Section 4: Soil and Water Conservation Engineering
Surveying and Levelling
Subtopic: Instruments for surveying and levelling
Question Statement:
Line of sight through the leveling instrument is called
Options:
(A) Backsight
(B) Foresight
(C) Line of collimation
(D) Sight of collimation
Official Answer Key:
C
Step-by-Step Solution & Explanation
The 'line of sight' or 'line of collimation' is the imaginary line joining the optical centre of the objective lens to the intersection of the cross-hairs (and extended to the point observed), i.e., the actual sighting line through the instrument's telescope. 'Backsight' (A) and 'Foresight' (B) refer to specific staff readings taken along this line, not the line itself. (D) is not standard surveying terminology, so the correct term is (C).
Practice This in Real CBT Exam Interface
Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.