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Correct Answer: Option (C) — 18.30 hrs
Concept & Option Breakdown
Standard Reference Verified• IST meridian is 82°30' E; International Date Line (IDL) is at 180°. • Longitude difference = 180° - 82°30' = 97°30' = 6.5 hours (6 hours 30 min). • Under normal rotation (West to East), IST is 6.5 hours behind IDL in terms of solar noon, but in the reversed scenario (East to West rotation), eastern longitudes lag behind the IDL. • When it is 12:00 noon at IDL, IST will lag by 6 hours 30 minutes, or alternatively receive sunrise later: 12:00 + 6:30 = 18:30 hrs.
Standard difference between 82.5°E and 180° is 6.5 hours. Reversing direction reverses the time relation: 12:00 + 6.5 hrs = 18:30 hrs.
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