Civil Engineering MCQAE Level Civil Engineering
If the R.L. of a B.M. is 100.00 m, the backsight is 1.215 m and the foresight is 1.870 m, the R.L. of the forward station is
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Choose the correct answer
A
99.345 m
B
100.345 m
C
100.655 m
D
101.870 m
Correct Answer
A. 99.345 m
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Rise-and-fall method levelling: RL_new = RL_known + BS - FS, where BS = backsight (reading on known-RL staff) and FS = foresight (reading on unknown-RL staff). Height of Instrument (HI) method: HI = RL_known + BS; RL_new = HI - FS. Arithmetic check: sum(BS) - sum(FS) = Last RL - First RL. RL = 100 + 1.215 - 1.870 = 99.345 m.
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This MCQ belongs to WBPSC AE Previous Years Questions Series. Full tests include timed attempts, rank comparison and subject-wise analysis.