Levelling MCQ with answer and solution

Concept

Levelling procedure for instrument change points

Formula

NONE

Step-by-step solution

1. Standard leveling procedure requires establishing the height of the instrument by taking a backsight on a known reference point. 2. The instrument is then turned to observe a foresight on the change point before being moved to the next station setup. 3. Therefore, taking a backsight on a known point, moving the instrument, and taking a foresight on the change point represents the correct sequence. Answer: D

Explanation

When transferring leveling operations to a new setup, a backsight reading is first taken on a known benchmark or reference point, followed by a foresight reading on the selected change point. After relocating and leveling the instrument at the new position, a new backsight reading must be taken on that same change point to establish the new height of instrument. Therefore, option D correctly describes this standard sequence of levelling operations.

Why the other options are wrong

A) Foresight cannot be taken before establishing a Backsight on the known point. B) Backsight must be taken on a known point before moving the instrument, not directly on the change point first.

Shortcut

Change Point order: BS on known point -> FS on CP -> Move setup -> BS on CP.

Common mistake

Selecting option C or A by confusing the sequence of taking a Foresight on the Change Point before moving the instrument and taking a Backsight from the new setup.