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Past Questions
Detachment of soil particles is maximum, when the depth of overland flow is between:
A)
1/5 and 1/3 of drop diameter
B)
1/5 and 1/3 of soil’s particle’s diameter
C)
Both (a) & (b)
D)
0.15 to 0.20mm
In the study of soil erosion, specifically rainsplash erosion, the detachment of soil particles is influenced by the interaction between falling raindrops and the existing layer of overland flow (sheet flow). When there is no water on the surface, the raindrop's energy is absorbed directly by the soil. When the water depth is very high, the water acts as a cushion, absorbing the impact energy. Research in soil mechanics and hydrology indicates that the maximum detachment of soil particles occurs when the depth of the overland flow is between 1/5 and 1/3 of the diameter of the falling raindrop. At this specific depth, the impact energy is optimally transmitted to the soil particles to dislodge them, while the flow is sufficient to transport them away, but not deep enough to fully cushion the impact. Option (b) is incorrect because soil particle diameter is far too small to be the governing factor for raindrop impact energy. Option (d) is a specific measurement that does not account for the variability in raindrop sizes.
There are 25 girls in a row. Hannah was shifted by three places towards her right side and she occupies the middle position in the row. What was her original position from the left end?
A)
15th
B)
16th
C)
12th
D)
10th
Option A is correct: 15th.
For a dumpy level in perfect adjustment, the horizontal cross hair should be in a plane________.
A)
parallel to vertical axis
B)
parallel to axis of bubble tube
C)
perpendicular to vertical axis
D)
None of these
In a dumpy level, 'perfect adjustment' refers to the condition where the instrument is correctly calibrated so that the line of sight is truly horizontal when the bubble is centered. For this to occur, the following geometric relationships must hold: 1. The vertical axis must be truly vertical. 2. The line of collimation (the line passing through the cross-hairs) must be perpendicular to the vertical axis. 3. The horizontal cross-hair must be in a plane that is perpendicular to the vertical axis. If the horizontal cross-hair were not perpendicular to the vertical axis, the line of sight would tilt as the instrument is rotated, leading to errors in leveling. Therefore, the horizontal cross-hair must lie in a plane perpendicular to the vertical axis to ensure a consistent horizontal plane of sight.
Kirpich formula estimates the time of concentration (Tc) as:
A)
T = 0.02((L3 / H)1/2 )0.77
B)
T = 0.02L0.77 S -0.385
C)
Tc = 0.02(LS) -0.385
D)
Tc = 0.02(LS)0.77
The Kirpich formula is a widely used empirical equation in hydrology to estimate the Time of Concentration (Tc), which is the time required for water to travel from the hydraulically most distant point of a watershed to the outlet. The standard form of the Kirpich equation is: Tc = 0.0195 * L^0.77 * S^-0.385, where Tc is the time of concentration in hours, L is the length of the main channel in miles, and S is the average slope of the channel in ft/mile. In many textbooks and exam contexts, the coefficient 0.0195 is rounded to 0.02. Therefore, the formula is expressed as Tc = 0.02 * L^0.77 * S^(-0.385).
Analyzing the options:
- Option (a) is mathematically incorrect and does not follow the Kirpich derivation.
- Option (b) matches the standard empirical form: T = 0.02 * L^0.77 * S^(-0.385).
- Option (c) and (d) incorrectly group L and S together inside the parentheses, which changes the mathematical relationship (the exponents must apply to L and S independently).
A pedometer is most useful for measuring:
A)
Height of a building
B)
Long distances flown
C)
Depth of water
D)
Short walking distances
A pedometer is an electromechanical apparatus that counts the number of steps taken by a person. In surveying, this is used for 'pacing,' where the distance is calculated by multiplying the number of steps by the average length of a single pace.
1. Why 'd' is correct: Pedometers are specifically designed to track steps during walking, making them suitable for estimating short to medium walking distances where high precision is not required (reconnaissance surveys).
2. Why 'a' is incorrect: Height of a building is measured using instruments like theodolites, total stations, or clinometers (trigonometric leveling).
3. Why 'b' is incorrect: Distances flown are measured using GPS, inertial navigation systems, or radar altimeters.
4. Why 'c' is incorrect: Depth of water is measured using sounding leads, echo sounders, or bathymetric sensors.
One hectare is equal to:
A)
1,000 m²
B)
10,000 m²
C)
100,000 m²
D)
1 km²
A hectare (symbol: ha) is a non-SI metric unit of area used primarily for measuring land. By definition, one hectare is equal to the area of a square with sides of 100 meters.
Calculation:
Area = Length × Width
Area = 100 m × 100 m = 10,000 m².
Analysis of other options:
- Option (a) 1,000 m² is only one-tenth of a hectare.
- Option (c) 100,000 m² is equal to 10 hectares.
- Option (d) 1 km² is equal to 1,000 m × 1,000 m = 1,000,000 m², which is equal to 100 hectares.
For accurate weir measurement, the nappe should be:
A)
Aerated and free
B)
Clinging
C)
Submerged
D)
Turbulent
In hydraulic structures, a weir is used to measure the flow rate of water in an open channel. The 'nappe' is the sheet of water that flows over the crest of the weir. For the standard discharge equations (like the Francis formula) to be accurate, the nappe must be 'free' and 'aerated'.
1. **Free Nappe**: This means the water falls freely from the crest without being obstructed or pushed back by downstream water (which would cause 'submergence').
2. **Aerated Nappe**: Air must be allowed to circulate under the nappe. If air is not present, a partial vacuum forms between the nappe and the weir face, which sucks the nappe downward (causing it to 'cling'). This vacuum changes the flow characteristics and leads to an inaccurate (higher) reading of the head over the weir, thereby introducing errors in the discharge calculation.
Why other options are incorrect:
- **Clinging (b)**: A clinging nappe occurs when air is not supplied under the nappe, leading to inaccurate measurements due to the vacuum effect.
- **Submerged (c)**: A submerged nappe occurs when the downstream water level rises above the crest, reducing the flow rate for a given head and requiring a correction factor.
- **Turbulent (d)**: Turbulence in the approach flow or the nappe itself introduces instability and measurement errors.
A Parshall flume consists of three main components. Which of the following is NOT one of them?
A)
Converging section
B)
Filtering section
C)
Throat section
D)
Diverging section
A Parshall flume is a specially shaped open channel used for measuring the flow rate of water or wastewater. It is designed to create a critical flow condition, allowing the discharge to be calculated based on a single head measurement. It consists of three distinct geometric components:
1. Converging section: The inlet part where the channel narrows, accelerating the flow.
2. Throat section: The narrowest part of the flume where the flow reaches critical depth.
3. Diverging section: The outlet part where the channel widens to slow the flow and recover some of the energy loss.
A 'Filtering section' is not a component of a Parshall flume; filtering is a separate water treatment process and is not part of the hydraulic geometry used for flow measurement in a flume.
The level at which the water stands in a well before pumping starts is called:
A)
Piezometric surface
B)
Pumping water level
C)
Initial water level
D)
Static water level
In groundwater hydrology, the 'Static Water Level' (SWL) is defined as the level of water in a well when the water is in equilibrium with the surrounding aquifer, specifically before any pumping begins or after the water level has recovered following a pumping period.
Here is why the other options are incorrect:
- a. Piezometric surface: This refers to the imaginary surface to which water would rise in a piezometer; while the static water level in a well reflects the piezometric surface of the aquifer, the specific term for the level inside the well is the static water level.
- b. Pumping water level: This is the level to which the water drops during the actual process of pumping (also known as the dynamic water level).
- c. Initial water level: While descriptive, this is not the standard technical term used in hydrology and engineering textbooks.
Therefore, the correct technical term for the water level before pumping starts is the Static Water Level.
