Correct Answer: A. considering that the ranging rod is at correct position
Solution:
In chain surveying, specific hand signals are used for communication over distances. When the surveyor raises both hands and lowers them, it is the standard signal to indicate that the ranging rod is now correctly aligned on the survey line.
In chain/tape surveying, the 3-4-5 method can be used:
i. to set out a contour line
ii. to draw a perpendicular line to the chain line,
iii. to draw a perpendicular offset,
iv. to remove the obstacle to ranging.
Correct Answer: C. ii and iii
Solution:
The 3-4-5 method is a practical application of the Pythagorean theorem to create a right angle (90°). This is used to set out perpendicular lines from a chain line, which includes perpendicular offsets. It is not used for contours or obstacles.
Correct Answer: C. careless holding and marking
Solution:
Compensating errors are those that are liable to occur in either direction and tend to cancel out. Careless holding and marking can result in the measurement being slightly too long or too short, and these errors tend to average out over a long line. The other options are cumulative errors, which consistently affect the measurement in one direction.
Correct Answer: D. Measured length on sloped ground (Secδ - 1)
Solution:
Hypotenusal allowance is the correction applied to measurements along a slope to find the true horizontal distance. The correction is given by the formula: L(sec(δ) - 1), where L is the measured length along the slope and δ is the angle of the slope.
Correct Answer: D. The measured distance is 1600 cm less than the actual distance.
Solution:
This is a trick question. If the chain is longer than standard, the measured distance will be less than the actual distance. Correction per chain length = 0.2 m. Number of chain lengths = 2400m / 30m = 80. Total error = 80 * 0.2m = 16m = 1600cm. Since the chain was too long, the measured distance (2.4km) is shorter than the true distance. The error is negative, but the question asks for the relationship, which is that the measured distance is 1600 cm less than the actual distance.
i. Chain surveying is suitable for surveys of a small extent on open grounds to secure data for the exact description of the boundaries of a piece of land.
ii. The principle of chain surveying is triangulation.
Correct Answer: A. Both statements i and ii are correct
Solution:
Statement (i) correctly describes the ideal use case for chain surveying. Statement (ii) is also correct, as the core principle of chain surveying is to divide the area into a network of triangles, as triangles are geometrically stable shapes that can be defined by their side lengths alone.
Correct Answer: C. 351.4 m
Solution:
True Length = (Actual length of chain / Designated length of chain) * Measured length.
Actual length of chain = 30 m + 12 cm = 30.12 m.
True Length = (30.12 / 30) * 350 = 351.4 m.
Correct Answer: C. Chain length too long
Solution:
Error = Measured Value - True Value. If a chain is too long (e.g., 30.1m instead of 30m), it under-measures the true distance. The measured value will be less than the true value, resulting in a negative error. Sag and bad ranging lead to positive errors (measured value > true value). Temperature variation can be positive or negative.
Correct Answer: C. Adjustable cross-staff
Solution:
A standard cross-staff and optical square are used for setting out 90° angles. A French cross-staff can set out 45° and 90° angles. Only the adjustable cross-staff has a rotating upper cylinder that allows setting out any angle, making it suitable for oblique offsets.
Correct Answer: D. Obstacle to ranging but not chaining
Solution:
Reciprocal ranging (or indirect ranging) is specifically used when the two end points of a survey line are not intervisible (e.g., due to a hill or rise in the ground). This creates an obstacle to ranging (seeing from one end to the other), but it does not prevent chaining (measuring) along the ground.
Correct Answer: B. 2
Solution:
While standard indirect ranging procedures often involve four people for efficiency (one at each end station and two ranging in between), it is technically possible for two skilled surveyors to perform the operation by alternating positions, though it is much less common and more time-consuming.
Correct Answer: D. a triangle is the only simple figure that can be plotted from the length of its sides measured in the field.
Solution:
A triangle is a rigid, geometrically stable shape. Once the lengths of all three sides are known, its shape and size are uniquely determined. This allows for accurate plotting without needing to measure any angles, which is the fundamental concept of chain (linear measurement only) surveying.
Correct Answer: D. 49.96 m
Solution:
The correction for misalignment is always negative and is calculated using the formula C = -d² / (2L), where d is the distance out of line and L is the measured length.
C = -(2)² / (2 * 50) = -4 / 100 = -0.04 m.
True Length = Measured Length + Correction = 50 m - 0.04 m = 49.96 m.
Correct Answer: A. ±8 mm
Solution:
According to Indian Standard IS 1492:1970, the tolerance for a new 30-metre chain is ±8 mm. This standard ensures that survey equipment maintains a required level of accuracy for reliable measurements.
Correct Answer: A. Base line
Solution:
The base line is the longest and most important survey line in a chain survey. It forms the foundation of the survey's framework of triangles and is measured with the highest precision.