Q1. Which of the following statements is true regarding the compensator used in an electronic theodolite?
Difficulty: Medium
A. It compensates for the effect of tilt of the axis of the bubble tube
B. It compensates for the effect of horizontal axis tilt
C. It compensates for the effect of tilt of the line of sight
D. It compensates for the effect of vertical axis tilt
Correct Answer: D. It compensates for the effect of vertical axis tiltSolution:The compensator automatically corrects for residual vertical-axis tilt remaining after manual levelling. It does not address bubble tube, horizontal axis, or line-of-sight tilt — those are corrected through separate adjustments.
Q2. Which of the following statements regarding the vertical circle of a theodolite is correct?
Difficulty: Medium
A. The graduation circle is fixed, but the Vernier scale moves with the telescope
B. Both the graduation circle and the Vernier scale move with the telescope
C. Both the graduation circle and the Vernier scale are fixed, while the telescope moves
D. The Vernier scale is fixed, but the graduation circle moves with the telescope
Correct Answer: D. The Vernier scale is fixed, but the graduation circle moves with the telescopeSolution:The graduated circle is rigidly attached to the trunnion axis and rotates with the telescope, while the vernier/index on the fixed standard frame stays stationary — this relative motion is how a vertical angle is read.
Q3. The stadia method used in tacheometric surveys generally refers to measurements taken with a:
Difficulty: Easy
A. Tacheometer with variable stadia hair
B. Tacheometer with fixed stadia hair
C. Fixed elevation of point
D. Fixed staff reading
Correct Answer: B. Tacheometer with fixed stadia hairSolution:In the fixed hair (stadia) method, the stadia hair spacing never changes; the surveyor reads the staff intercept and applies D = KS + C. This is the opposite of the movable hair (subtense) method.
Q4. Identify the correct statements regarding theodolite.
i. The axis of the plate level must lie in a plane parallel to the vertical axis.
ii. The horizontal axis must be perpendicular to the vertical axis.
iii. The vertical circle vernier must read zero when the line of collimation is horizontal.
iv. The axis of the altitude level must be perpendicular to the line of collimation.
Difficulty: Hard
A. i, ii, iii and iv
B. Only i and iv
C. Only i and iii
D. Only ii and iii
Correct Answer: D. Only ii and iiiSolution:Statements ii and iii are correct. Statements i and iv swap “parallel” and “perpendicular” — the plate level axis should be perpendicular to the vertical axis, and the altitude level axis should be parallel to the line of collimation.
Q5. To measure vertical angles, the theodolite must be levelled with reference to:
Difficulty: Easy
A. The bubble tube on the plate level
B. The altitude bubble on the index frame
C. The altitude bubble on both the telescope and the index frame
D. The altitude bubble on the telescope
Correct Answer: B. The altitude bubble on the index frameSolution:Before reading a vertical angle, the altitude bubble mounted on the index frame must be centred so the vertical circle’s vernier zero is truly horizontal at that instant.
Q6. Which of the following options represents an INCORRECT relation between the fundamental axes of a theodolite?
Difficulty: Medium
A. The axis of the altitude level must be parallel to the line of collimation
B. The axis of the plate level must be perpendicular to the vertical axis
C. The axis of the striding level must be perpendicular to the transit axis
D. The trunnion axis must be perpendicular to the line of sight
Correct Answer: C. The axis of the striding level must be perpendicular to the transit axisSolution:The striding level checks whether the trunnion axis is level — for this check to work, its bubble axis must be parallel (not perpendicular) to the trunnion axis. The other three relations are genuinely correct.
Q7. A tacheometer was set at a station and the readings were taken on two points, which were 100 m and 150 m apart and had staff intercepts of 3.98 m and 5.98 m, respectively. If an externally focusing tacheometer was used, then the values of f, i and d could be:
Difficulty: Hard
A. f = 0.2 m, i = 12 mm, d = 30 cm
B. f = 0.3 m, i = 1.2 mm, d = 20 cm
C. f = 0.3 m, i = 12 mm, d = 20 cm
D. f = 0.3 m, i = 0.12 m, d = 20 cm
Correct Answer: C. f = 0.3 m, i = 12 mm, d = 20 cmSolution:Subtracting the two distance equations (100=K(3.98)+C, 150=K(5.98)+C) gives K = 25. Only option C gives f/i = 0.3/0.012 = 25.
