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Question 1
ప్రశ్న 1
For setting the invert of a proposed sewer, the surveyor must establish how high one site point is relative to another. Which is the primary purpose of ordinary geometric levelling?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Geometric levelling is used to establish vertical relationships between points. A level provides a nearly horizontal line of sight and a staff provides readings at the points. Their readings allow differences in elevation to be determined. Elevations can then be referred to a specified vertical datum. This information is essential for setting sewer inverts and waterworks levels. Bearings and enclosed areas are not the primary results of ordinary levelling.
వివరణ:
Question 2
ప్రశ్న 2
Which statement best describes a LEVEL SURFACE in surveying?
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Explanation:
A level surface is an equipotential surface of the Earth's gravity field. The local direction of gravity is perpendicular to it. Such a surface generally curves rather than being an infinite plane. A horizontal plane is tangent to a level surface at a particular point. The distinction becomes important over extended distances. Ordinary short-sight levelling often uses a local horizontal line as an adequate approximation.
వివరణ:
Question 3
ప్రశ్న 3
At a particular point P, how is the HORIZONTAL PLANE geometrically related to the level surface passing through P?
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Explanation:
The level surface passing through P is generally curved. A horizontal plane at P is tangent to that surface. The local vertical direction is perpendicular to the tangent horizontal plane. A plane containing the vertical cannot be the horizontal plane. The tangent description applies at the stated point, not across unlimited distances. Surveyors use this local geometry when defining a horizontal line of sight.
వివరణ:
Question 4
ప్రశ్న 4
A plumb bob is suspended freely at a levelling station. Which statement correctly describes the local VERTICAL direction used in levelling?
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Explanation:
A freely suspended plumb bob indicates the local gravity direction. This direction defines the local vertical in physical levelling. The vertical is normal to a level or equipotential surface at the station. Verticals at widely separated points need not be parallel. A tangent to a level surface defines a horizontal direction instead. A construction baseline has no necessary relationship to the gravity direction.
వివరణ:
Question 5
ప్రశ్న 5
The reduced level (RL) of an inspection-chamber cover is recorded as +96.425 m relative to a specified site datum. Which interpretation is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A reduced level is an elevation expressed relative to a chosen vertical datum. A positive RL denotes a point above the adopted zero reference. The numerical value does not specify the distance to the level instrument. It also does not represent the height of the telescope above the ground. An arbitrary site datum may differ from an official mean-sea-level-based datum. The adopted datum must therefore accompany RL information in engineering records.
వివరణ:
Question 6
ప్రశ్న 6
A project initially assigns an arbitrary benchmark an RL of 0.000 m. The same benchmark is then assigned RL 100.000 m under a revised ARBITRARY datum, with all measured height differences unchanged. What happens to the RL of every connected point?
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Explanation:
The revised datum changes the numerical origin of the elevation system. The reference benchmark receives a constant increase of one hundred metres. Every point connected by the same levelling observations receives the same additive shift. Subtracting any two revised RLs cancels that shift. Hence physical height differences remain unchanged. This is why datum changes must be applied consistently to every related elevation.
వివరణ:
Question 7
ప్రశ్న 7
A survey team needs reliable vertical control for several future phases of a water-treatment plant. Which feature most directly qualifies a point as a BENCHMARK?
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Explanation:
A benchmark provides a reference elevation for subsequent levelling work. Its position should be identifiable and sufficiently stable for its intended use. Its reduced level must be known relative to a stated datum. A tripod position is not automatically a benchmark. A known horizontal direction alone supplies no vertical reference. Establishing dependable benchmarks helps maintain consistent elevations across construction stages.
వివరణ:
Question 8
ప్రశ్న 8
Levelling of a rising main will stop overnight, and the crew must resume from a recoverable height reference the following day. What is the best practice?
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Explanation:
A temporary benchmark is used to preserve elevation control during an interruption of work. It should be placed on a stable and identifiable feature. Its reduced level must be transferred from existing vertical control. The location and value should be recorded clearly enough for reoccupation. A loose point or disturbed tripod foot may change elevation. The temporary benchmark allows the next levelling setup to begin from a known height.
