The spire test is conducted to adjust the horizontal axis of a theodolite. This ensures that the horizontal axis is truly perpendicular to the vertical axis, which is essential for accurate angular measurements in surveying
In levelling between two points A and B on the opposite banks of a river, the readings are taken by setting the instrument both at A and B, as shown in the table. If the RL of A is 150.000 m, the RL of B (in m) is ....... (rounded off to 3 decimal places).