SSC JE Exam - theodolite traversing adjustment levelling contouring curvature refraction corrections Online Test (MCQ Quiz)

1. What is the primary purpose of a theodolite in surveying?

A) To measure vertical distances B) To measure horizontal and vertical angles C) To determine the area of irregular shapes D) To establish elevation points

2. In theodolite traversing, what is the process of orienting the instrument to a known direction called?

A) Plunging B) Setting up C) Centering D) Reconnaissance

3. What is the term for the process of determining the horizontal and vertical positions of points relative to each other using a theodolite?

A) Levelling B) Contouring C) Traversing D) Triangulation

4. Which of the following is a fundamental component of a theodolite used for measuring horizontal angles?

A) Vertical circle B) Telescope C) Vernier scale or digital display D) Leveling screws

5. What is the 'line of collimation' in a theodolite?

A) The line connecting the eyepiece to the objective lens B) The line connecting the objective lens to the point being sighted C) The horizontal line passing through the optical center of the telescope D) The line representing the direction of gravity

6. When measuring a horizontal angle with a theodolite, what does 'transiting' (or plunging) the telescope mean?

A) Rotating the telescope 180 degrees in the horizontal plane B) Rotating the telescope 180 degrees in the vertical plane C) Moving the telescope from left to right D) Locking the horizontal clamp

7. What is the purpose of 'adjustment' in the context of theodolite traversing?

A) To increase the magnification of the telescope B) To correct for instrumental and observational errors C) To measure the curvature of the Earth D) To determine the magnetic declination

8. Which adjustment in a theodolite ensures that the horizontal axis is perpendicular to the vertical axis?

A) Adjustment of the plate levels B) Adjustment of the telescope's objective C) Adjustment of the vertical circle index D) Adjustment of the line of collimation

9. The process of determining the relative elevations of points on the ground is known as:

A) Traversing B) Contouring C) Levelling D) Setting out

10. In levelling, what is a 'level surface'?

A) A flat, horizontal surface B) A surface perpendicular to the direction of gravity at all points C) A surface parallel to the mean sea level D) A surface defined by a constant elevation

11. What is a 'bench mark' (BM) in surveying?

A) A temporary point used for sighting B) A point of known elevation used as a reference C) A point used to establish horizontal control D) A point marking the end of a traverse leg

12. What is a 'backsight' (BS) reading in differential levelling?

A) A reading taken on a point in the forward direction of the survey B) A reading taken on a point of known elevation C) A reading taken on a graduated staff held vertically on a point of known or assumed elevation, towards the instrument D) A reading taken on a point where the instrument is to be moved next

13. What is a 'foresight' (FS) reading in differential levelling?

A) A reading taken on a point in the backward direction of the survey B) A reading taken on a point of unknown elevation, in the forward direction from the instrument C) A reading taken on a bench mark D) A reading taken on the starting point of a level line

14. The difference between the average foresight and average backsight readings in a levelling circuit should ideally be equal to:

A) The total horizontal distance covered B) The difference in elevation between the start and end points C) Zero, if the circuit starts and ends at the same point D) The sum of all intermediate sight readings

15. What is 'rise and fall' levelling?

A) A method to determine horizontal distances B) A method where both the difference in elevation (rise or fall) between consecutive points and the elevation of each point are calculated C) A method used for contouring D) A method to measure vertical angles

16. What is a contour line?

A) A line connecting points of equal horizontal distance B) A line connecting points of equal elevation C) A line representing the direction of steepest slope D) A line marking the boundary of a survey area

17. The horizontal distance between two adjacent contour lines indicates:

A) The direction of the slope B) The steepness of the slope C) The length of the contour line D) The elevation difference between the lines

18. Closely spaced contour lines represent:

A) Gentle slopes B) Uniform slopes C) Steep slopes D) Flat terrain

19. Widely spaced contour lines represent:

A) Steep slopes B) Uniform slopes C) Gentle slopes D) Vertical cliffs

20. A contour line that forms a closed loop with higher elevations inside represents a:

A) Depression B) Hill or peak C) Valley D) Saddle

21. A contour line that forms a closed loop with lower elevations inside represents a:

A) Hill or peak B) Depression or pit C) Ridge D) Plateau

22. Contour lines that V-shape upstream in a valley indicate:

A) A ridge B) A peak C) A stream or valley D) A saddle

23. Contour lines that U-shape downstream in a ridge indicate:

A) A valley B) A depression C) A saddle D) A ridge

24. What is the 'contour interval'?

A) The horizontal distance between two contour lines B) The vertical distance between two adjacent contour lines C) The frequency with which contour lines are plotted D) The difference in elevation between the highest and lowest points