In which condition of Froude number, a strong hydraulic jump takes place:
A)
F 9.0
B)
F 7.0
C)
F = 4.5 – 9.0
D)
F = 1.7 – 2.5
A hydraulic jump is a phenomenon where a supercritical flow transforms into a subcritical flow, resulting in a significant loss of energy. The nature and classification of the jump depend on the upstream Froude number (Fr). According to the standard classification of hydraulic jumps (often attributed to USBR - United States Bureau of Reclamation):
1. Undular Jump: 1.0 < Fr < 1.7
2. Weak Jump: 1.7 < Fr < 2.5
3. Oscillating Jump: 2.5 < Fr < 4.5
4. Steady Jump: 4.5 < Fr < 9.0
5. Strong Jump: Fr > 9.0
In a 'Strong Jump', the turbulence is very high, and the energy dissipation is significant. Therefore, a strong hydraulic jump takes place when the Froude number is greater than or equal to 9.0.
Analysis of options:
- Option (a) F 9.0: Correct, this defines a Strong Jump.
- Option (b) F 7.0: Incorrect, as the range 4.5 to 9.0 is categorized as a Steady Jump.
- Option (c) F = 4.5 – 9.0: Incorrect, this is a Steady Jump.
- Option (d) F = 1.7 – 2.5: Incorrect, this is a Weak Jump.
Where will the centre of gravity of a uniform rod lie?
A)
At its middle point
B)
At its end
C)
At the centre of its cross-sectional area
D)
Depends upon its material
The centre of gravity (CG) is the point through which the entire weight of a body acts, regardless of its orientation. For a body with a uniform distribution of mass (homogeneous material) and a symmetrical shape, the centre of gravity coincides with its geometric centre (centroid). A 'uniform rod' implies that the mass per unit length is constant throughout its length. For a straight rod of length L, the geometric centre is located at L/2, which is the middle point of the rod.
Why other options are incorrect:
- Option b: The end of the rod is not the balance point; the rod would rotate if supported there.
- Option c: The centre of the cross-sectional area describes the axis of the rod, but not the specific point along the length where the total weight is concentrated.
- Option d: Since the rod is specified as 'uniform', the material is consistent throughout; therefore, the CG depends on the geometry, not the specific type of material used.
Silica in excess causes:
A)
The cement to set slowly
B)
The cement to set quickly
C)
The cement to expand
D)
The cement to disintegrate
In the chemical composition of Portland cement, silica (SiO2) is a primary constituent that provides strength through the formation of calcium silicate hydrates (C-S-H gel). However, the balance of ingredients is critical for the setting time. An excess of silica (SiO2) in the cement composition acts as a retarder, which slows down the hydration process and consequently causes the cement to set more slowly. Conversely, an excess of alumina (Al2O3) or iron oxide (Fe2O3) typically accelerates the setting process (causing it to set quickly). Expansion and disintegration are generally caused by excess lime (CaO) or the presence of magnesium oxide (MgO) and sulfates, not by excess silica.
The moment diagram for a cantilever beam whose free end is subjected to a bending moment, will be:
A)
Parabola
B)
Triangle
C)
Rectangle
D)
Cubic parabola
To determine the shape of the bending moment diagram (BMD), we analyze the internal moment at any section of the beam.
1. **Beam Setup**: Consider a cantilever beam of length 'L' fixed at one end and free at the other. A concentrated bending moment 'M' is applied at the free end.
2. **Internal Moment Calculation**: Let 'x' be the distance from the free end. The internal bending moment at any section 'x' is the sum of the moments acting to one side of that section. In this case, the only external load is the moment 'M' applied at the end.
3. **Equation**: The bending moment M(x) at any point x along the beam is constant: M(x) = M.
4. **Geometric Interpretation**: Since the value of the bending moment is the same at every cross-section from the free end to the fixed support, the plot of the bending moment against the length of the beam is a horizontal straight line.
