Q31. Calculate the distance between the instrument and the staff, if the staff readings are 1.56 m, 2.05 m and 2.56 m. The multiplying constant is 100 and additive constant is 10.
Difficulty: Medium
A. 61
B. 110
C. 112
D. 215.67
Correct Answer: B. 110Solution:Staff intercept S = 2.56−1.56 = 1.00 m. D = KS+C = (100×1.00)+10 = 110 m.
Q32. Calculate the additive and multiplying constant, if the focal length of the objective glass is 250 mm, stadia intercept is 2 mm and distance of the instrument axis from the centre of the object glass is 190 mm.
Difficulty: Medium
A. 95, 440 mm
B. 125, 440 mm
C. 440, 95 mm
D. 440, 125 mm
Correct Answer: D. 440, 125 mmSolution:K = f/i = 250/2 = 125. C = f+d = 250+190 = 440 mm.
Q33. In which of the following plane, the telescope of the theodolite is turned in order to swing?
Difficulty: Easy
A. Horizontal axis
B. Horizontal plane
C. Inclined plane
D. Vertical plane
Correct Answer: B. Horizontal planeSolution:Swinging rotates the telescope about the vertical axis, sweeping the line of sight through the horizontal plane — opposite to transiting (vertical plane).
Q34. Relative error of the closure is the ratio of:
Difficulty: Easy
A. Closing error to sum of departure
B. Closing error to sum of latitude
C. Closing error to perimeter of traverse
D. Latitude to departure
Correct Answer: C. Closing error to perimeter of traverseSolution:Relative precision normalises the absolute closing error against the total traverse length, expressed as a fraction like 1/5000.
Q35. Which of the following instruments is used for centering the theodolite in windy conditions?
Difficulty: Easy
A. Cross staff
B. Optical plummet
C. Optical square
D. Spirit level
Correct Answer: B. Optical plummetSolution:An optical plummet sights directly down to the ground mark with no hanging cord, avoiding the wind-sway problem of a traditional plumb bob.
Q36. Which of the following is the expression for the additive constant, if f is the focal length of objective?
Difficulty: Easy
A. f − d
B. f/i
C. f + d
D. f × i
Correct Answer: C. f + dSolution:Additive constant C = f+d (focal length plus axis-to-objective distance). f/i is instead the multiplying constant K.
Q37. Which of the following statement is correct for proper adjustment of the theodolite?
Difficulty: Hard
A. Axis of plate level is perpendicular to the horizontal axis
B. Line of collimation is perpendicular to the horizontal axis
C. Line of collimation is parallel to the vertical axis
D. Line of collimation is perpendicular to the vertical axis
Correct Answer: D. Line of collimation is perpendicular to the vertical axisSolution:This is the answer per the source key for this question. Note: the rigorously standard textbook relation (also tested in Q18/Q46) is that the line of collimation is perpendicular to the horizontal axis — see the detailed explanation for the full discussion.
Q38. Which of the following test is used to make the horizontal axis perpendicular to the vertical axis?
Difficulty: Medium
A. Azimuth test
B. Cross hair ring test
C. Spire test
D. Vertical arc test
Correct Answer: C. Spire testSolution:The Spire test sights a high point, transits, swings 180°, and re-sights to detect any horizontal-vertical axis perpendicularity error.
Q39. Which of the following statement is CORRECT when the theodolite is properly adjusted?
Difficulty: Medium
A. Horizontal line passes through the centre of the horizontal circle
B. Tangent to plate bubble must be perpendicular to horizontal axis
C. Tangent to plate bubble must be perpendicular to vertical axis
D. Vertical line passes through the centre of the vertical circle
Correct Answer: C. Tangent to plate bubble must be perpendicular to vertical axisSolution:This restates the plate-level adjustment condition: centring the bubble confirms the vertical axis is vertical only if this perpendicular relationship holds.
Q40. In transit theodolite, the line of the sight can be reversed by revolving the telescope through:
Difficulty: Easy
A. 90 degrees in horizontal plane
B. 90 degrees in vertical plane
C. 180 degrees in horizontal plane
D. 180 degrees in vertical plane
Correct Answer: D. 180 degrees in vertical planeSolution:This 180° vertical-plane reversal about the trunnion axis is exactly what “transiting” means, and is what gives the transit theodolite its name.
Q41. Which one is the CORRECT sequence for the temporary adjustment of the theodolite?
Difficulty: Medium
A. Centering, elimination of parallax, levelling and setting
B. Centering, setting, elimination of parallax and levelling
C. Setting, centering, levelling and elimination of parallax
D. Setting, levelling, elimination of parallax and centering
Correct Answer: C. Setting, centering, levelling and elimination of parallaxSolution:Each step builds on a stable foundation from the previous one: set up the tripod, centre over the mark, level using foot-screws, then focus to remove parallax.
Q42. The multiplying constant for the tacheometer is generally kept as:
Difficulty: Easy
Correct Answer: A. 100Solution:Manufacturers deliberately design the stadia hair spacing so K=f/i works out to 100, simplifying field distance calculations.
Q43. If the sum of northings of a traverse exceeds the sum of southings by 1 m and sum of eastings exceeds the sum of westings by 1 m, the resultant closing error and its true bearing are respectively:
Difficulty: Hard
A. 1.414 m, N 45 E
B. 1 m, N 45 E
C. 2 m, N 45 W
D. 2 m, N 45 E
Correct Answer: A. 1.414 m, N 45 ESolution:Closing error = √(1²+1²) = 1.414 m. Bearing = tan⁻¹(1/1) = 45°, in the NE quadrant since both errors are positive: N 45° E.
Q44. In an adjusted level when the bubble is central, the axis of the bubble tube becomes parallel to:
Difficulty: Easy
A. Line of sight
B. Line of collimation
C. Axis of the telescope
D. None of these
Correct Answer: A. Line of sightSolution:Centring the bubble confirms the line of sight is exactly horizontal — the fundamental working principle of any levelling bubble tube.
Q45. Size of a theodolite is specified by:
Difficulty: Easy
A. Diameter of lower plate
B. Diameter of upper plate
C. Length of telescope
D. Diameter of vertical circle
Correct Answer: A. Diameter of lower plateSolution:Theodolite “size” is conventionally specified by the diameter of the lower (scale) plate, e.g. a “120 mm theodolite.”
