Chain and Plane Table Surveying
JKSSB Junior Engineer (Civil) · Surveying · 14 practice questions with answers and explanations: 10 Easy, 3 Medium, 1 Hard.
Sample questions
Sample Easy question 1
A well-conditioned triangle in chain surveying has angles that are:
- Greater than 150°
- Not less than 30° and not more than 120°
- All less than 20°
- Exactly 90°
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Answer: B. The best triangle is equilateral, which gives the most accurate plotting.
Sample Easy question 2
The alidade of a plane table is used to:
- Level the table
- Measure the distance
- Centre the table over the station
- Sight the objects and draw the rays
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Answer: D. A plain or telescopic alidade has a straight ruling edge.
Sample Easy question 3
The three temporary adjustments of a plane table at a station are:
- Levelling, centring and orientation
- Traversing, closing and adjusting
- Ranging, chaining and offsetting
- Collimation, levelling and focusing
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Answer: A. Orientation can be by a back ray or by a trough compass.
Sample Medium question 4
A 30 m tape that is 0.02 m too long measures 150 m. The true length is:
- 148.0 m
- 149.9 m
- 150.1 m
- 150.02 m
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Answer: C. True length = 150 × (30.02 ÷ 30) = 150.1 m.
Sample Medium question 5
A slope distance of 100 m is measured on a ground sloping at 5°. The horizontal distance is about:
- 99.62 m
- 100.38 m
- 95.0 m
- 99.9 m
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Answer: A. Horizontal distance = 100 × cos 5° = 99.62 m.
Sample Medium question 6
A 20 m chain is 0.05 m too short. A line measured as 400 m with it has a true length of:
- 401 m
- 399 m
- 400 m
- 399.95 m
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Answer: B. A short chain records too many chain lengths, so the true length is less: 400 × (19.95 ÷ 20).
Sample Hard question 7
Offsets of 0, 3.2, 4.0 and 2.8 m are taken at 5 m intervals from a chain line. The area by the trapezoidal rule is:
- 50 m²
- 43 m²
- 21.5 m²
- 86 m²
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Answer: B. Area = 5 × [(0 + 2.8) ÷ 2 + 3.2 + 4.0] = 43 m².