Paper II · Part B — Geography

The Earth: Latitudes, Longitudes and Movements

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Build exam-ready understanding by connecting the core idea, formulas or facts, worked example and previous NDA questions. Focus on why each rule works, then test it under timed conditions.

Concept

The Earth is an oblate spheroid. Latitudes (parallels) and longitudes (meridians) form a grid used to locate any point and to reckon time. The Earth rotates on its axis (causing day and night) and revolves around the Sun (causing seasons).

Longitude is directly linked to local time.

Key Points & Formulas

Equator = 0° latitude; Prime Meridian = 0° longitude (through Greenwich).
Earth rotates 15° of longitude per hour; the International Date Line is roughly 180°.
Tropic of Cancer 23½°N, Tropic of Capricorn 23½°S.
Indian Standard Time is based on 82½°E.

Worked Example

Q. If the local time at a place is ahead of Greenwich by 5 hours 30 minutes, find its longitude.

Earth turns 15° per hour ⇒ 1 hour = 15°, so 5.5 h = 82.5°.

Time is ahead of GMT ⇒ the place is east.

Longitude = 82½° E (this is India's standard meridian).

Common traps

Reading the prompt too quickly and missing a qualifier.
Memorising the result without checking when it applies.
Skipping units, signs, chronology or the final reasonableness check.

NDA shortcuts

State the governing rule before substituting values.
Eliminate impossible options before doing full calculation.

One-screen revision sheet

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Core definition
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Past-paper bank

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5 NDA questions

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Question 1

NDA I 2026

Consider the following statements in case of terrestrial planets:

I. Mercury, Venus, Earth and Mars are terrestrial planets having low densities as compared to other planets.

II. They lie between the Sun and the belt of asteroids.

III. Their lower gravity can hold the escaping gases.

Which of the statements given above is/are correct?

Question 2

NDA II 2025

Which of the following statements with reference to shadow zones in an event of an earthquake is/are correct?

1. Zone between 105° and 145° from epicentre was identified as the shadow zone for both P-waves and S-waves

2. The shadow zone of P-waves is much larger than that of the S-waves

Select the answer using the code given below:

Question 3

NDA I 2024

Which of the following statements regarding Earth's internal structure is/are correct?
1. The oceanic crust is heavier than the continental crust.
2. Most of the Earth's internal heat is contained within the mantle.
3. Large convective cells in the crust circulate heat and drive plate-tectonic processes.
Select the answer using the code given below:

Question 4

NDA I 2024

Which of the following statements regarding earthquakes is/are correct?
1. The point on the Earth’s surface directly above the focus is called the epicentre of the earthquake.
2. Earthquakes generate Primary and Secondary waves that radiate outward from the earthquake focus.
3. Deep-focus earthquakes are likely to cause more damage than shallow-focus earthquakes.
Select the answer using the code given below:

Question 5

NDA I 2023

Which one of the following is the correct sequence of arrangement of the given planets in descending order of their density (in gm/cm $^3$ )?

Continue in Test Module Rocks and their Classification →