A method of differential levelling is used in order to find the difference in elevation between two points when

Overturning of vehicles on a curve can be avoided by using

Which of the following is the accurate method for plotting traverse area?

In a theodolite the line of collimation is

One mile equals to

Negative errors are causes in chain, when its length is

In reciprocal levelling, the error which is not completely eliminated, is due to

While surveying a plot of land by Plane tabling, the field observations

If 'n' is the number of sides, then the total sum of exterior angles of a closed traverse should be