← Legal Metrology
Past Questions
Best irrigation canal generally aligned along
A)
valley line
B)
contour line
C)
ridge line
D)
straight line
In irrigation engineering, the alignment of a canal is critical for maximizing the area of command.
1. Ridge Line (Watershed Line): A ridge canal is aligned along the highest point of the land (the ridge line). The primary advantage of this alignment is that it allows for irrigation of land on both sides of the canal by gravity. This maximizes the 'command area' and minimizes the need for expensive pumping or lifting mechanisms.
2. Valley Line: Aligning a canal along a valley line (the lowest point) is generally avoided because the water would only be able to irrigate the land on the higher slopes above the canal, requiring lifting. Furthermore, valley lines are prone to flooding and drainage issues.
3. Contour Line: A contour canal follows a constant elevation. While useful for traversing slopes, it typically only irrigates land on one side (the downhill side), reducing the potential command area compared to a ridge canal.
4. Straight Line: A straight line ignores the topography of the land. If a canal is forced into a straight line across varying terrain, it would require excessive cutting and filling (earthwork) and would not optimize the gravity-based distribution of water.
Therefore, the ridge line is the best alignment for maximizing the efficiency and coverage of an irrigation system.
For standing crops in undulating sandy fields, the best method of irrigation is
A)
free flooding
B)
check flooding
C)
furrow method
D)
sprinkler irrigation
To determine the best irrigation method, we must analyze the two key constraints provided in the question: 'undulating fields' and 'sandy soil'.
1. Undulating Fields: In fields with uneven topography (undulating), surface irrigation methods like free flooding, check flooding, and furrow irrigation are inefficient. Water tends to accumulate in the low-lying areas (causing waterlogging) and fails to reach the higher elevations, leading to uneven water distribution.
2. Sandy Soil: Sandy soils have high infiltration rates and low water-holding capacity. In surface irrigation, water seeps rapidly into the ground, requiring massive amounts of water to move the wetting front across the field, which leads to significant water wastage.
Analysis of Options:
- Free Flooding (a) and Check Flooding (b): These require a level land surface to ensure uniform distribution. On undulating land, they are highly inefficient.
- Furrow Method (c): While better than flooding for some crops, it still requires a specific slope and is inefficient in sandy soils due to high deep percolation losses.
- Sprinkler Irrigation (d): This is a pressurized system that mimics rainfall. It is independent of the land's topography (making it ideal for undulating fields) and allows for precise application of water, which minimizes the deep percolation losses associated with sandy soils.
Therefore, sprinkler irrigation is the most technically and economically viable method for these specific conditions.
According to Railway Board, diamond crossing should be flatter than
A)
1 in 16
B)
1 in 12
C)
1 in 8.5
D)
1 in 6
In railway engineering, a diamond crossing is a configuration where two tracks cross each other at a grade. The 'flatness' of the crossing refers to the angle of the crossing. According to the standards set by the Railway Board (and common permanent way manuals), the angle of the crossing should be as shallow (flat) as possible to ensure safety and reduce wear and tear on the wheels and rails. Specifically, it is stipulated that diamond crossings should be flatter than 1 in 8.5. If the crossing is steeper than this (e.g., 1 in 6), it increases the impact forces and the risk of derailment, necessitating a significant reduction in speed. Therefore, 1 in 8.5 is the standard threshold for these installations.
If Cd, Cv and Cc are the coefficients of discharge, coefficient of velocity and coefficient of contraction of an orifice then
A)
Cd = Cv . Cc
B)
Cv = Cd . Cc
C)
Cc = Cv . Cd
D)
Cc = Cd / Cv
In fluid mechanics, when liquid flows through an orifice, the actual discharge is less than the theoretical discharge due to energy losses and the contraction of the jet. Three coefficients are defined to account for these effects:
1. **Coefficient of Discharge (Cd)**: The ratio of the actual discharge (Qa) to the theoretical discharge (Qt).
Formula: Cd = Qa / Qt
2. **Coefficient of Velocity (Cv)**: The ratio of the actual velocity (Va) to the theoretical velocity (Vt). It accounts for energy losses due to friction.
