The representative fraction of the scale1 cm = 5 km is

A portion of embankment having a uniform up gradient of 1 in 500 is circular with a radius of 1000 m of the centre line. It subtends 180° at the centre. If the height of the embankment is 1 m at the lower end and side slope is 2 : 1, the earth work involved is

The constant vertical distance between two consecutive contour is

The length of revenue chain

The instrument belongs to a class of reflecting instrument is