5 hours 30 minutes
Explanation
Time zones are determined based on longitudes. The Earth rotates 360° in approximately 24 hours, which means it covers 15° of longitude per hour or 1° every 4 minutes. Places east of the Prime Meridian (Greenwich, 0°) are ahead in time, while places to the west are behind.
Detailed Calculation:
- The Indian Standard Time (IST) is calculated based on the Standard Meridian of India, which is 82°30' E (82.5° East) longitude.
- Greenwich Mean Time (GMT) is based on the Prime Meridian at 0° longitude.
- The longitudinal difference between IST and GMT is 82.5°.
- Since 1° longitude corresponds to a time difference of 4 minutes:
Calculation: 82.5 × 4 minutes = 330 minutes. - Converting 330 minutes into hours:
330 ÷ 60 = 5 hours and 30 minutes. - Because India is located east of Greenwich, IST is ahead of GMT.
Key Takeaway:
Indian Standard Time (IST) corresponds to longitude 82°30' E, making it 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT).