# Civil Engineering - Surveying

Exercise : Surveying - Section 7
11.
A lens or combination of lenses in which the following defect is completely eliminated is called aplanatic
spherical aberration
chromatic aberration
coma
astigmatism.
Explanation:
No answer description is available. Let's discuss.

12.
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
0.02 cm
0.15 cm
02 cm
0.1 cm
Explanation:
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13.
In precision theodolite traverse if included angles are read twice and the mean reading accepted using both verniers having a least count of 30". Assuming the instrument to be in perfect adjustment, linear measurements correct to 6 mm per 30 metre tape duly corrected for temperature, slope and sag, the angular error of closure not to exceed (where n is the number of traverse legs)
50" n
30" n
60" n.
Explanation:
No answer description is available. Let's discuss.

14.
Straight, parallel and widely spaced contours represent
a steep surface
a flat surface
an inclined plane surface
curved surface.