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Past Questions — 2010
The most popular and widely used theory of sediment in channel and stream is
A)
Brahms and Aiery’s theory
B)
Jaffrey’s lift concept theory
C)
White’s theory
D)
Shields’ tractive force theory
In fluvial hydraulics and sediment transport, the initiation of motion of particles on a bed is a critical concept. A.M. Shields developed the 'Tractive Force Theory' (also known as the Critical Shear Stress concept), which posits that sediment particles begin to move when the dimensionless shear stress (Shields parameter) exceeds a critical value. This theory is the most widely accepted and popular foundation for calculating the threshold of motion for bed load in streams and channels.
Comparing the options:
- Option (a) Brahms and Aiery: These are not recognized theories for sediment transport in hydrology.
- Option (b) Jaffrey’s lift concept: While lift forces are considered in sediment transport, Jaffrey's work is not the primary or most popular general theory for channel sediment.
- Option (c) White’s theory: While H.C. White contributed to fluid mechanics, there is no 'White's theory' that serves as the standard for sediment transport initiation.
- Option (d) Shields' tractive force theory: This is the industry and academic standard for determining the onset of sediment motion based on the balance between the tractive force of the flow and the resisting force of the particle's weight.
If the irrigation efficiency is 80%, conveyance losses is 20% and actual depth of watering is 16 cm, the depth of water to be supplied at the outlet is
A)
25 cm
B)
20 cm
C)
30 cm
D)
35 cm
Outlet depth = field depth / irrigation efficiency =16/0.8=20cm; with 20% conveyance loss source would need 25cm.
Choose the correct statement from the following
A)
Rivers, oceans, lakes and springs get water from rain
B)
Rain water is obtained by evaporation from lakes, oceans and lakes
C)
Water remains in atmosphere as vapours and clouds
D)
Hydrologic cycle is a continuous process of evaporation and precipitation of water in atmosphere
E)
all the above
The question asks to identify the correct statement regarding the hydrologic cycle. Let's analyze each option:
1. Option (a): Rivers, oceans, lakes, and springs are primary recipients of precipitation (rain/snow), which replenishes their water levels. This is a correct statement.
2. Option (b): Rain water originates from water vapor in the atmosphere, which is produced through the evaporation of water from oceans, lakes, and other water bodies. This is a correct statement.
3. Option (c): Water exists in the atmosphere in two primary forms: as an invisible gas (water vapor) and as liquid droplets or ice crystals (clouds). This is a correct statement.
4. Option (d): The hydrologic cycle is defined as the continuous movement of water on, above, and below the surface of the Earth, driven primarily by the processes of evaporation (and transpiration) and precipitation. This is a correct statement.
Since all statements (a, b, c, and d) are scientifically accurate descriptions of the hydrological process, the correct choice is 'all the above'.
The values or signs of latitude and departure of a line are both negative, Reduced bearing θ of the line is
A)
N θ W
B)
S θ E
C)
S θ W
D)
N θ W (duplicate)
In surveying, the latitude and departure of a line are the projections of the line on the North-South (meridian) and East-West axes, respectively.
1. **Latitude (L)**: This is the projection of the line on the North-South axis.
- If Latitude is positive (+), the line is moving towards the North.
- If Latitude is negative (-), the line is moving towards the South.
2. **Departure (D)**: This is the projection of the line on the East-West axis.
- If Departure is positive (+), the line is moving towards the East.
- If Departure is negative (-), the line is moving towards the West.
Given in the question:
- Latitude is negative (-) $\rightarrow$ Direction is South (S).
- Departure is negative (-) $\rightarrow$ Direction is West (W).
Therefore, the line lies in the third quadrant (South-West quadrant). The Reduced Bearing (RB) of a line in this quadrant is expressed as S $\theta$ W.
A simple manometer may be
A)
piezometer
B)
U-tube manometer
C)
single column manometer
D)
all the above
A manometer is a device used to measure the pressure of a fluid. Simple manometers are those that use a single column of liquid to measure pressure differences or absolute pressure.
1. Piezometer: This is the simplest form of a manometer. It consists of a simple glass tube connected to the point where pressure is to be measured. The height to which the liquid rises is directly proportional to the pressure.
