A ‘level line’ is a
A level line is the distance between 2 points on the level surface, which follows the curvature of the earth. Whereas the line of sight is the straight line perpendicular to the plumb line at the telescope.
The difference between a level line and a horizontal line is that
With the rise of temperature, the sensitivity of a bubble tube
With a rise in temperature the liquid expands. Hence the bubble shortens and consequently its sensitivity decreases.
As applied to staff readings, the corrections for curvature and refraction are respectively
Which of the following arithmetic checks can be applied in rise and fall method?
The correction for refraction as applied to staff reading is
where R is radius of earth
Correction due to refraction is approximately about 1/7th of correction due to earth curvature.
CR = 1/7 Cc
While doing levelling in undulating terrain, it is preferable to set the level on
Which of the following statements is incorrect?
Benchmark is established by
The curvature of the earth’s surface, is taken into account only if the extent of survey is more than
Geodetic Survey is the survey in which earth’s curvature is taken into account for calculation. It is generally done when area to be covered is more than 260 km2