Q8. Following are the data of an externally focusing telescope: Staff intercept 1.52 m, stadia hair interval 5 mm, distance between vertical axis and objective 120 mm, focal length of objective 0.3 m. The multiplying constant is:
Difficulty: Medium
A. 60
B. 24
C. 12.67
D. 2.5
Correct Answer: A. 60Solution:K = f/i = 300 mm / 5 mm = 60. Only focal length and stadia interval are needed; staff intercept and distance d play no role in computing K.
Q9. The least count of a theodolite is:
Difficulty: Easy
A. 1 second
B. 1 millisecond
C. 1 minute
D. 1 hour
Correct Answer: A. 1 secondSolution:Electronic theodolites resolve angles to 1 arc-second using precision optical/electronic encoders, far finer than the 20-second resolution of a standard vernier theodolite (see Q30).
Q10. Which of the following statements regarding an electronic theodolite fitted with a graduated circle encoded in an incremental system is INCORRECT?
Difficulty: Medium
A. The graduated circle is fixed and it does not move
B. Two photodiodes are placed perpendicular to each other over the graduated circle
C. One of the photodiodes is fixed and the other moves with the telescope
D. The graduated circle is made of glass
Correct Answer: B. Two photodiodes are placed perpendicular to each other over the graduated circleSolution:In an incremental encoder, one photodiode is fixed and the other moves with the telescope, both aligned along the same line to count pulses — not placed perpendicular to each other.
Q11. Study the given figure and identify the correct pairs with respect to different parts of the prismatic compass/theodolite.
Difficulty: Medium
A. 14-Agate cap, 13-Mirror, 15-Pivot, 11-Brake pin
B. 11-Agate cap, 13-Mirror, 14-Pivot, 15-Brake pin
C. 15-Agate cap, 13-Mirror, 14-Pivot, 11-Brake pin
D. 15-Agate cap, 13-Mirror, 11-Pivot, 14-Brake pin
Correct Answer: C. 15-Agate cap, 13-Mirror, 14-Pivot, 11-Brake pinSolution:Matching component to function: Agate cap (15, underside of needle), Mirror (13, near sighting vane), Pivot (14, fixed centre), Brake pin (11, lever-operated damping mechanism).
Q12. In theodolite, what will happen with respect to rotation of upper and lower plates, if the lower clamp is clamped and the upper clamp is unclamped?
Difficulty: Medium
A. Upper plate rotates on inner axis with relative motion between upper and lower plates
B. Both upper and lower plates rotate together
C. Lower plate rotates on outer axis with relative motion between upper and lower plates
D. Instrument can rotate without any motion between two plates
Correct Answer: A. Upper plate rotates on inner axis with relative motion between upper and lower platesSolution:With the lower clamp tight, the outer spindle (lower plate) is locked; loosening the upper clamp frees the inner spindle, so the upper plate (with telescope) rotates relative to the fixed lower plate — “upper motion.”
Q13. According to which method of balancing the traverse, is ‘the total error in latitudes and in departure distributed in proportion to the latitudes and departure of the sides’?
Difficulty: Medium
A. Graphical method
B. The axis method
C. Transit method
D. Bowditch’s method
Correct Answer: C. Transit methodSolution:The Transit rule distributes closing error proportional to each line’s own latitude/departure, used when angular measurements are more precise than linear ones — distinct from Bowditch’s rule, which uses line length.
Q14. For measurement of vertical angles through theodolite, the instrument should be levelled with reference to the _____ bubble and the _____ clamp that is used to rotate the telescope in the vertical plane.
Difficulty: Easy
A. foot-screw; lower plate
B. altitude; upper plate
C. spindle; vertical plate
D. altitude; vertical circle
Correct Answer: D. altitude; vertical circleSolution:Vertical angle measurement is referenced to the altitude bubble on the index frame, and the telescope is tilted/locked using the vertical circle clamp — distinct from the plate clamps used for horizontal angles.
Q15. Which of the following statements regarding measurement of horizontal angles by theodolite are correct?
i. Errors due to adjustments of line of collimation and the trunnion axis are eliminated by taking both face readings.
ii. Errors due to eccentricity of verniers and centres are eliminated by taking both face readings.
iii. Closing the horizon is a process related to reiteration method of measurement of horizontal angle.
iv. In closing the horizon process, the sum of angles must equal 540 degrees.
Difficulty: Hard
A. ii and iii
B. i and iii
C. ii and iv
D. i and iv
Correct Answer: B. i and iiiSolution:Statement i (face-left/face-right eliminates collimation and trunnion axis errors) and statement iii (closing the horizon belongs to the reiteration method) are correct. Statement ii is wrong (eccentricity needs repetition, not face readings), and iv is wrong (the horizon closes to 360°, not 540°).
