Globe Latitude and longitude - Chapter Wise CBSE Solved Question and Answer Based On NCERT
Long Q&A:
Q1: Why is it necessary to have standard time? Also define Indian Standard Time (IST)
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Ans:
It is necessary to have a standard time because:
a. Different meridians have different time, which makes it difficult to prepare a time table for trains and flights.
b. It helps to maintain uniformity of time throughout the country. Indian Standard Time: In India, the longitude of 82o 30'E is treated as the standard meridian and the local time at this meridian is taken as the standard time for the whole country. It is known as Indian Standard Time (IST).
Q2: Which meridian is taken as a standard meridian for India and why?
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Ans:
In India, 82° 30' E is taken as a standard meridian because for every 1° longitude time difference is 4 minutes. India’s total longitudinal extent is 30° (97°E-67°E=30°E). So, total time difference is 30*4=120 minutes or 2 hours, that means the time difference between Gujarat and Arunachal Pradesh would be 2 hrs. To avoid such confusion and to have same time all over the country, we have taken a standard meridian.
