortnotes.com/category/upsc-prelims-geography/ Thu, 05 Mar 2026 10:11:42 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 Q. The weight of an object at the poles is greater than at the equator. This is because https://upscshortnotes.com/q-the-weight-of-an-object-at-the-poles-is-greater-than-at-the-equator-this-is-because/?utm_source=rss&utm_medium=rss&utm_campaign=q-the-weight-of-an-object-at-the-poles-is-greater-than-at-the-equator-this-is-because Thu, 05 Mar 2026 10:09:42 +0000 https://upscshortnotes.com/?p=270 Q. The weight of an object at the poles is greater than at the equator. This is because (UPSC Prelims/1979) […]

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Q. The weight of an object at the poles is greater than at the equator. This is because (UPSC Prelims/1979)
(a) Of the shape of the earth
(b) The attraction of the moon is maximum at the earth’s surface
(c) The attraction of the sun is maximum at the earth’s surface
(d) Gravitational pull is more at the poles

Correct Answer: (a) Of the shape of the earth
Why option (a) is correct?
• Earth is an oblate spheroid (flattened at poles, bulged at equator)
• Radius of Earth is smaller at poles than at equator
• Gravitational acceleration (g) is inversely proportional to square of radius
• Smaller radius at poles → greater value of g → greater weight

Role of Earth’s Rotation
• Centrifugal force is maximum at the equator
• Centrifugal force is zero at the poles
• Centrifugal force reduces effective gravity at equator

Why other options are incorrect?
• Moon’s attraction is negligible compared to Earth’s gravity
• Sun’s attraction does not cause daily weight variation
• Gravitational pull being more at poles is an effect, not the root cause

Key Formula
• Weight (W) = m × g
• Mass remains constant; g varies with location

Comparison: Poles vs Equator
• Poles → Minimum radius, zero centrifugal force, maximum weight
• Equator → Maximum radius, maximum centrifugal force, minimum weight

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]]> Q. When a man circles round the earth in a satellite, then https://upscshortnotes.com/q-when-a-man-circles-round-the-earth-in-a-satellite-then/?utm_source=rss&utm_medium=rss&utm_campaign=q-when-a-man-circles-round-the-earth-in-a-satellite-then Thu, 05 Mar 2026 10:02:00 +0000 https://upscshortnotes.com/?p=268 Q. When a man circles round the earth in a satellite, then (UPSC Prelims 1979) (a) His mass becomes zero […]

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Q. When a man circles round the earth in a satellite, then (UPSC Prelims 1979)
(a) His mass becomes zero but weight remains constant
(b) Mass remains constant but weight becomes zero
(c) Both mass and weight remain constant
(d) Both mass and weight remain zero

Correct Answer: (b) Mass remains constant but weight becomes zero
Why option (b) is correct?
• Mass is the amount of matter → does not change anywhere
• Weight = m × g → depends on gravitational acceleration (g)
• In a satellite, the astronaut and satellite are in continuous free fall around the Earth
• Normal reaction becomes zero → apparent weight = 0 (Weightlessness)
👉 Gravity is not zero in orbit; the astronaut only appears weightless

Key Concepts You Must Know

1. Mass vs Weight
• Mass → Independent of location, SI unit: kg
• Weight → Depends on gravity, SI unit: Newton (N)
• In space → Mass same, Weight zero (apparent)

2. What is Weightlessness?
• Condition when apparent weight becomes zero
• Occurs when no supporting force acts on the body
• Seen in satellites, free-falling lift, space stations

3. Why do astronauts float?
• Satellite has tangential (orbital) velocity
• Gravity provides centripetal force
• Astronaut and satellite fall together → no contact force → floating effect

4. Is gravity absent in space?
❌ No
• Gravity decreases with height but never becomes zero
• At satellite height, gravity is about 90% of Earth’s surface value

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]]> Q. Solar eclipse occurs when (UPSC Prelims 1979) https://upscshortnotes.com/q-solar-eclipse-occurs-when-upsc-prelims-1979/?utm_source=rss&utm_medium=rss&utm_campaign=q-solar-eclipse-occurs-when-upsc-prelims-1979 Thu, 05 Mar 2026 09:36:53 +0000 https://upscshortnotes.com/?p=263 Q. Solar eclipse occurs when (UPSC Prelims 1979) (a) Earth comes between Sun and Moon (b) Moon is at right […]

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Q. Solar eclipse occurs when (UPSC Prelims 1979)
(a) Earth comes between Sun and Moon
(b) Moon is at right angle to the Earth
(c) Moon comes between Sun and Earth
(d) Sun comes between Moon and Earth

Correct Answer: (c) Moon comes between Sun and Earth
What is a Solar Eclipse?
A solar eclipse occurs when the Moon moves between the Sun and the Earth,
blocking the Sun’s light either partially or totally for a short time.

Basic Alignment (Very Important)
Sun – Moon – Earth (in a straight line)
This alignment is called Syzygy.

When does a Solar Eclipse occur?
• Only on a New Moon day (Amavasya)
• When the Moon is near one of the lunar nodes

Why not every New Moon causes an eclipse?
• Moon’s orbit is tilted about 5° to Earth’s orbit

Types of Solar Eclipse
• Total Solar Eclipse → Moon completely covers the Sun (Umbra)
• Partial Solar Eclipse → Sun partly covered (Penumbra)
• Annular Solar Eclipse → Ring of fire appearance (Antumbra)
• Hybrid Solar Eclipse → Total at some places, annular at others

Shadow Regions
• Umbra → Total eclipse
• Penumbra → Partial eclipse
• Antumbra → Annular eclipse

Duration & Visibility
• Lasts only a few minutes
• Visible from limited areas of Earth

Solar vs Lunar Eclipse
Solar Eclipse → New Moon, unsafe to see directly
Lunar Eclipse → Full Moon, safe to view

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