Test: Latitudes & Longitudes (UPSC Level) - UPSC MCQ

Let's evaluate each statement:

1. The equatorial radius of Earth is larger than its polar radius due to the planet's rotation.

- This statement is correct. The Earth's rotation causes it to bulge slightly at the equator, making the equatorial radius larger than the polar radius.

2. The Earth's equatorial radius is approximately 6,356 km.

- This statement is incorrect. The Earth's equatorial radius is approximately 6,378 km, not 6,356 km. The value 6,356 km actually refers to the polar radius.

3. The difference between Earth's equatorial and polar radii is about 22 km.

- This statement is correct. The difference between the equatorial radius (6,378 km) and the polar radius (6,356 km) is indeed about 22 km.

Both statements are correct in their respective descriptions of the Torrid Zone and the Frigid Zones. Statement-I correctly explains that the Torrid Zone receives maximum heat due to the direct overhead sun between the Tropics of Cancer and Capricorn. Statement-II accurately describes the Frigid Zones, highlighting their cold temperatures resulting from the sun's low position in the sky. The directness of the sun's rays significantly affects the temperature in these regions, making Statement-II an explanation of the conditions presented in Statement-I. Hence, Option A is the correct choice.

The Tropic of Cancer, located at 23½° north of the equator, marks the northern boundary of the Torrid Zone and the beginning of the Temperate Zone in the Northern Hemisphere. This latitude signifies where the sun is directly overhead at noon during the summer solstice in the Northern Hemisphere. This transition zone between the Torrid and Temperate Zones experiences varying angles of sunlight throughout the year, leading to distinct climate characteristics.

The Equator is indeed an imaginary line that divides the Earth into two equal parts, the Northern Hemisphere and the Southern Hemisphere. Additionally, the statement about the North and South latitudes correctly explains how these parallels are indicated on the Earth. Therefore, Option A is correct. The Equator plays a crucial role in geography and understanding the global division, while the concept of latitudes further helps in specifying locations on the Earth's surface.

Standard Time is crucial to maintain uniformity in timekeeping across different regions globally. It helps in establishing a common reference point for coordinating activities, such as transportation schedules, communication, and international business operations. Without Standard Time, the discrepancies in local times across various meridians would lead to confusion and inefficiencies in everyday life. Thus, the concept of Standard Time simplifies time management and facilitates smooth interactions on a worldwide scale.

1. Equator - 90 degrees latitude: This pair is incorrectly matched. The Equator is at 0 degrees latitude, not 90 degrees. It is the baseline from which latitude is measured, dividing the Earth into the Northern and Southern Hemispheres.

2. North Pole - 90 degrees north latitude: This pair is correctly matched. The North Pole is indeed at 90 degrees north latitude, which is the northernmost point on Earth.

3. South Pole - 90 degrees south latitude: This pair is correctly matched. The South Pole is at 90 degrees south latitude, marking the southernmost point on Earth.

4. Prime Meridian - 0 degrees longitude: This pair is correctly matched. The Prime Meridian is the line of 0 degrees longitude, passing through Greenwich, England, and serves as the starting point for measuring longitude east and west around the Earth.

Thus, pairs 2, 3, and 4 are correctly matched.

The Equator serves as the line of 0 degrees latitude on Earth and plays a crucial role in dividing the planet into the Northern Hemisphere and the Southern Hemisphere. This imaginary line is equidistant from the North Pole and the South Pole, providing a reference point for understanding the Earth's hemispheric divisions. It also helps in establishing other latitudinal measurements on the globe, such as the Tropic of Cancer and the Tropic of Capricorn.

To determine the correct statements, let's analyze each one:

Statement 1: "The earth rotates 360° in 24 hours, which means it rotates 15° in one hour."
- This statement is correct. The earth completes one full rotation of 360° in 24 hours. Therefore, it rotates 15° every hour (360°/24 hours = 15° per hour).

Statement 2: "The Indian Standard Time (IST) is based on the longitude 82° 30'E."
- This statement is correct. The Indian Standard Time is indeed based on the meridian at 82° 30'E, which is used as the reference for the entire country.

Statement 3: "The time difference between Greenwich Mean Time (GMT) and Indian Standard Time (IST) is 6 hours."
- This statement is incorrect. The actual time difference between GMT and IST is 5 hours and 30 minutes, not 6 hours. IST is ahead of GMT by this amount due to the position of the standard meridian (82° 30'E).

Based on this analysis, only statements 1 and 2 are correct, making Option B: 1 and 2 Only the accurate answer.

1. Statement 1: The Tropic of Cancer is indeed located at 23½° North latitude. This is a well-known geographical fact, and it marks one of the major circles of latitude on Earth. Therefore, this statement is correct.

2. Statement 2: The Antarctic Circle is correctly identified as being situated at 66½° South latitude. This is an important parallel of latitude that marks the southernmost point at which the sun can be seen on the winter solstice in the Southern Hemisphere. Thus, this statement is also correct.

3. Statement 3: The Prime Meridian does not divide the Earth into Northern and Southern Hemispheres; rather, it divides the Earth into Eastern and Western Hemispheres. The division into Northern and Southern Hemispheres is done by the Equator. Hence, this statement is incorrect.

Based on the evaluation of each statement, only statements 1 and 2 are correct. Therefore, the correct answer is Option B: 1 and 2 Only.

Answer: B: Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I

• Statement-I is correct because the movement of the Earth, Moon, and planets has historically been used to measure time, for example, through the solar day (based on Earth's rotation), lunar months (based on the moon's orbit around Earth), and planetary movements. These movements form the basis of various timekeeping systems.
• Statement-II is also correct because local time varies based on the longitude (meridian) of different places. For example, places on different meridians (longitudes) will experience daylight and darkness at different times, leading to different local times.