Section 4: Soil and Water Conservation Engineering
Surveying and Levelling
Subtopic: Types of levelling
Question Statement:
In a differential levelling survey, the Back Sight (BS) reading taken on a benchmark of Reduced Level (RL) $100.00\text{ m}$ is $1.850\text{ m}$. The Fore Sight (FS) reading on a target station $P$ is $0.650\text{ m}$. The Reduced Level (RL) of station $P$ in metres is ________ (round off to 2 decimal places).
Answer Key:
101.20
Step-by-Step Solution & Explanation
1. Height of Instrument ($HI$):
$HI = \text{RL}_{BM} + BS = 100.00 + 1.850 = 101.850\text{ m}$
2. Reduced Level of station $P$:
$\text{RL}_P = HI - FS = 101.850 - 0.650 = 101.20\text{ m}$