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GATE 2026 CE (CE2) – Question 41

Geomatics Engineering · Distance and angle measurement, levelling, traversing, triangulation, total station · 2 marks · Multiple choice

For the traverse given below, the benchmark is at ground point L. The Reduced Level (RL) of L is 150.000 m. The direction of the traverse is from L to N. The readings on levelling staff using the same levelling instrument kept at Stations S1 and S2 during the traversing are shown in the figure.

[Figure: A levelling traverse from L through M to N. The instrument at S1 reads 1.5 m on the staff at L and 2.0 m on the staff at M. The instrument at S2 reads 1.8 m on the staff at M and 1.0 m on the staff at N.]

Column 1Column 2
(I) Sum of Back Sights(P) 3.300 m
(II) Sum of Fore Sights(Q) 2.500 m
(III) RL of Point N(R) 150.300 m
(S) 3.000 m
(T) 150.500 m

Matching the information given under Column 1 and Column 2, which one of the following options is CORRECT?

Diagram for GATE 2026 CE (CE2) question 41
  1. (I) – (P) ; (II) – (S) ; (III) – (R)
  2. (I) – (P) ; (II) – (Q) ; (III) – (R)
  3. (I) – (S) ; (II) – (P) ; (III) – (T)
  4. (I) – (S) ; (II) – (Q) ; (III) – (T)

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Correct answer: (A) (I) – (P) ; (II) – (S) ; (III) – (R)

Explanation

The traverse runs from L to N. From S1 the staff at L is read first (back sight, 1.5 m) and the staff at M next (fore sight, 2.0 m). From S2 the staff at M is read first (back sight, 1.8 m) and the staff at N next (fore sight, 1.0 m). Sum of back sights = 1.5 + 1.8 = 3.300 m. Sum of fore sights = 2.0 + 1.0 = 3.000 m. RL of N = 150.000 + 3.300 - 3.000 = 150.300 m. That gives (I)-(P), (II)-(S) and (III)-(R).