The ratio of the angles subtended at the eye, by the virtual image and the object, is known as telescope's

The curve composed of two arcs of different radii having their centres on the opposite side of the curve, is known

Probable systematic error in precise levelling as recommended by International Geodetic Association should not exceed
(where k is in kilometers.)

A dumpy level is set up with its eye-piece vertically over a peg A. The height from the top of peg A to the centre of the eye-piece is 1.540 m and the reading on peg B is 0.705 m. The level is then setup over B. The height of the eye-piece above peg B is 1.490 m and a reading on A is 2.195 m. The difference in level between A and B is

Plotting of inaccessible points on a plane table, is done by