25. The effect of the Earth's curvature on a level line of sight is to make it appear:

A) Higher than it actually is B) Lower than it actually is C) The same as it actually is D) Erratic

26. The effect of atmospheric refraction on a level line of sight is to make it appear:

A) Higher than it actually is B) Lower than it actually is C) The same as it actually is D) Bent upwards

27. In levelling, the combined effect of Earth's curvature and refraction makes the observed level line of sight appear:

A) Higher than the true horizontal line B) Lower than the true horizontal line C) Coincident with the true horizontal line D) Divergent from the true horizontal line

28. The combined correction for curvature and refraction for a distance 'd' (in km) is approximately:

A) 0.0112 d^2 B) 0.0785 d^2 C) 0.112 d^2 D) 0.785 d^2

29. Which correction needs to be applied to reduce the observed staff reading to the true horizontal distance due to Earth's curvature and refraction?

A) Additive correction B) Subtractive correction C) No correction is needed D) Reciprocal correction

30. For reciprocal levelling, what is the primary advantage?

A) It eliminates the need for a level B) It cancels out the effects of curvature and refraction C) It is faster than differential levelling D) It is more accurate for short distances

31. In theodolite traversing, what is meant by 'closing the horizon'?

A) Measuring the angle to the true north B) Ensuring the sum of interior angles of a closed traverse equals (n-2) * 180 degrees C) Plunging the telescope after taking a reading D) Setting up the instrument perfectly level

32. What is the 'face left' (FL) and 'face right' (FR) observation in theodolite use?

A) Observing the target with the telescope in its normal position and then inverted B) Observing the target from the left and right sides of the instrument C) Measuring horizontal angles to the left and right D) Checking the level bubble from left and right

33. What is the purpose of measuring angles in both Face Left and Face Right positions in theodolite traversing?

A) To increase accuracy and eliminate errors due to imperfect adjustment B) To measure vertical angles simultaneously C) To speed up the process of traversing D) To determine the elevation of points

34. What is 'station adjustment' in a closed traverse?

A) Adjusting the length of traverse legs B) Adjusting the angles at each station to satisfy the geometric conditions of the traverse C) Adjusting the elevations of stations D) Adjusting the instrument's levels

35. The process of determining the latitude and departure of each course in a traverse is called:

A) Levelling B) Balancing the traverse C) Computation of coordinates D) Contouring

36. In levelling, what is the 'height of instrument' (HI)?

A) The elevation of the point on which the staff is held B) The elevation of the ground surface C) The elevation of the horizontal line of sight of the instrument D) The vertical distance from the ground to the telescope

37. Which instrument is typically used for precise levelling?

A) Theodolite B) Plane table C) Dumpy level or Automatic level D) Total station

38. What is a 'profile levelling'?

A) Levelling to determine the elevations of points along a line, typically for roads or canals B) Levelling to create contour lines C) Levelling to establish bench marks D) Levelling to find the difference in elevation between two distant points

39. What is a 'cross-section' in the context of levelling for infrastructure projects?

A) A section taken along the length of the project B) A section taken perpendicular to the line of the project to show ground variations C) A section showing the contour lines D) A section showing the overall elevation profile

40. In contouring, what is the 'index contour'?

A) A contour line that is thicker and is usually labelled with its elevation B) A contour line representing the highest elevation C) A contour line representing the lowest elevation D) A contour line that is very closely spaced

41. What is the primary method for determining contour lines from field data?

A) Tachometry B) Grid method C) Triangulation D) Resection

42. The correction for curvature alone for a distance 'd' (in km) is approximately:

A) 0.0112 d^2 B) 0.0785 d^2 C) 0.112 d^2 D) 0.785 d^2

43. The correction for refraction alone for a distance 'd' (in km) is approximately:

A) 0.0112 d^2 B) 0.0785 d^2 C) 0.112 d^2 D) 0.785 d^2

44. When the line of sight is tangential to the Earth's surface at the instrument station, the correction for curvature is:

A) Added B) Subtracted C) Zero D) Depends on the distance

45. In theodolite traversing, what is 'intervisibility'?

A) The ability to see the instrument from the target B) The ability to see the target clearly from the instrument station C) The ability to measure both horizontal and vertical angles D) The ability to establish a level line of sight

46. What is the 'meridian' in surveying?

A) The line connecting two points at the same elevation B) A fixed direction line, usually true north or south, used as a reference C) The line of sight of the telescope D) The path of the sun across the sky

47. The process of determining the magnetic declination at a survey site is important for:

A) Levelling B) Contouring C) Establishing true bearings from magnetic bearings D) Calculating area

theodolite traversing adjustment levelling contouring curvature refraction corrections - Online Test

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