వివరణ:
Question 9
ప్రశ్న 9
A design drawing specifies elevations relative to an established mean-sea-level-based vertical datum, but a site levelling exercise uses a locally assumed RL of 100.000 m at one point. What is required before the site RLs can be used as elevations on the design datum?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
An arbitrary datum is valid for obtaining relative elevations within a site. It is not automatically identical to the datum used on a design drawing. Connecting the site reference to a benchmark on the specified datum establishes the required offset. That offset can then be applied consistently to all related RLs. The instrument height at a single setup does not establish a datum transformation. A magnetic bearing supplies direction rather than the required vertical relationship.
వివరణ:
Question 10
ప్రశ్న 10
Which line is referred to as the LINE OF COLLIMATION of a properly adjusted optical level?
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Explanation:
The line of collimation is defined by the optical alignment of the telescope. It passes through the intersection of the crosshairs and the optical centre of the objective. This line establishes the direction at which the staff is read. In a properly adjusted and levelled instrument it should be horizontal. The tripod axis and staff axis are different geometrical lines. Correct collimation is essential for comparing staff readings accurately.
వివరణ:
Question 11
ప్రశ్న 11
A level telescope has been correctly adjusted and brought into its operating level condition. Which statement best describes its line of sight for a conventional SHORT-SIGHT geometric levelling observation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A level telescope is adjusted to provide a local horizontal line of sight. For the usual short sights, its elevation is treated as constant during a fixed setup. Staff readings measure vertical separations from that sight line to the points observed. The sight line does not follow the curvature of a level surface exactly over long distances. It is not directed vertically or along the ground slope. This establishes the basis of the height-of-instrument method.
వివరణ:
Question 12
ప్రశ్న 12
In a levelling field book, the HEIGHT OF INSTRUMENT (HI), also called the height of collimation, refers to which quantity?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Height of instrument in levelling is an elevation, not a mechanical dimension of the tripod. It represents the reduced level of the horizontal line of collimation. It is obtained by adding a backsight reading to the known RL of the observed reference point. Unknown RLs in the same setup can then be found by subtracting staff readings. The numerical HI may be much greater than the telescope's height above nearby ground. The adopted datum remains the reference for this elevation.
వివరణ:
Question 13
ప్రశ్న 13
What is the principal function of the internal COMPENSATOR of an automatic level after the instrument has been approximately levelled within its specified working range?
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Explanation:
An automatic level contains a compensating optical or mechanical system. After approximate levelling, this system corrects small residual tilts of the instrument. Its purpose is to produce an effectively horizontal line of sight within its operating range. The compensator does not determine azimuth or magnetic declination. It also does not eliminate the need for a vertical staff and suitable observations. The instrument still must be set up stably and checked before readings are accepted.
వివరణ:
Question 14
ప్రశ్న 14
For a correctly adjusted conventional dumpy level, why are the foot screws used to centre the spirit-level bubble before staff readings are taken?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The foot screws alter the instrument's tilt on its support. The spirit-level bubble indicates whether the relevant level condition has been achieved. For a correctly adjusted instrument, centring the bubble brings the sight line into its required horizontal condition. This enables valid comparison of staff readings from the setup. The screws do not control magnification or establish a vertical datum. A known elevation reference is still needed to assign numerical RLs.
వివరణ:
Question 15
ప్రశ్న 15
An optical level is properly levelled, but its crosshairs seem to move relative to a stationary staff graduation when the observer moves the eye slightly. What should be done before recording the reading?
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Explanation:
Apparent motion between the crosshairs and staff image is characteristic of parallax. It occurs when the image and reticle are not in the appropriate focal relationship. The eyepiece is adjusted to make the crosshairs sharp. The objective focusing control then brings the staff image into focus. The observer should verify that slight eye movement does not produce relative image motion. Removing parallax reduces reading uncertainty before booking the observation.
వివరణ:
Question 16
ప్రశ్న 16
A levelling staff is held noticeably out of plumb on a firm point while a horizontal line of sight intersects its graduation. Compared with a truly vertical staff on the SAME point, what is the usual effect on the positive staff reading?
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Explanation:
The staff is intended to be vertical so its graduations represent vertical distances above its foot. When the staff is tilted, a given horizontal height normally intersects it at a larger graduation than when it is upright. Such an excessive reading can bias a computed RL downward. A staff bubble can be used to keep the rod plumb. With suitable conditions, gentle rocking allows the observer to identify the minimum reading. Staff verticality is therefore a basic field requirement for reliable levelling.
