Q1. In regard to the resection method of plane table survey, the term ‘resector’ refers to the:
Difficulty: Medium
A. rays from known station to un-plotted points
B. rays from un-plotted station to known points
C. rays from known station to known points
D. rays from un-plotted station to un-plotted points
Correct Answer: B. rays from un-plotted station to known pointsSolution:In resection, the instrument is at the unknown (un-plotted) station. Resectors are the rays drawn from that unknown position toward the already-plotted known control points a, b, c. Their intersection fixes the instrument position on the sheet.
Q2. In plane table surveying, Lehmann’s rules are associated with:
Difficulty: Easy
A. solution of all types of resection problems
B. method of resection after orientation by compass
C. method of resection by two-point problem
D. method of resection by three-point problem
Correct Answer: D. method of resection by three-point problemSolution:Lehmann’s trial-and-error method is specifically associated with the three-point problem. The surveyor draws three resection rays; if they form a triangle of error, Lehmann’s rules specify where inside the triangle the true station lies. Repeated until the triangle vanishes.
Q3. In plane table surveys, the orientation of the table only by back-sighting is preferred when:
Difficulty: Medium
A. the traverse is too long
B. speed is more important than accuracy
C. the plane table can be set on a point already plotted on the sheet
D. there is no second point for orientation
Correct Answer: C. the plane table can be set on a point already plotted on the sheetSolution:Back-sighting requires a previously plotted station. When the current setup is on a plotted point, back-sighting to the previous station gives accurate geometric orientation. Option D (no second point) is when a compass must be used instead.
Q4. Method 1: Point O is plotted by measuring only distances MO and NO. Method 2: Point O is plotted by measuring only angles ∠NMO and ∠MNO. Which of these methods also represents the principle of trigonometrical levelling?
Difficulty: Hard
A. Neither Method 1 nor Method 2
B. Method 2 only
C. Both Method 1 and Method 2
D. Method 1 only
Correct Answer: B. Method 2 onlySolution:Method 2 fixes a point using angular measurements only, without measuring the distance to the target — exactly the principle of trigonometrical levelling and triangulation. Method 1 is distance-based (chain survey principle).
Q5. With respect to plane table surveying, the terms ‘triangle of error’, ‘great circle’, and ‘great triangle’ are related to:
Difficulty: Medium
A. Lehmann method
B. Bessel method
C. two-point problem
D. graphic triangulation
Correct Answer: A. Lehmann methodSolution:All three terms belong to Lehmann’s trial-and-error method for the three-point problem. Great triangle = triangle of the three known points; Great circle = circumscribed circle through them; Triangle of error = small triangle formed by imperfectly converging resection rays.
Q6. When only one point is available for orientation, orientation is done by:
Difficulty: Easy
A. fore-sighting
B. back-sighting
C. intersection
D. trough compass
Correct Answer: D. trough compassSolution:Back-sighting needs a plotted back-station. When only one reference point is available (or none), the trough compass aligns the table to magnetic north, providing orientation independently of geometric references.
Q7. Which of the following is a disadvantage of plane table survey?
Difficulty: Easy
A. It replaces compass survey in magnetic areas.
B. It is essentially a tropical instrument.
C. It is most suitable for small scale maps.
D. It is simple and cheaper than a theodolite survey.
Correct Answer: B. It is essentially a tropical instrument.Solution:Options A, C, D are all advantages. Being “essentially a tropical instrument” is the standard textbook disadvantage: open-air plotting on paper cannot be done in rain, strong wind, or humid cold climates, limiting the method to dry, tropical conditions.
Q8. In setting up a plane table at station A, the point on the plan was NOT accurately centred. If displacement of A was 20 cm at right angles to the ray, how much is the displacement on the plan? (Scale: 1 cm = 2 m)
Difficulty: Hard
A. 2 mm
B. 0.4 mm
C. 1 mm
D. 0.03 mm
Correct Answer: C. 1 mmSolution:R.F. = 1 cm / 2 m = 1/200. Displacement on plan = 20 cm × (1/200) = 0.1 cm = 1 mm.
Q9. The principle of plane table survey is:
Difficulty: Easy
A. Traversing
B. Ranging
C. Parallelism
D. Triangulation
Correct Answer: C. ParallelismSolution:The governing principle is parallelism: all rays on the drawing sheet must be parallel to the corresponding lines on the ground. This is maintained by correct orientation of the table at every station.
Q10. Which of the following represents the CORRECT order of setting up a plane table?
Difficulty: Medium
A. Centering, levelling and orientation
B. Centering, orientation and levelling
C. Levelling, centering and orientation
D. Levelling, orientation and centering
Correct Answer: C. Levelling, centering and orientationSolution:Always Level first (table must be horizontal before centering works), then Center (plumbing fork over peg), then Orient (rotate to align sheet with ground). Levelling adjustment disturbs centering; centering adjustment disturbs orientation. Hence: Level → Center → Orient.
Q11. What is the purpose of conducting the resection method in plane table surveying?
Difficulty: Easy
A. To determine the location of the instrument
B. To plot the details
C. To survey hilly region
D. To survey plain region
Correct Answer: A. To determine the location of the instrumentSolution:Resection establishes the position of the occupied but unknown instrument station on the sheet. Plotting details = radiation; hilly areas = intersection. Resection answers “where am I?”
Q12. What is the function of the plumbing fork in plane table surveying?
Difficulty: Easy
A. Used for centering of plane table
B. Used for levelling the plane table
C. Used for orientation of plane table
D. Used for sighting the object
Correct Answer: A. Used for centering of plane tableSolution:The U-shaped plumbing fork holds its upper arm on the station mark of the sheet while a plumb bob hangs from the lower arm. When the plumb bob is directly above the ground station peg, centering is achieved. (Levelling = spirit level; Orientation = compass/back-sight; Sighting = alidade.)
Q13. Which of the following errors is most likely to occur in plane table surveying?
Difficulty: Easy
A. Error in sighting
B. Error in orientation
C. Error in levelling
D. Error in measurement
Correct Answer: B. Error in orientationSolution:Orientation must be established correctly at every station. Even a small angular error affects all rays drawn from that setup simultaneously, and errors accumulate through the traverse. Orientation error is thus both the most frequent and most impactful error in plane table surveying.
