Civil Engineering - Advanced Surveying - Discussion
Discussion Forum : Advanced Surveying - Section 3 (Q.No. 19)
19.
With standard meridian as 82° 30' E the standard time at longitude 90° E is 8 h 30 m. The local mean time at the place will be
Discussion:
1 comments Page 1 of 1.
M Azeem Irshad said:
6 months ago
1: Find the Time Difference per Degree
The Earth rotates 360° in 24 hours, meaning:
Time difference per degree 24 hours/360
Time difference per degree 4 minutes per degree
2: Find the Longitude Difference:
The given longitude is 90° E, and the standard meridian is 82° 30' E.
Longitude difference 90−82.5 = 7.5 °.
3: Compute the Time Difference:
7.5 ×4 minutes per degree = 30 minutes.
Since 90° E is east of 82° 30' E, the local mean time (LMT) will be ahead of the standard time.
Hence,
LMT = Standard Time + Time Difference
LMT = 8 h 30 m +30 m =9 h 00 m
Answer:
The Local Mean Time (LMT) at 90° E is 9:00 AM.
The Earth rotates 360° in 24 hours, meaning:
Time difference per degree 24 hours/360
Time difference per degree 4 minutes per degree
2: Find the Longitude Difference:
The given longitude is 90° E, and the standard meridian is 82° 30' E.
Longitude difference 90−82.5 = 7.5 °.
3: Compute the Time Difference:
7.5 ×4 minutes per degree = 30 minutes.
Since 90° E is east of 82° 30' E, the local mean time (LMT) will be ahead of the standard time.
Hence,
LMT = Standard Time + Time Difference
LMT = 8 h 30 m +30 m =9 h 00 m
Answer:
The Local Mean Time (LMT) at 90° E is 9:00 AM.
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