వివరణ:
Question 17
ప్రశ్న 17
A level is set up at I1, and its FIRST staff reading of 1.625 m is taken on benchmark A with known RL. What is this sight called, and what is its direct computational role?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The first staff observation after setting up a level is called the backsight in the ordinary levelling sequence. It is taken on a point whose reduced level is known, commonly a benchmark or change point. The reading provides the vertical distance from that point to the line of sight. Adding it to the known RL gives the height of instrument. Later readings from the same setup can be reduced using this HI. The label backsight identifies its role, not the compass direction of the line of sight.
వివరణ:
Question 18
ప్రశ్న 18
From one fixed setup, the staff is read successively at known BM (1.250 m), drain invert point P (2.020 m), change point CP (1.885 m), after which the LEVEL IS MOVED. Which classification of the three readings is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The first reading from a levelling setup on a known point is the backsight. In this sequence the benchmark observation serves that role. A reading to point P made between the first and last observations is an intermediate sight. The last reading before moving the instrument is the foresight. The observation at CP is therefore entered in the foresight column. After relocation, a new backsight on the same CP transfers the reduced level to the next setup.
వివరణ:
Question 19
ప్రశ్న 19
A crew uses a change point while shifting a level between two setups. Which combination of observations and field precautions is correct?
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Explanation:
A change point transfers elevation from one instrument setup to the next. The first setup ends with a foresight to that point. Its RL is computed from the first setup's height of instrument. After moving the level, a backsight is taken to the same physical point. The point should be stable and well identified so its elevation does not change between readings. These two observations allow a new height of collimation to be established consistently.
వివరణ:
Question 20
ప్రశ్న 20
A benchmark has RL 102.475 m. From a newly levelled setup, the BACKSIGHT on it is 1.325 m. What is the height of instrument for that setup?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Height of instrument is the elevation of the line of collimation. It is computed by adding the backsight to the RL of the known point. Here the RL is 102.475 m and the backsight is 1.325 m. Their sum is 103.800 m. The benchmark has not changed elevation because a staff reading was taken. This HI can be used to compute other RLs observed without moving the instrument.
వివరణ:
Question 21
ప్రశ్న 21
The height of collimation for a fixed setup is 98.560 m. An intermediate sight of 1.745 m is observed on a valve-chamber floor point. What is the reduced level of that point?
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Explanation:
A vertical staff reading represents the distance from the observed point up to the horizontal line of sight. The line of sight is at RL 98.560 m in this setup. Therefore the staff reading must be subtracted to obtain the point RL. Subtracting 1.745 m gives 96.815 m. The result is below the height of collimation, as expected for a positive upright-staff reading. Whether the observation is an intermediate sight or foresight does not change this subtraction rule.
వివరణ:
Question 22
ప్రశ్న 22
From one UNCHANGED level setup with an upright staff, the backsight on point A is 1.200 m and a later intermediate sight on point B is 2.475 m. How does the RL of B compare with the RL of A?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Both readings are referred to the same horizontal line of sight. A larger positive staff reading corresponds to a point at a lower elevation. The difference in readings is 2.475 - 1.200 = 1.275 m. Hence B is 1.275 m below A. The absolute RL of A is not required to compute this difference. Moving the instrument between the readings would invalidate the simple comparison unless the setup elevations were accounted for.
వివరణ:
Question 23
ప్రశ్న 23
A differential levelling run starts from BM with RL 100.000 m. In the first setup BS on BM = 1.350 m and FS on CP = 2.080 m. After shifting the level, BS on the SAME CP = 0.950 m and FS on endpoint E = 1.465 m. Assuming upright staffs and no errors, what is RL of E?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The first setup has HI1 = 100.000 + 1.350 = 101.350 m. The change point RL is 101.350 - 2.080 = 99.270 m. The second setup has HI2 = 99.270 + 0.950 = 100.220 m. The endpoint RL is then 100.220 - 1.465 = 98.755 m. The change point is the same physical reference across the shift. The backsight on it establishes the new line-of-sight elevation, rather than changing the point RL.
వివరణ:
Question 24
ప్రశ్న 24
Two points P and Q are observed from the same correctly levelled instrument setup with positive upright-staff readings P = 1.800 m and Q = 1.050 m. Which statement is correct?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The line of collimation has the same elevation for both observations. A smaller staff reading indicates a point closer vertically to that line from below. The reading at Q is 0.750 m smaller than the reading at P. Thus Q lies 0.750 m higher than P. This comparison requires no knowledge of the absolute height of collimation. The conclusion assumes both readings use upright staffs and the same undisturbed setup.