Formula: Cv = Va / Vt
3. **Coefficient of Contraction (Cc)**: The ratio of the area of the jet at the vena contracta (Aa) to the area of the orifice (Ao).
Formula: Cc = Aa / Ao
Mathematically, the actual discharge is the product of the area of the jet and the actual velocity:
Qa = Aa * Va
The theoretical discharge is the product of the area of the orifice and the theoretical velocity:
Qt = Ao * Vt
Dividing the two equations:
Cd = (Aa * Va) / (Ao * Vt)
Cd = (Aa / Ao) * (Va / Vt)
Cd = Cc * Cv
Therefore, the relationship is Cd = Cv * Cc. Option (a) is correct, while options (b), (c), and (d) are mathematically incorrect rearrangements of this fundamental fluid mechanics identity.
On the recommendation of Indian Road Congress, the ruling gradient in plains, is
A)
1 in 10
B)
1 in 15
C)
1 in 20
D)
1 in 30
In highway engineering, the 'Ruling Gradient' is the maximum gradient a road can have such that vehicles can climb it without a significant loss of speed. The Indian Road Congress (IRC) specifies different ruling gradients based on the terrain:
1. Plain Terrain: The ruling gradient is 1 in 30 (3.33%).
2. Rolling Terrain: The ruling gradient is 1 in 20 (5%).
3. Mountainous Terrain: The ruling gradient is 1 in 20 (5%).
4. Steep Terrain: The ruling gradient is 1 in 15 (6.67%).
Since the question specifically asks for the ruling gradient in 'plains', the correct value is 1 in 30. Options a, b, and c refer to steeper gradients used in more challenging terrains (Steep, Mountainous/Rolling, and Rolling respectively).
In groundwater, relation of volume of void Vv in soil mass to the total volume Vt is called
A)
coefficient of permeability
B)
porosity
C)
coefficient of transmissibility
D)
storage coefficient
Step-by-step reasoning:
1. Definition of Porosity: In soil mechanics and hydrology, porosity (n) is defined as the ratio of the volume of voids (Vv) to the total volume (Vt) of the soil mass. Mathematically, n = Vv / Vt. It is usually expressed as a percentage or a decimal fraction.
2. Analysis of other options:
- (a) Coefficient of permeability (k): This refers to the ease with which a fluid can flow through a porous medium (hydraulic conductivity), not a volume ratio.
- (c) Coefficient of transmissibility (T): This is the product of the hydraulic conductivity (k) and the thickness of the aquifer (b), representing the rate at which water is transmitted through a unit width of the aquifer.
- (d) Storage coefficient (S): This is the ratio of the volume of water an aquifer releases from or takes into storage to the product of the surface area of the aquifer and the change in hydraulic head.
3. Conclusion: The specific relation described (Volume of voids / Total volume) is the exact definition of porosity.
In a centrifugal pump casing, flow of water leaving the impeller is
A)
rectilinear
B)
radial
C)
free vortex motion
D)
forced vortex motion
In a centrifugal pump, the impeller rotates and imparts kinetic energy to the water, forcing it to move outward from the center (eye) toward the periphery. As the water leaves the impeller vanes, it is discharged in a radial direction into the pump casing (volute or diffuser). The purpose of the casing is then to collect this radial flow and gradually convert the high kinetic energy (velocity) into pressure energy by increasing the flow area.
Why other options are incorrect:
- a. Rectilinear: The flow is curved and radial, not in a straight line.
- c. Free vortex motion: A free vortex occurs when fluid rotates without an external torque (like water going down a drain), where velocity is inversely proportional to the radius. This is not the primary flow characteristic at the impeller exit.
- d. Forced vortex motion: While the fluid inside the impeller is subjected to a forced vortex (driven by the impeller's rotation), the question specifically asks about the flow 'leaving' the impeller, which is the radial discharge into the casing.
