GATE 2024 AG – Question 43
Leveling starts at RL53.85 m. A second benchmark has known RL85.45 m and is read as intermediate sight2.42 m. Cumulative backsights are50.28 m and foresights16.30 m up to this setup. If the survey closes on that second benchmark, find closure error magnitude in m.
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Correct answer: (B) 0.04
Explanation
The current instrument height is $53.85+50.28-16.30=87.83$ m. Subtract the second benchmark’s staff reading2.42 m to get observed RL85.41 m. Closure discrepancy is $85.41-85.45=-.04$ m, so the requested magnitude is **.04 m, B**. The final intermediate reading becomes the closing sight in this balance.