5. **Diagram Shape**: A constant value plotted over a length results in a rectangular area between the baseline (beam axis) and the moment value line.
Comparison with other options:
- **Parabola**: Occurs when the beam is subjected to a Uniformly Distributed Load (UDL).
- **Triangle**: Occurs when the beam is subjected to a concentrated point load at the end.
- **Cubic Parabola**: Occurs when the beam is subjected to a uniformly varying load (UVL).
The most economical section of grass water way is:
A)
Parabolic
B)
Rectangular
C)
Triangular
D)
Trapezoidal
The most economical grass waterway section is the **parabolic** section. For a given cross-sectional area, a parabolic channel provides the least wetted perimeter, which means minimum boundary contact and therefore minimum resistance to flow. This makes it the most hydraulically efficient and economical shape for grassed waterways.
Why the others are incorrect:
- **Rectangular**: has a larger wetted perimeter for the same area, so it is less economical.
- **Trapezoidal**: commonly used in channels, but it is not as efficient as the parabolic section for grass waterways.
- **Triangular**: has even more wetted perimeter relative to area and is generally the least economical among these options.
Hence, the correct answer is **a) Parabolic**.
The IS Code for concrete mix design is:
A)
IS 1893
B)
IS 4990
C)
IS 10262
D)
IS 13920
The correct IS Code for the mix design of concrete is IS 10262. This code provides the guidelines and procedures for determining the proportions of cement, water, fine aggregate, and coarse aggregate to achieve a desired strength and durability.
Analysis of other options:
- IS 1893: This code deals with 'Criteria for Earthquake Resistant Design of Structures'.
- IS 4990: This is not a primary standard for concrete mix design (often confused with other material specifications).
- IS 13920: This code specifies the 'Ductile Design and Detailing of Reinforced Concrete Structures Subjected to Seismic Forces'.
Centrifugal pumps are used for pumping water when:
A)
Both head and discharge are high
B)
Discharge is high and head is low
C)
Both discharge and head are low
D)
Discharge is low and head is high
Centrifugal pumps are kinetic energy pumps that convert rotational energy from an impeller into hydrodynamic energy of the fluid. Their operational characteristics are defined by their performance curves: they are designed to handle large volumes of liquid (high discharge) but are limited in the amount of pressure or height (head) they can generate compared to positive displacement pumps.
1. Why Option (b) is correct: Centrifugal pumps are most efficient when moving a high volume of water against a relatively low to medium head. This makes them ideal for applications like irrigation, water supply, and drainage.
2. Why Option (a) is incorrect: For both high head and high discharge, multiple centrifugal pumps are often placed in series and parallel, or specialized high-pressure pumps are used, as a single standard centrifugal pump cannot efficiently achieve both extremes.
3. Why Option (c) is incorrect: While they can operate at low head and discharge, this is not the primary reason or the optimal condition for which they are specifically 'used' or selected over other pump types.
4. Why Option (d) is incorrect: For low discharge and high head, positive displacement pumps (like reciprocating pumps) are used because centrifugal pumps would require an impractical number of stages to reach very high heads while maintaining low flow.
In the casing of a centrifugal pump, the kinetic energy of the water is converted into:
A)
Potential energy
B)
Pressure energy
C)
Heat energy
D)
Centrifugal moment.
In a centrifugal pump, the impeller rotates at high speed, imparting kinetic energy (velocity) to the water. As the water leaves the impeller and enters the pump casing (specifically the volute casing), the cross-sectional area of the flow path gradually increases. According to Bernoulli's principle, as the velocity of the fluid decreases due to the increasing area, the kinetic energy is converted into pressure energy. This increase in pressure allows the pump to lift the water to the required height or deliver it to a specific destination.
- Option (a) Potential energy: While the pump eventually provides head (potential energy), the immediate conversion within the casing is from kinetic to pressure energy.
