Consider the following lines of Longitude and Latitude:
1.Prime Meridian
2.Tropic of Cancer
3.Equator
Which of the above lines is/are a Great Circle?
- AOption (a)
1, 2 and 3
- BOption (b)
1 and 2 only
- COption (c)
1 and 3 only
- DOption (d)
3 only
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Correct answer
1 and 3 only
Why this answer is correct
The correct answer is "1 and 3 only".
Key Points
- A Great Circle is the largest possible circle that can be drawn on a sphere, whose plane passes through the center of the Earth.
- Equator is a Great Circle because it divides the Earth into two equal halves (Northern Hemisphere and Southern Hemisphere). Hence, statement 3 is correct.
- Prime Meridian along with its opposite meridian (180° longitude) forms a Great Circle passing through the poles and the Earth's center. Hence, statement 1 is correct.
- Tropic of Cancer is a small circle (parallel of latitude at 23.5° North) and does not pass through the center of the Earth. Hence, statement 2 is incorrect.
- Hence, the correct answer is "1 and 3 only".
Additional Information
- Latitude: Imaginary horizontal lines measured in degrees north or south of the Equator (0°).
- Longitude: Imaginary vertical lines measured in degrees east or west of the Prime Meridian (0°), which passes through Greenwich, London.
- Great Circles Importance: They represent the shortest distance between two points on the Earth's surface and are used in aviation and navigation.
- Small Circles: All parallels except the Equator (like Tropic of Cancer, Tropic of Capricorn, Arctic Circle) are small circles.
- Key Values: Equator = 0° latitude, Tropic of Cancer = 23.5° N, Tropic of Capricorn = 23.5° S.
Important Points
- All longitudes are parts of great circles when considered with their opposite meridian.
- The Equator is the only latitude that is a Great Circle; all other latitudes are small circles.