If parallels are drawn at an interval of one degree, how many are there in all, including the equator?
- A.180
- B.181
- C.360
- D.361
Correct answer
Explanation
The correct answer is B, 181. There are 90 parallels in the northern hemisphere, 90 in the southern hemisphere and the equator itself, which belongs to neither, making 181 in all. Note that the poles are points rather than circles, although they are counted as the ninetieth parallel in each hemisphere.
Option A, 180, is what you get by forgetting the equator, and it is the commonest mistake in this question. Option C, 360, is the number of meridians at one degree intervals, 180 to the east and 180 to the west of the Prime Meridian, and option D, 361, mixes the two counts together. Keep the pair straight: 181 parallels and 360 meridians. The reason for the difference is that a meridian runs only from pole to pole and its opposite half is counted separately, while a parallel is a complete circle on its own.
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 →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
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A great circle is one whose plane passes through the centre of the sphere and which therefore divides it into two equal halves.
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 →