వివరణ:
Question 25
ప్రశ్న 25
A levelling run starts at a benchmark of RL 75.250 m. Across two setups the BS readings are 1.420 m and 0.860 m, and the FS readings are 2.110 m and 1.170 m, respectively. The intervening FS and next BS are on the same change point. What is the final RL from the standard levelling arithmetic relation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The change in reduced level across a correctly booked levelling run equals the sum of backsights minus the sum of foresights. The backsights sum to 1.420 + 0.860 = 2.280 m. The foresights sum to 2.110 + 1.170 = 3.280 m. The net height change is therefore -1.000 m. Adding that change to the initial RL of 75.250 m gives 74.250 m. Intermediate sights do not enter this endpoint arithmetic relation.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: C. To establish elevations or differences in elevation relative to a chosen vertical datum. సమాధానం: C.
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Question 2 ప్రశ్న 2Answer: A. A curved equipotential surface to which the local gravity direction is normal at every point. సమాధానం: A.
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Question 3 ప్రశ్న 3Answer: B. It is the plane tangent to that level surface at P and perpendicular to the local vertical. సమాధానం: B.
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Question 4 ప్రశ్న 4Answer: D. It follows the direction of gravity and is normal to the local level surface. సమాధానం: D.
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Question 5 ప్రశ్న 5Answer: C. The cover has an elevation 96.425 m above the adopted zero-datum level. సమాధానం: C.
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Question 6 ప్రశ్న 6Answer: B. Every RL increases by 100.000 m, while differences in RL between points remain unchanged. సమాధానం: B.
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Question 7 ప్రశ్న 7Answer: A. It is a recoverable marked point with an established reduced level referred to the specified datum. సమాధానం: A.
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Question 8 ప్రశ్న 8Answer: D. Establish and document a stable temporary benchmark with a transferred RL before ending the day. సమాధానం: D.
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Question 9 ప్రశ్న 9Answer: C. Establish the vertical offset by tying the local reference to control with known elevations on the design datum. సమాధానం: C.
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Question 10 ప్రశ్న 10Answer: B. The sight line defined by the intersection of the crosshairs and the optical centre of the objective. సమాధానం: B.
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Question 11 ప్రశ్న 11Answer: A. It represents a local horizontal line of sight whose elevation is treated as constant for the instrument setup. సమాధానం: A.
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Question 12 ప్రశ్న 12Answer: D. The reduced level of the instrument's horizontal line of collimation relative to the adopted datum. సమాధానం: D.
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Question 13 ప్రశ్న 13Answer: C. To maintain an effectively horizontal line of sight despite small residual instrument tilts. సమాధానం: C.
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Question 14 ప్రశ్న 14Answer: B. To bring the instrument into the level condition required for its collimation line to be horizontal. సమాధానం: B.
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Question 15 ప్రశ్న 15Answer: D. Remove parallax by correctly focusing the eyepiece on the crosshairs and the objective on the staff image. సమాధానం: D.
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Question 16 ప్రశ్న 16Answer: A. The inclined staff generally gives an excessively large reading, so it should be held vertical or carefully rocked to obtain the minimum. సమాధానం: A.
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Question 17 ప్రశ్న 17Answer: C. Backsight, which is added to the known RL of A to establish the HI for this setup. సమాధానం: C.
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Question 18 ప్రశ్న 18Answer: B. BM = BS; P = IS; CP = FS. సమాధానం: B.
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Question 19 ప్రశ్న 19Answer: D. Take a foresight to a stable identifiable point before shifting and a backsight to that SAME point afterward. సమాధానం: D.
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Question 20 ప్రశ్న 20Answer: A. 103.800 m. సమాధానం: A.
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Question 21 ప్రశ్న 21Answer: C. 96.815 m. సమాధానం: C.
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Question 22 ప్రశ్న 22Answer: B. B is 1.275 m lower than A. సమాధానం: B.
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Question 23 ప్రశ్న 23Answer: D. 98.755 m. సమాధానం: D.
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Question 24 ప్రశ్న 24Answer: A. Q is 0.750 m higher than P. సమాధానం: A.
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Question 25 ప్రశ్న 25Answer: C. 74.250 m. సమాధానం: C.