2. U-tube Manometer: This consists of a U-shaped tube containing a manometric fluid. It is used to measure pressure differences between two points or the pressure of a gas/liquid relative to the atmosphere.
3. Single Column Manometer: This is a variation of the manometer (often including types like the inverted U-tube) where a single column of liquid is used to indicate the pressure change.
Since all three listed devices (piezometer, U-tube, and single column) fall under the category of simple manometers, the correct option is 'all the above'.
The provided road sign indicates
A)
one-way sign
B)
prohibited both ways
C)
no entry
D)
none of the above
Without figure, typical one-way sign question in MPSC uses arrow for one-way; assumed one-way sign (if figure shows no-entry would be C).
Extensively used levelling instrument is
A)
tilting level
B)
wye level
C)
dumpy level
D)
bubble tube
Step-by-step reasoning: 1. Analysis of the question: The question asks for the levelling instrument that is 'extensively used' in surveying practice. 2. Evaluating Option (a) Tilting Level: While accurate, it is more complex to set up and is used for specific high-precision work rather than general extensive use. 3. Evaluating Option (b) Wye Level: This is an older type of level where the telescope can be removed; it has been largely superseded by more stable designs. 4. Evaluating Option (c) Dumpy Level: The dumpy level is the most common, robust, and widely used instrument for general levelling tasks due to its simplicity, stability (the telescope is rigidly fixed to the vertical axis), and ease of operation. 5. Evaluating Option (d) Bubble Tube: A bubble tube is a component (a leveling accessory) used within a levelling instrument to establish a horizontal plane, not a standalone levelling instrument itself. Conclusion: The dumpy level is the standard, extensively used instrument for general engineering surveying.
If n is the total number of variables to describe a phenomenon, m is the number of fundamental quantities, then Buckingham π-theorem in dimensional analysis, expresses the resulting equation in terms of
A)
repeating variables
B)
n dimensionless parameters
C)
(n-m) dimensionless parameters
D)
none of the above
The Buckingham π-theorem is a fundamental principle in dimensional analysis used to determine the number of independent dimensionless groups (called π-terms) that can be formed from a set of variables.
1. Let 'n' be the total number of variables involved in the physical phenomenon (e.g., velocity, density, viscosity, diameter, etc.).
2. Let 'm' be the number of fundamental dimensions (primary quantities) required to describe these variables (e.g., Mass [M], Length [L], and Time [T]).
3. According to the theorem, the original relationship between the 'n' variables can be rewritten as a relationship between (n - m) independent dimensionless parameters.
Example: If a problem involves 5 variables (n=5) and 3 fundamental dimensions (m=3), the phenomenon can be described by (5 - 3) = 2 dimensionless parameters.
Analysis of options:
- Option (a) is incorrect because repeating variables are a tool used to derive the π-terms, not the final form of the equation.
- Option (b) is incorrect because it ignores the reduction provided by the fundamental dimensions.
- Option (c) is correct as it accurately states the mathematical result of the theorem: (n - m).
The river which is in the process of building up its own bed and certain slope due to excess sediment is called
A)
degrading river
B)
aggrading river
C)
virgin river
D)
stable river
In fluvial geomorphology and hydrology, the term 'aggradation' refers to the process of sediment accumulation in a river bed.
1. **Aggrading River (Option b):** This occurs when the sediment load carried by the river exceeds its transport capacity. As a result, the excess sediment is deposited on the river bed, causing the bed level to rise (building up its own bed) and altering the slope. This is the correct answer.
2. **Degrading River (Option a):** Degradation is the opposite of aggradation. It occurs when the river's transport capacity is greater than its sediment load, leading to erosion of the bed and a lowering of the bed level.
3. **Stable River (Option d):** A stable river (or a river in equilibrium) is one where the sediment load is exactly balanced by the transport capacity, meaning there is no net increase or decrease in the bed level over time.
4. **Virgin River (Option c):** This is not a standard technical term used to describe the sediment balance or bed-level changes of a river in hydrology; it usually refers to a specific geographic name or a river untouched by human intervention.
