A Theodolite is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are mainly used for surveying applications, and have been adapted for special purpose in areas such as Meteorology and Rocket launch technology. A modern theodolite consists of a movable telescope mounted within two perpendicular axes - the horizontal (or) trunnion axis, and the vertical axis. When the telescope is pointed at a target object, the angle of each of these axes can be measured with great precision, typically to seconds arm.
Size of a theodolite is specified by
a) the length of telescope
b) the diameter of vertical circle
c) the diameter of lower plate
d) the diameter of upper plate
Ans: C