- Option (c) Heat energy: This is a result of friction and turbulence (losses), not the intended purpose of the casing.
- Option (d) Centrifugal moment: This is a force/torque concept related to the impeller's rotation, not a form of energy conversion in the casing.
A cavity-type tube well is generally preferred when:
A)
The water-bearing stratum is very thick.
B)
Water is available only through the sides.
C)
A strong clay layer exists to support the pipe.
D)
The sand particles are very fine
A cavity-type tube well (also known as a cavern well) is a specialized type of well used in specific geological conditions. In these wells, a cavity is created in the water-bearing stratum, and the well pipe is placed within this cavity. This design is specifically preferred when the aquifer consists of very fine sand or silty sand. In such cases, standard screen slots would be too large (allowing sand to enter the well) or too small (causing excessive friction loss and clogging). By creating a cavity and using a gravel pack or a specific filter arrangement, the fine particles are kept out while allowing water to flow freely into the well.
Analysis of other options:
- Option (a): Thick strata do not necessitate a cavity-type well; standard tube wells are typically used for thick aquifers.
- Option (b): Water entering through the sides is a characteristic of almost all tube wells (radial flow), not a specific reason to choose a cavity-type design.
- Option (c): A strong clay layer is generally an aquiclude (impermeable) and is not the primary reason for implementing a cavity-type design, which focuses on the permeability and grain size of the aquifer itself.
Rearrange the parts of the sentence in correct order: P. often determines the success of collective efforts; Q. effective leadership; R. by aligning individual goals; S. with shared vision and purpose
A)
QPRS
B)
PQRS
C)
QRPS
D)
RPQS
To solve this sentence rearrangement problem, we must identify the subject, the verb, and the logical flow of the modifiers.
1. **Identify the Subject**: Part Q ('effective leadership') is a noun phrase that serves as a logical subject for the sentence.
2. **Identify the Verb/Predicate**: Part P ('often determines the success of collective efforts') contains the verb 'determines' and completes the main clause. Combining Q and P gives us: 'Effective leadership often determines the success of collective efforts.'
3. **Identify the Modifier/Method**: Parts R ('by aligning individual goals') and S ('with shared vision and purpose') explain *how* leadership determines success.
4. **Logical Sequence of Modifiers**: Part R introduces the method ('by aligning...'), and Part S provides the specific means of that alignment ('with shared vision and purpose'). Therefore, R must precede S.
Putting it all together: 'Effective leadership (Q) often determines the success of collective efforts (P) by aligning individual goals (R) with shared vision and purpose (S).'
Comparing this to the options:
- a. QPRS: Correct sequence.
- b. PQRS: Incorrect; starts with a verb phrase, lacking a subject.
- c. QRPS: Incorrect; 'effective leadership by aligning individual goals often determines...' is grammatically awkward and breaks the flow of the predicate.
- d. RPQS: Incorrect; starts with a prepositional phrase and places the subject in the middle.
The velocity-area method of measuring flow in a river involves:
A)
Dividing the stream into sections, measuring area and velocity for each, and summing the discharge.
B)
Measuring the total volume of the river.
C)
Using a tracer to measure the concentration.
D)
Measuring only the maximum velocity.
The velocity-area method is a fundamental technique in hydraulics used to determine the discharge (Q) of an open channel or river. The basic formula is Q = A × V, where A is the cross-sectional area and V is the average velocity. Because velocity varies across the width and depth of a river (due to friction at the banks and bed), the stream is divided into several vertical sections (sub-areas). For each section, the area is calculated and the velocity is measured (typically using a current meter). The total discharge is then the sum of the discharges of all individual sections: Q = Σ (ai × vi).
Why other options are incorrect:
- Option b: Measuring total volume is impractical for a flowing river and describes a static volume, not a flow rate (discharge).
- Option c: Using a tracer describes the 'Dilution Method' or 'Chemical Method', not the velocity-area method.
