As applied to staff readings, the corrections for curvature and refraction are respectively The above table shows a part of a level field book. The value of X should be

Related MCQs

• When the effect of refraction is taken into account in levelling, the true staff reading is obtained by subtracting the correction for refraction from the observed staff reading.
• When a staff is sighted through the telescope, a certain length of staff is intercepted by the stadia lines. The staff intercept varies with the distance at which the staff is held.
• The method of finding out the difference in elevation between two points for eliminating the effect of curvature and refraction, is
• Combined correction for curvature and refraction for 800 m distance is……
• In levelling, the correction for combined curvature and refraction (in metres) is equal to
• In levelling, the correction for curvature (in metres) is equal, where D = Distance from the level to the staff reading in kilometres.
• If the horizontal distance between the staff point and the point of observation is d, then the error due to curvature of earth is proportional to
• When the effect of curvature is taken into account in levelling, the true staff reading is obtained by
• In plane table surveying, field work is recorded in a field book to be plotted afterwards.
• It is required to find the difference in elevation between two points A and B. During levelling, it is found that the staff reading at B is more than the staff reading at A. It indicates that the point A is