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# Survey (281-300)

Updated: Apr 25, 2020

281. Following statements pertain to the position of Sun when it lies over the First

Point of Aries:

1. Its right ascension is zero.

2. Its declination is zero.

282. In Fig. 2.5, the latitude of the place of observation will be equal to declination of the star plus its co-altitude when the position of the star on the meridian is

between equator and zenith

283.A star is observed at its western elongation. If the latitude of place of

observation is θ, the declination of star is δ, altitude of star at elongation is α, then

the hour angle of star is given by

cos H = tanθ . cot δ

284. In photogrammetric surveying, the image of the top of the hill is 90 mm from the principal point of the photograph. If the elevation of the top of the hill is 500 m and the flying height is 5000 m above datum, then the relief displacement is 9 mm

285.A. Perspective centre-The point where the rays from the objects converge B. Plumb Point-The point where the vertical through the optical centre meets the photograph C. Principal point- The point where the perpendicular from the optical centre of the lens meets the photograph D. Isocentre - The point where the bisector of the angle between vertical & perpendicular from optical centre meet the photograph

286. It is required to determine by periodical soundings, the rate at which silting or scouring is taking place in a harbour. Which one of the following methods is

best suited for locating the positions of the soundings ?

Intersecting ranges

287. The representative fraction 1/2500 means that the scale is 1 cm equal t 25 m

288. Which of the following are the fundamental lines of a theodolite ?

1. The vertical and horizontal axes

2. The line of collimation and axes of the plate levels

3. The bubble line of the attitude level

Select the correct answer using the codes given below.

289. Which of the following characteristic features may be used while plotting a

contour plan ?

1. Two contour lines having the same elevation cannot unite and continue as

one line..

3. Contour lines cross a valley line at right angle

290.1. Three-point problem is solved by Bessel's method.

2. In two-point problem, auxiliary station is required.

291. Which one of the following specifications for length of base line refers to "Third Order Triangulation system? 0.5 to 3 km

292. If R is the radius of the main curve, θ the angle of deflection, S the shift and L the length of the transition curve, then the total tangent length of the curve is given by (R+S)tan θ/2 + L/2

293. The difference between the sum of the angles of a plane triangle and the sum of the angles of a spherical triangle is one second when the triangle on the earth surface has an area of about 195 sq.km

294. A plan of an area drawn with the original scale of 1 cm = 10 m, has shrunk such that a line, originally 15 cm long on the plan, measures now 14.5 cm. The shrunk scale is given by 1 cm equal to 10.34 m

295. The two-peg test in the adjustment of a dumpy level employs the principle that -reciprocal levelling eliminates errors of non-parallel instrument and collimation axes.

296. 1. Plane Table survey-For preparation of small-scale map 2. Triangulation survey-To fix the centre line of piers, and abutments of long bridges 3. Trilateration survey-The three sides of the triangles are measured

297. The length of a transition curve for a circular curve of radius 300 m and for a

design speed of 15 m/s, when the rate of change of centrifugal acceleration is 0.3

m/s³, is 37.5 m

298. If the line of sight between two stations A and B, on sea, and 80 km apart, makes tangent at point A, then the minimum elevation of the signal required at

B(considering the coefficient of refraction 'm' = 0.08 and the mean radius of earth as 6400 km) will be 420 m

299. In a closed theodolite traverse, the sum of the latitudes is + 5.080 m and the sum of the departures is -51.406 m, the sum of the traverse legs is 20.525 km. The

accuracy of traverse is nearly equal to 1 :400

300. A sewer is laid from a manhole A to a manhole B, 250 m apart along a

downward gradient of 1 in 125. If the reduced level of the invert at A is 205.75

m and the height of the boning rod is 3 m then, reduced level of the sight rail at B, is 206.75 m