- Option d: Measuring only the maximum velocity would lead to a significant overestimation of the total flow, as velocity is not uniform across the section.
Select the correctly spelled word:
A)
Exhilerate
B)
Exhilarate
C)
Exelerate
D)
Exhalerate
The word 'exhilarate' is a verb meaning to make someone feel very happy, animated, or elated.
Step-by-step analysis of the options:
1. Option (a) 'Exhilerate' is incorrect because it uses an 'e' instead of an 'a' in the third syllable.
2. Option (b) 'Exhilarate' is the correct spelling. It follows the standard English orthography derived from the Latin 'exhilaratus'.
3. Option (c) 'Exelerate' is incorrect; it appears to be a misspelling of either 'exhilarate' or 'accelerate'.
4. Option (d) 'Exhalerate' is incorrect; it incorrectly blends the word 'exhale' with 'exhilarate'.
Scale is defined as:
A)
The fixed ratio that every distance on the plan bears with corresponding distance on the ground.
B)
The fixed ratio that every distance on the ground bears with corresponding distance on the plan
C)
The difference between the distance on the plan to the actual distance on the ground.
D)
The measurement of distance on the ground.
In surveying and cartography, 'Scale' is defined as the ratio of a distance on a map or plan to the corresponding actual distance on the ground. Mathematically, it is expressed as: Scale = (Distance on Map) / (Distance on Ground).
- Option (a) is correct because it accurately describes this ratio (Map Distance : Ground Distance).
- Option (b) is incorrect because it describes the inverse of the scale (Ground Distance : Map Distance), which is known as the 'Scale Factor' or simply the reciprocal of the scale.
- Option (c) is incorrect because scale is a ratio (division), not a difference (subtraction).
- Option (d) is incorrect because the measurement of distance on the ground is simply 'ground distance' or 'actual distance', not the scale.
Spacing of check dams normally ranges from:
A)
30 to 60 m
B)
50 to 100 m
C)
150 to 200 m
D)
200 to 250 m
Check dams are small, temporary or permanent structures constructed across a swale, drainage ditch, or intermittent stream to reduce water velocity, prevent soil erosion, and encourage groundwater recharge. The spacing between check dams is determined by the slope of the terrain and the desired ponding depth. In standard hydraulic and soil conservation engineering practices, the spacing is typically designed such that the toe of the pond created by one dam is just above the crest of the next dam to prevent scouring. For typical slopes found in hilly or agricultural terrains where check dams are most common, the standard spacing normally ranges from 50 to 100 meters. Option (a) is generally too close for standard check dams (more typical of very steep gully plugs), while options (c) and (d) are too far apart to effectively control velocity and prevent erosion in most runoff-prone areas.
Fuller’s rule is primarily used to determine the:
A)
optimum water cement ratio for maximum strength
B)
ideal grading of aggregates to achieve maximum density
C)
setting time of cement paste in concrete
D)
proportion of fine aggregate in mortar
Fuller's Rule (also known as the Fuller-Thompson curve) is a mathematical formula used in concrete technology to determine the optimal particle size distribution (grading) of aggregates. The primary objective of this rule is to achieve the maximum packing density of the aggregate skeleton. By filling the voids between larger particles with smaller particles, the amount of cement paste required to fill the remaining gaps is minimized, which leads to increased strength, reduced shrinkage, and better economy.
Analysis of other options:
- Option (a) is incorrect because the water-cement ratio is governed by the Abrams' Law, not Fuller's rule.
- Option (c) is incorrect because setting time is determined by chemical reactions and tested using the Vicat apparatus.
- Option (d) is incorrect because the proportion of fine aggregate is typically determined by mix design methods (like IS code or ACI methods) based on the volume of coarse aggregates, not specifically by Fuller's rule alone.
Hooke’s law states that stress is directly proportional to strain within:
A)
Plastic range
B)
Elastic limit
C)
Strain hardening zone
D)
Necking zone
Option B is correct: Elastic limit.