The three consecutive readings taken from a level are $1.325\text{m}, 0.985\text{m},$ and $2.546\text{m}.$ If the instrument was shifted after the first reading, the rise or fall of the last point is.

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This question was previously asked in

JKSSB JE (Civil) Official Paper (Held On: 19 Nov, 2023)

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Answer 1

Explanation:

Given:

Three consecutive readings:
- 1.325 m (Backsight, BS)
- 0.985 m (Foresight, FS — before instrument shifting)
- 2.546 m (Foresight after shifting — becomes a new BS for next setup)
The instrument is shifted after the first reading (1.325 m), so:

Classification of Readings:

Now, to determine rise or fall, we compare the FS1 and BS2 (as they are from two different instrument stations).

Calculation:

$Rise or Fall = BS2 - FS1 = 2.546 - 0.985 = 1.561 m rise$