246. A dumpy level was set up at the mid-point between two pegs A and B, 50 m apart and the staff readings at A and B were 1.22 and 1.06. With the level set up a A, the readings at A and B were 1.55 and 1.37. The collimation error per 100 m length of sight is

A. 0.02 m inclined upwards

B. 0.04 m inclined downwards

C. 0.04 m inclined upward

D. none of these.

247. The bearings of the lines AB and BC are 146? 30' and 68? 30'. The included angle ABC is

A. 102?

B. 78?

C. 45?

D. none of these.

248. While setting a plane table at a station it was found that the error in centering was 30 cm away from the ray of length 40 m drawn from the station. If the scale of the plan is 1. cm = 2 cm, the displacement of the end of the ray in plan from the true position will be

A. 0.02 cm

B. 0.15 cm

C. 02 cm

D. 0.1 cm.

249. The staff reading at a distance of 80 m from a level with the bubble at its centre is 1.31 m. When the bubble is moved by 5 divisions out of the centre, the reading is 1.39 m. The angular value of the one division of the bubble, is

A. 28.8 secs

B. 41.25 secs

C. 14.52 secs

D.25.05

250. Staff readings on pegs x and y from X station are 1.755 m and 2.850 m, and from station Y on staff head at Y and X are 0.655 m and 1.560 m. If,reduced level of X is 105.5 m, the reduced level of Y is

A. 104.0 m

B. 104.5 m

C. 105.0 m

D. 105.5 m.

251. Probable accidental error in precise levelling as recommended by International Geodetic Association, should not exceed where k is in kilometers.

A. ? 0.1 qiz mm

B.C ? 1 -Vre mm

C.B ? 0.5 AT? Mm

D. ? 2 v-k- mm

252. Probable systematic error in precise levelling as recommended by International Geodetic Association should not exceed

A. ? 0.1 -4-k- mm

B. ? 0.2 Alrz mm

C. ? 0.1 Airz

D.0.2

Page **36** of **60**