Unit hydrograph theory was enunciated by
A)
L.K.Sherman
B)
R.E.Horton
C)
J.R.Philips
D)
E.J.Gumbel
The Unit Hydrograph (UH) theory was developed by L.K. Sherman in 1932. A unit hydrograph is defined as the direct runoff hydrograph resulting from one unit (e.g., 1 cm or 1 inch) of effective rainfall falling uniformly over a drainage basin for a specified duration. The theory is based on two primary assumptions: linearity (the runoff is proportional to the rainfall excess) and time invariance (the response of the watershed to a given rainfall is the same regardless of when it occurs).
Analysis of other options:
- R.E. Horton: Known for his work on infiltration and soil erosion (Horton's Infiltration Equation).
- J.R. Philips: Known for his contributions to infiltration theory and the Philip's infiltration model.
- E.J. Gumbel: Known for the Gumbel Distribution, which is widely used in extreme value analysis for flood prediction and hydrology.
The idea of utilizing hydraulic energy to develop mechanical had been first mooted by
A)
J.V.Poncelet
B)
G.Coriolis
C)
J.B.Francis
D)
L.A.Pelton and V.Kaplan
The development of hydraulic turbines evolved through the contributions of several pioneers. Jean-Victor Poncelet (J.V. Poncelet) is credited with the early conceptualization and the 'mooting' of the idea of utilizing hydraulic energy to develop mechanical power through the systematic application of fluid mechanics principles. While others like Francis, Pelton, and Kaplan developed specific types of turbines (the Francis turbine, Pelton wheel, and Kaplan turbine respectively) and Coriolis contributed to the understanding of fluid dynamics and energy, Poncelet's early theoretical work laid the groundwork for the conversion of water energy into mechanical work. In the context of historical fluid mechanics and hydraulic machinery textbooks, Poncelet is often cited as the one who first proposed the fundamental ideas of utilizing hydraulic energy for mechanical power.
Euler’s equation for motion of fluids is given by (Where Z is the datum head, p is the pressure intensity; V is the average velocity and ρ is the density of fluid)
A)
dρ/dp + gdZ + VdV = 0
B)
dp/ρ + gdZ + VdV = 0
C)
dρ/p + gdZ + VdV = 0
D)
ρdp + gdZ + VdV = 0
Euler's equation of motion is derived from Newton's Second Law (F = ma) applied to a fluid element. For an inviscid (frictionless) fluid, the forces acting on the fluid element are the pressure force and the gravitational force.
1. Pressure Force: The net force due to pressure gradient is given by -dp/ρ (per unit mass).
2. Gravitational Force: The force due to gravity in the vertical direction is gdZ (where g is acceleration due to gravity and Z is the elevation head).
3. Acceleration: The convective acceleration of the fluid is given by VdV.
According to Euler's equation for steady, one-dimensional flow along a streamline:
(dp/ρ) + g dZ + V dV = 0
Integrating this equation leads to the Bernoulli Equation: (p/ρ) + gZ + (V²/2) = Constant.
Analyzing the options:
- Option (a) and (c) incorrectly place density (ρ) in the numerator of the pressure term.
- Option (d) incorrectly multiplies pressure by density instead of dividing by it.
- Option (b) correctly represents the pressure gradient term as dp/ρ, the potential energy term as gdZ, and the kinetic energy term as VdV.
The process of keeping the plane table into a fixed direction so that a line representing a direction on the ground is
A)
centering
B)
orientation
C)
levelling
D)
resection
In plane table surveying, 'Orientation' is the process of setting the table such that the lines drawn from a point on the paper are parallel to the corresponding lines on the ground. This ensures that the map is aligned correctly with the true directions of the terrain.
Here is why the other options are incorrect:
- Centering (a): This is the process of setting the point on the paper exactly over the corresponding station on the ground using a plumbing fork.
- Levelling (c): This is the process of making the table top perfectly horizontal using a spirit level.
- Resection (d): This is a method used to establish the location of the plane table station on the map by sighting known points, rather than a process of aligning the table's direction.
A floating body has the stable equilibrium if the metacentre M of the body lies
A)
much above the C.G of the body
B)
much below the C.G of the body
C)
on the C.G of the body
D)
all the above
In fluid mechanics, the stability of a floating body depends on the relative positions of the Center of Gravity (G) and the Metacentre (M).