Triaxial shear test is preferred to direct shear test because
A)
stress distribution on the failure plane is not uniform
B)
it can be performed under all three drainage conditions with complete control
C)
precise measurement of the pore pressure and change in volume during test, is not possible
D)
none of the above
The Triaxial Shear Test is considered superior to the Direct Shear Test for several fundamental reasons in soil mechanics:
1. **Drainage Control (Option b):** In a triaxial test, the drainage valves can be opened or closed to simulate specific field conditions. This allows for Unconsolidated Undrained (UU), Consolidated Undrained (CU), and Consolidated Drained (CD) tests. In a direct shear test, drainage control is virtually impossible.
2. **Stress Distribution:** In a direct shear test, the stress distribution is non-uniform, and the failure plane is forced (predetermined) along the horizontal split of the box. In a triaxial test, the confining pressure is applied uniformly, and the soil fails along its weakest plane (the natural failure plane).
3. **Pore Pressure Measurement:** Triaxial tests allow for the precise measurement of pore water pressure (u), which is essential for calculating effective stress. Direct shear tests cannot measure pore pressure.
Evaluating the options:
- Option (a) describes a disadvantage of the direct shear test, but the phrasing 'stress distribution... is not uniform' as a reason why triaxial is preferred is slightly ambiguous; however, the primary technical advantage is drainage control.
- Option (b) is a definitive technical advantage of the triaxial test.
- Option (c) is factually incorrect because precise measurement of pore pressure and volume change IS possible in a triaxial test.
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 (Option b):** This is designed 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) without the need for traffic signals or stopping. The use of loop ramps and directional ramps ensures that there is no crossing of traffic streams (no interference), making it the ideal choice for continuous flow.
2. **Diamond Interchange (Option c):** While it provides grade separation for the main roads, the ramps typically intersect with the minor road at grade, requiring traffic signals or stop signs. This introduces 'interference'.
3. **Trumpet Interchange (Option d):** This is used where one road terminates into another (a T-junction), not for the intersection of two continuous roads.
4. **Delta Interchange (Option a):** This is a variation of a T-junction interchange and does not serve the purpose of a full four-way intersection of two roads without interference.
Therefore, the cloverleaf is the standard grade separation provided to eliminate interference at the intersection of two major roads.
Ground water occurs in different zones below ground level (GL). The zone just below the GL is
A)
zone of aeration
B)
capillary fringe
C)
unconfined aquifer
D)
pressure or confined aquifer
In hydrology, the subsurface is divided into distinct zones based on the saturation of the soil/rock pores.
1. **Zone of Aeration (Unsaturated Zone):** This is the layer immediately below the ground level (GL) and extending down to the water table. In this zone, the pore spaces contain both air and water. Because it is the topmost layer of the subsurface, it is the zone 'just below the GL'.
2. **Capillary Fringe:** This is a thin transition layer located immediately above the water table. Water is drawn upward from the water table by capillary action. While it is part of the aeration zone in a broad sense, it is specifically located at the bottom of that zone, not just below the GL.
3. **Unconfined Aquifer (Phreatic Zone):** This is the zone below the water table where all pore spaces are completely filled with water (saturated). It is located below the zone of aeration.
4. **Confined Aquifer (Pressure Aquifer):** This is a saturated zone trapped between two impermeable layers (aquitards/aquicludes), usually located much deeper in the subsurface.
Therefore, the zone immediately following the ground surface is the zone of aeration.
Laplace equation in 3-Dimensional flow through soil with general notations is
A)
∂²φ/∂x² + ∂²φ/∂y² + ∂²φ/∂z² = 0
B)
∂²h/∂x² + ∂²h/∂y² + ∂²h/∂z² = 0
C)
∂u/∂x + ∂v/∂y + ∂w/∂z = 0
D)
none of the above
In soil mechanics, the flow of water through a porous medium is governed by Darcy's Law. For a steady-state, incompressible flow in a homogeneous and isotropic soil, the continuity equation leads to the Laplace equation. The Laplace equation describes the distribution of the total hydraulic head (h) in the medium. Mathematically, for 3-dimensional flow, it is expressed as the sum of the second-order partial derivatives of the hydraulic head with respect to the spatial coordinates (x, y, and z) equaling zero: ∂²h/∂x² + ∂²h/∂y² + ∂²h/∂z² = 0.
