The correct option is
1 and 3 only
.Explanation
The Indian Standard Meridian determines the Indian Standard Time (IST). It is a specific longitude selected to establish a uniform time zone across the country, eliminating the confusion arising from local time differences caused by India's longitudinal extent.
Statement 1 is Correct:
By international agreement and general convention, the standard meridians of countries are selected in multiples of 7°30' of longitude. This corresponds to a time difference of 30 minutes relative to Greenwich Mean Time (GMT). India's selected meridian, 82°30', is exactly divisible by 7°30'.
Statement 2 is Incorrect:
India is located in the Eastern Hemisphere relative to the Prime Meridian. Therefore, the Indian Standard Meridian corresponds to 82°30' E (East), not West. A longitude of 82°30' W would pass through the Western Hemisphere (e.g., near the Americas).
Statement 3 is Correct:
The primary purpose of adopting a single standard meridian is to ensure administrative and civil uniformity. The local time at 82°30' E is applied as the standard time for the entire country, ensuring that watches in all parts of India-from Gujarat to Arunachal Pradesh-show the same time despite the actual difference in solar time.
Key Takeaway:
The Indian Standard Meridian is 82°30' E. It passes through Mirzapur (Uttar Pradesh) and is 5 hours and 30 minutes ahead of GMT. It traverses five states: Uttar Pradesh, Madhya Pradesh, Chhattisgarh, Odisha, and Andhra Pradesh.