1. **Stable Equilibrium**: A floating body is in stable equilibrium if the metacentre (M) is located above the center of gravity (G). In this case, the metacentric height (GM = distance from G to M) is positive. When the body is tilted, the buoyancy force creates a restoring couple that pushes the body back to its original upright position.
2. **Unstable Equilibrium**: If the metacentre (M) is below the center of gravity (G), the metacentric height (GM) is negative. Any tilt will create an overturning couple, causing the body to capsize.
3. **Neutral Equilibrium**: If the metacentre (M) coincides with the center of gravity (G), the body remains in its new position after being tilted.
Therefore, for stable equilibrium, M must lie above G.
Hydrostatic pressure on a dam depends on its
A)
length
B)
breadth
C)
depth
D)
material
Hydrostatic pressure is the pressure exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity. The formula for hydrostatic pressure is P = ρgh, where 'P' is the pressure, 'ρ' (rho) is the density of the fluid, 'g' is the acceleration due to gravity, and 'h' is the depth (or height of the fluid column above the point).
1. Depth (h): As depth increases, the weight of the fluid above the point increases, leading to a linear increase in pressure. Therefore, hydrostatic pressure depends directly on depth.
2. Length and Breadth: These are dimensions of the dam structure. While they affect the total force (Total Force = Pressure × Area), they do not affect the pressure at a specific point.
3. Material: The material of the dam affects the dam's ability to withstand the pressure (strength/stability), but it does not influence the pressure exerted by the water itself.
Air vessel is essential in
A)
centrifugal pump
B)
reciprocating pump
C)
air lift pump
D)
submersible pump
An air vessel is a pressurized chamber containing air and liquid, used specifically in reciprocating pumps. Its primary functions are: 1) To reduce the pulsations in the delivery of liquid, ensuring a more uniform and continuous flow (smoothing the flow). 2) To reduce the acceleration head losses, which improves the overall efficiency of the pump. 3) To protect the piping system from hydraulic shocks (water hammer).
Comparing the options:
- Centrifugal pumps (a) provide a continuous flow by nature and do not require air vessels.
- Reciprocating pumps (b) are positive displacement pumps that deliver fluid in pulses; hence, air vessels are essential to stabilize the flow.
- Air lift pumps (c) use compressed air to lift water, but they do not use an 'air vessel' for flow smoothing in the same mechanical sense.
- Submersible pumps (d) are typically centrifugal and do not require air vessels.
A part of water from plants that goes in the sky to join the clouds is called
A)
evaporation
B)
transpiration
C)
interception
D)
none of the above
The question asks for the specific process by which water from plants enters the atmosphere.
1. **Transpiration (Option b):** This is the biological process where plants absorb water from the soil through their roots and release it as water vapor into the atmosphere through small pores in their leaves called stomata. This fits the description perfectly.
2. **Evaporation (Option a):** This is the general process where liquid water from surfaces (like oceans, lakes, or soil) changes into water vapor due to heat. While plants contribute to 'evapotranspiration', the specific part coming from the plant's biological activity is transpiration.
3. **Interception (Option c):** This occurs when precipitation (rain or snow) is caught by vegetation or buildings before it ever reaches the soil surface. It is a process of capturing water, not releasing it into the sky.
Therefore, the correct term for water leaving plants to join the clouds is transpiration.
φ-index, W-index, f index are some indices to measure
A)
rainfall
B)
infiltration
C)
evaporation
D)
transpiration
Same as above - infiltration indices.
Falling drops of water becomes sphere due to
A)
adhesion
B)
cohesion
C)
surface tension
D)
viscosity
The phenomenon where falling drops of water assume a spherical shape is primarily due to surface tension. Surface tension is the property of a liquid surface that causes it to behave like a stretched elastic membrane. This occurs because molecules at the surface experience a net inward cohesive force, pulling them toward the interior of the liquid. To minimize the potential energy of the system, the liquid naturally seeks to minimize its surface area for a given volume. Mathematically, a sphere is the geometric shape that has the minimum surface area for a fixed volume. Therefore, surface tension pulls the water drop into a spherical shape.
Why other options are incorrect:
- Adhesion: This is the attraction between molecules of different substances (e.g., water and glass). It does not cause a drop to become spherical in mid-air.
