Survey (241-260)

Updated: Apr 24, 2020

241. If the gradient of a ground is -3%, that of another ground intersecting with the

former is 5%, and the horizontal length of the vertical curve to be drawn is 600 m,

then the vertical offset 'e' from the vertex of the vertical curve to the mid-point of

the curve will be 6 m

242. Consider the following statements regarding base-line measurements:

1. Error : due to application of non standardized pull on the tape can be either cumulative or compensating type.

2. Intermediate obstructions in the measurement on base-lines can be

cleared by erecting towers

243.Apparent displacement of signal i azimuth-Due to dislevelment of trunnion axis Error due to phase of the signal Sun illuminating only a portion of the signal Error due to eccentric signal-Location of signal displaced from the actual site due to difficulties in erection Error due to refraction-Light rays travelling from a rarer to a denser medium

244. A star is observed at its upper culmination when it is north of zenith. The latitude of the place of observation is 30°N and declination of the star is 50°N. The zenith distance of the star is 20°

245. The local sidereal time (LST) is always behind LMT by about 2 hours per

month

246. Consider the following statements regarding the longitude of a place : wireless time signals,transportation of chronometers

247. In an aerial photo, the image of the top of a tower is found to be 10 cm from the center of the photograph. If the height of the tower is 100 m and the flying height of the aircraft is 1000 m above the average terrain height, then the height

displacement of the image from the true position will be 10 mm

248.Reciprocal levelling-Eliminates error due to inclined line of collimation also Balancing Fore Sight and BackSight Distances-Eliminates the collimation error Inverted -Staff Reading-Points above the line of collimation Tilting level-The vertical axis is not perpendicular to the line of collimation


249.The following equipments can be used to lay out horizontal angles in field :

1. Microptic theodolite

2. Vernier theodolite

3. Prismatic compass

4. Chain and metallic


250.If the downhill end of a 20 m tape is held 80 cm too low, then its horizontal length will be 19.984 m

251. When a theodolite is in proper adjustment" which of the following conditions between fundamental lines are satisfied?

1. Axis of the plate level is perpendicular to the vertical axis.

2. The line of collimation is at right angles to the vertical axis.

3. The axis of the altitude level is parallel to the line of collimation when it is horizontal and the vertical circle reads zero

252. The following bearings were taken in running a, closed compass traverse

ABCDA


One would suspect local attraction at stations

C and D

253. ABCD is a regular parallelogram plot of land, whose angle BAD is 60°. If the

bearing of the line AB is 30°, then the bearing of the line CD is

210°

254. In a closed traverse, the following computations were made



Consider the following conclusions drawn from the above computations

Reduced bearing of DA = S 45 °W

W.C.B. of DA = 225°

255. In theodolite traversing, for the calculation of independent rectangular coordinates from the field observations, some of the computations are indicated below

1. Computation of reduced bearing of each traverse leg

2. Calculation of consecutive coordinates

3. Calculation of the closing error

4. Balancing of consecutive coordinates


256.The correct sequence of the "Lehmann's procedure" for solving the "three point problem" is

4. The plane table is levelled over the station point.

5. Three resection lines are drawn from three well-defined station points.

3. 'Triangle of error' is obtained.

1. Using Lehmann's rule, an improved position of station point is obtained.

2. Procedure is repeated till the triangle of error is reduced to a point.

257.A. Equally spaced contour lines - Uniform slope B. Contours are always perpendicular to-Steepest slope C. Contours increase in elevation from inside to outside- A depression

258.Consider the following statements Besides contours, relief on topographic

maps is represented in general, by

1. hachures

2. hypsometric tints

3. hill shading

259.If in a triangle ABC, b = 300 m and angle ABC = 60°, then the radius of the circular curve passing through the points A, B and

C will be 173.2

260.Satellite station S is established during a triangulation survey as shown in Fig.



The angle α is equal to

θ + β₁ + β₂



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