The imaginary line passing through the intersection of cross hairs and the optical centre of the objective, is known as ............

When the whole circle bearing of a traverse line is between 90° and 180° then ............

The multiplying constant for the tacheometer is, generally, kept as ............

The main difference between an optical square and prism square is ............

The image formed by the objective in the plane of cross hairs is ............

Metric chains are generally available in ............

Diurnal variation of magnetic declination is ............

In chain surveying tie lines are primarily provided ............

The limiting length of the offset is ............ when its perpendicular direction is set out by an eye.