- Cohesion: While surface tension is a result of cohesive forces between similar molecules, 'surface tension' is the specific macroscopic property that describes the minimization of surface area. Cohesion is the cause, but surface tension is the mechanism/property that dictates the shape.
- Viscosity: This is the internal friction or resistance of a fluid to flow. It affects the speed of the fall and the deformation of the drop under air pressure, but it does not drive the drop toward a spherical shape.
International Civil Aviation Organisation (ICAO) was set up in Montreal in
A)
1950
B)
1947
C)
1939
D)
1929
The International Civil Aviation Organization (ICAO) is a specialized agency of the United Nations. It was established following the Convention on International Civil Aviation, which was signed in Montreal on December 7, 1944 (known as the Chicago Convention). However, the organization officially came into existence and began its operations on April 4, 1947, when the convention was ratified by a sufficient number of states. Therefore, 1947 is the correct year for its establishment. Option (a) 1950 is too late; Option (c) 1939 is before the Chicago Convention; and Option (d) 1929 is far too early.
For the movement of vehicles at the intersection of two roads, without any interference, the type of grade separation generally provided is
A)
delta
B)
clover leaf
C)
diamond interchange
D)
trumpet
The question asks for a grade separation that allows vehicles to move at the intersection of two roads 'without any interference'.
1. **Cloverleaf Interchange**: This is designed specifically for the intersection of two high-speed highways. It allows traffic to move from any direction to any other direction (including left and right turns) using a combination of overpasses, underpasses, and loop ramps. Because there are no traffic signals or stop signs required for the movements, it provides the highest level of 'non-interference' or continuous flow.
2. **Diamond Interchange**: While common, it typically involves at-grade intersections at the ends of the ramps, meaning vehicles must stop or yield (interference) to cross the minor road.
3. **Trumpet Interchange**: This is used where one road terminates into another (T-junction), not for the intersection of two continuous roads.
4. **Delta Interchange**: This is a simplified form of a T-junction interchange and does not provide full, non-interfering movement for two intersecting roads.
Therefore, the cloverleaf is the standard grade separation for providing continuous, non-interfering movement at the intersection of two roads.
The road foundation for modern highways construction was developed by
A)
Telford
B)
Macadam
C)
Tresguet
D)
Telford and Macadam simultaneously
The development of road foundations evolved through several key pioneers in the 18th and 19th centuries.
1. **Thomas Telford (Option a):** Telford is credited with developing the first systematic road foundation. His method involved placing a heavy foundation of large, hand-set stones (broken stones) at the bottom, which were then layered with smaller stones, creating a solid, stable base that could support heavy loads and provide effective drainage. This is considered the precursor to the modern engineered road foundation.
2. **John Loudon McAdam (Option b):** Macadam improved upon previous methods by focusing on the 'wearing course.' He argued that the natural soil (subgrade) could support the load if it was kept dry. He eliminated the heavy stone foundation used by Telford and instead used layers of small, angular broken stones that compacted under traffic to form a dense, water-resistant surface. While revolutionary, his method focused more on the surface/pavement than the deep foundation.
3. **Pierre-Marie-Jérôme Tresguet (Option c):** Tresguet was an early pioneer who used a foundation of large stones, but his methods were less widely adopted and refined than Telford's in the context of the evolution toward modern highway engineering.
Therefore, when referring specifically to the development of the 'road foundation' (the structural base), Telford's contribution is the most significant.
Model of river is
A)
simple model
B)
undistorted model
C)
distorted model
D)
all the above
In fluid mechanics, model laws are used to scale prototypes. A model is 'undistorted' if the scale ratio is the same for all linear dimensions (length, width, and depth). However, for river models, if an undistorted scale is used, the depth of the water in the model becomes extremely small, leading to excessive viscous effects (surface tension and boundary layer thickness) that dominate the flow and make the model unrealistic. To maintain a reasonable depth and ensure that the flow remains turbulent and representative of the prototype, the vertical scale (depth) is kept different from the horizontal scale (length and width). This practice of using different scales for different dimensions is known as 'distortion'. Therefore, river models are typically distorted models to ensure the validity of the hydraulic simulation.
