GATE 2023 Surveying Quiz 58

In trigonometric levelling which of the following instrument is used?

To find the reduced level of a roof slack of building, staff readings curve taken from a set-up of the levelling instrument. The readings were 1.050 m with staff on the BM and 2.300m with staff below the roof slab and inverted. Taking the reduced level of BM as 135.15m, the reduced level of the roof slab will be_________.

An instrument was setup at A and the angle of depression to a vane 2 m above the foot of the staff held at B was 5°. The horizontal distance between A & B was known to be 3000 metres. Determine the reduced level of the staff station B if the staff reading on benchmark located at 3000 m is 2.865 metres. Take RL of benchmark = 350.205 metres.

The combined correction for curvature and refraction can be given as:-

Two pegs ‘P’ and ‘Q’ were fixed on opposite banks of a river and the following measurements were made during testing a leveling instrument.

If the reduced level of station ‘Q’ is 106.500 m, the reduced level of station ‘P’ is ____ m. (Upto 2 decimal places. Neglect earth’s curvature and refraction correction)

A top of tower is observed from the exact two opposite banks of river, the bottom of tower & height of instruments on both side of river is at same level, height of tower is 30m, and angle made by nearest & farthest instrument is 45° & 31°, find the width of the river.