Which is the only parallel of latitude that is a great circle?
- A.The equator
- B.The Tropic of Cancer
- C.The Arctic Circle
- D.The Tropic of Capricorn
Correct answer
Explanation
The correct answer is A, the equator. A great circle is one whose plane passes through the centre of the sphere and which therefore divides it into two equal halves. Among the parallels only the equator satisfies this, which is why it separates the northern and southern hemispheres and is the longest parallel of all.
Option B, the Tropic of Cancer, and option D, the Tropic of Capricorn, lie 23.5 degrees away from the equator, so their planes are offset from the centre and the circles they form are smaller. Option C, the Arctic Circle, at 66.5 degrees north, is smaller still, because parallels shrink steadily towards the poles. Meridians behave differently: every meridian and its opposite meridian together make a full great circle, which is why the shortest air route between two distant cities follows a great circle and often looks curved on a flat map.
Read the full article: Latitudes, Longitudes and Time: Grid, IST and Date Line
Practice Questions
View allIndian Standard Time is based on which meridian?
- A.75 degrees east
- B.82 degrees 30 minutes east
- C.88 degrees 30 minutes east
- D.90 degrees east
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This meridian passes near Mirzapur in Uttar Pradesh and runs roughly through the middle of the country, so it was adopted as the standard meridian of India.
Read the full explanation →One degree of longitude corresponds to how much difference in time?
- A.One minute
- B.Four minutes
- C.Fifteen minutes
- D.One hour
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The earth completes one rotation of 360 degrees in 24 hours, that is 1,440 minutes, and dividing 1,440 by 360 gives four minutes for every degree of longitude.
Read the full explanation →The Tropic of Cancer does not pass through which of the following Indian states?
- A.Jharkhand
- B.Chhattisgarh
- C.Odisha
- D.Tripura
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The Tropic of Cancer passes through eight states, namely Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram.
Read the full explanation →The Prime Meridian passes through which place?
- A.Paris
- B.Greenwich
- C.Rome
- D.Washington
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The meridian running through it was accepted as the zero meridian, from which all longitudes are counted east and west, and its local time is Greenwich Mean Time, the reference for the world's standard times.
Read the full explanation →The Arctic Circle is drawn at which latitude?
- A.23.5 degrees north
- B.45 degrees north
- C.66.5 degrees north
- D.90 degrees north
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The Arctic Circle marks the latitude beyond which the sun stays above the horizon for the whole of at least one day in midsummer and below it for the whole of at least one day in midwinter, the phenomenon known as the midnight sun and the polar night.
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