The parameters (friction factor f, Reynolds number Re, roughness number D/k) plot diagram is called
A)
Moody’s diagram
B)
Stanton-Pannel diagram
C)
Reynolds diagram
D)
(a) and (b)
The plot relating the Darcy friction factor (f), the Reynolds number (Re), and the relative roughness (k/D or D/k) is most commonly known as the Moody's diagram. However, the Moody diagram is actually a synthesis of earlier experimental data and theoretical work. The Stanton-Pannel diagram (developed by Stanton and Pannel) was one of the primary precursors and equivalent representations used to determine the friction factor for turbulent flow in pipes based on the same parameters. In many advanced fluid mechanics contexts and older technical textbooks, both terms are recognized as referring to the graphical representation of these specific dimensionless parameters. Therefore, since both (a) and (b) describe this specific plot, option (d) is the most comprehensive answer.
If the degree of the curve (specified length 30m) is 153º, the radius of the curve is approximately
A)
573m
B)
382m
C)
1910m
D)
none of the above
1. Understanding the Definition: The 'degree of a curve' (D) is defined as the angle subtended at the center of the curve by an arc of a specified length (L). In this problem, the specified length L = 30m and the degree D = 153º.
2. Formula: The relationship between the radius (R), the arc length (L), and the central angle (D in degrees) is given by the formula:
L = (π * R * D) / 180
Rearranging to solve for R:
R = (L * 180) / (π * D)
3. Calculation:
L = 30 m
D = 153º
R = (30 * 180) / (3.14159 * 153)
R = 5400 / 480.66
R ≈ 11.23 m
4. Analysis of Options:
The calculated radius is approximately 11.23 meters. Comparing this to the given options:
a. 573m (Incorrect)
b. 382m (Incorrect)
c. 1910m (Incorrect)
Since the calculated value does not match any of the provided numerical options, the correct choice is 'none of the above'. Note: It is highly likely there is a typo in the question's degree value (e.g., if D was 1.53º, R would be 1123m; if D was 15.3º, R would be 112.3m), but based on the text provided (153º), the result is 11.23m.
Difference FB and BB of a line without local attraction is
A)
100º
B)
270º
C)
180º
D)
200º
In surveying, the Fore Bearing (FB) is the bearing of a line measured in the direction of the progress of the survey, and the Back Bearing (BB) is the bearing of the same line measured in the opposite direction. Mathematically, the relationship between the Fore Bearing and Back Bearing of a line is given by: Back Bearing = Fore Bearing ± 180°. Therefore, the absolute difference between the FB and BB of a line is |FB - BB| = 180°. This relationship holds true provided there is no 'local attraction' (interference from nearby magnetic objects) affecting the compass needle. If local attraction exists, the difference will deviate from 180°. Since the question explicitly states 'without local attraction', the difference is exactly 180º.
To avoid inconvenience to slow- moving vehicles, the maximum value of the centrifugal ratio on roads is generally taken as
A)
1/2
B)
1/4
C)
1/8
D)
1
In highway engineering, the centrifugal ratio is defined as the ratio of the centrifugal acceleration to the acceleration due to gravity (g). It is expressed as: Centrifugal Ratio = V² / (gR), where V is the speed of the vehicle and R is the radius of the curve.
When a road is super-elevated (banked) to counteract centrifugal force for fast-moving vehicles, slow-moving vehicles may experience a tendency to slide inward toward the center of the curve due to gravity. To prevent this inward sliding and to avoid inconvenience to slow-moving vehicles, the super-elevation (e) is limited. According to standard design guidelines (such as IRC), the maximum value of the centrifugal ratio (which corresponds to the maximum super-elevation e = V² / gR) is generally restricted to 0.07 (7%) for plain terrain or 0.10 (10%) for hilly terrain to ensure stability for slow vehicles.
Among the given options, 1/8 (which is 0.125) is the closest standard theoretical limit often cited in textbooks to represent the upper bound of the centrifugal ratio to maintain safety and comfort for slow-moving traffic, whereas 1/2, 1/4, and 1 are far too high and would cause slow vehicles to slide inward significantly.