Surveying Quiz on “Theory of Direct Levelling(Spirit Levelling)”.
1. A level provides a vertical line of sight, a line tangential to a Level surface at the point where the instrument stands.
a) True
b) False
Answer: b
Clarification: A level provides a horizontal line of sight. A line tangential to a Level surface at the point where the instrument stands.
2. The theory of direct levelling neglects _____
a) curvature of the earth
b) refraction
c) both curvature of earth and refraction
d) radius of the earth
Answer: c
Clarification: Neglecting the curvature of earth and refraction, therefore, the theory of direct levelling is very simple. Radius of the earth doesn’t have any criteria.
3. Which of the following methods of spirit levelling is, levelling the object of which is solely to determine the difference in elevation of two points regardless of the horizontal position of the points with respect to each other?
a) Profile levelling
b) Cross levelling
c) Differential levelling
d) Reciprocal levelling
Answer: c
Clarification: Differential levelling is the method of direct levelling the object of which is solely to determine the difference in elevation of two points regardless of the horizontal position of the points with respect to each other. This type of levelling is also called fly levelling.
4. Fly levelling is another name of _____
a) Profile levelling
b) Cross levelling
c) Differential levelling
d) Reciprocal levelling
Answer: c
Clarification: Differential levelling is the method of direct levelling the object of which is solely to determine the difference in elevation of two points regardless of the horizontal position of the points with respect to each other. This type of levelling is also called fly levelling.
5. Which of the following methods of spirit levelling is, levelling the object of which is solely to determine the elevations of points at measured intervals along a given line?
a) Profile levelling
b) Cross levelling
c) Differential levelling
d) Reciprocal levelling
Answer: a
Clarification: Profile levelling is a direct levelling the object of which is solely to determine the elevations of points at measured intervals along a given line. It is done in order to obtain a profile of the surface along that line.
6. Cross sectioning is the process of taking levels on each side of a main line tangential to that line.
a) True
b) False
Answer: b
Clarification: Cross sectioning is the process of taking levels on each side of the main line at right angles to that line. It is also called cross levelling.
7. Which of the following methods of spirit levelling is, levelling in which the difference in elevation between two points is accurately determined by two sets of reciprocal observations?
a) Profile levelling
b) Cross levelling
c) Differential levelling
d) Reciprocal levelling
Answer: d
Clarification: Reciprocal levelling is the method of levelling in which the difference in elevation between two points is accurately determined by two sets of reciprocal observations. It is done only when it is not possible to set up the level between the two lines.
8. Which of the following methods of spirit levelling is, levelling in which the degree of precision required is too great to be attained by ordinary methods?
a) Profile levelling
b) Precise levelling
c) Differential levelling
d) Reciprocal levelling
Answer: b
Clarification: Precise levelling is the levelling in which the degree of precision required is too great to be attained by ordinary methods. Therefore, special equipment or special precaution or both are necessary to eliminate all sources of errors as far as possible.
9. What is the height of instrument, if elevation of benchmark is 200.852 m, back sight is 2.324 m, fore sight is 1.836 m?
a) 213.176
b) 203.176
c) 211.340
d) 201.340
Answer: b
Clarification: Height of instrument is obtained by adding the elevation of benchmark and back sight. Here, 201.852 + 2.324 = 203.176 m.
10. What is the elevation of a point, if the elevation of a benchmark is 200.852 m, back sight is 2.324 m, foresight is 1.836 m?
a) 213.176
b) 203.176
c) 211.340
d) 201.340
Answer: d
Clarification: Elevation of a point is obtained by subtracting the elevation of benchmark and foresight. Here, 201.852 – 1.836 = 201.340 m.
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