Analysis of options:
- Option (a) uses φ, which typically denotes a potential function or stream function. While Laplace equations can be written for potential functions, in the specific context of soil mechanics flow nets and seepage, the primary variable is the hydraulic head (h).
- Option (b) is the standard form of the Laplace equation for 3D seepage in soil mechanics.
- Option (c) represents the Continuity Equation (divergence of velocity equals zero) for an incompressible fluid, not the Laplace equation.
- Option (d) is incorrect as option (b) is the standard representation.
The final setting of the plates of theodolite when taking a foresight is achieved by using the
A)
upper clamps screw
B)
upper tangent screw
C)
lower clamp screw
D)
lower tangent screw
In the operation of a transit theodolite, the process of sighting a target (whether it is a backsight or a foresight) involves two main steps: coarse adjustment and fine adjustment.
1. Coarse Adjustment: The upper clamp screw is loosened, and the telescope is rotated approximately toward the target. Once the telescope is nearly aligned, the upper clamp screw is tightened to lock the upper plate to the telescope.
2. Fine Adjustment (Final Setting): To achieve precise alignment with the target, the 'upper tangent screw' (also known as the slow-motion screw) is used. This screw allows for very small, controlled movements of the telescope, ensuring the cross-hairs are exactly centered on the target.
Why other options are incorrect:
- Upper clamp screw (a): This is used to lock or unlock the telescope for coarse rotation; it cannot provide the precision required for 'final setting'.
- Lower clamp screw (c): This locks the entire instrument (lower plate) to the tripod head; it is used during the initial centering and leveling, not for sighting a specific point.
- Lower tangent screw (d): This is used for the fine adjustment of the lower plate relative to the tripod, typically used during the initial orientation of the instrument, not for the final sighting of a foresight target.
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. It is used to determine the friction factor for fluid flow in pipes across laminar, transitional, and turbulent regimes. However, historically and technically, the Stanton-Pannel diagram is another name for a similar plot used to represent the same relationship between these parameters. Therefore, both 'Moody's diagram' and 'Stanton-Pannel diagram' refer to this specific graphical representation of fluid friction. Option (c) is incorrect because the Reynolds diagram typically refers to different concepts or the general study of flow regimes, not specifically the friction factor plot.
Model of river is
A)
simple model
B)
undistorted model
C)
distorted model
D)
all the above
In fluid mechanics, model scaling is categorized based on the scale ratios used for different dimensions.
1. **Undistorted Models**: These are models where the scale ratio is the same for all linear dimensions (length, width, and depth). This maintains geometric similarity.
2. **Distorted Models**: These are models where different scale ratios are used for different dimensions (e.g., the horizontal scale is different from the vertical scale).
**Application to River Models**: Rivers are typically very wide and shallow. If an undistorted model were used (e.g., a 1:100 scale), the depth of the water in the model would become extremely small (often just a few millimeters), leading to excessive surface tension effects and viscous forces that would dominate the flow, making the model physically inaccurate (violating Froude scaling). To prevent this and ensure that the flow remains representative of the prototype, the vertical scale (depth) is intentionally made larger than the horizontal scale. This process is called 'distortion'. Therefore, models of rivers, harbors, and estuaries are almost always distorted models.
In non-uniform steady gradually varied flow
A)
velocity varies gradually
B)
depth changes gradually
C)
discharge changes
D)
pressure changes gradually
In fluid mechanics, specifically open channel flow, flow is classified based on how parameters change with respect to time and space.
1. **Steady Flow**: The flow parameters (velocity, depth, etc.) at any point do not change with time. Therefore, the discharge (Q) remains constant throughout the reach, making option (c) incorrect.
2. **Non-Uniform Flow**: The flow parameters change from one section to another along the length of the channel.
3. **Gradually Varied Flow (GVF)**: This is a specific type of non-uniform flow where the depth of flow (y) changes slowly over a long distance. Because the depth changes gradually, the streamlines are nearly parallel, and the pressure distribution remains approximately hydrostatic.
Comparing the options:
- Option (a): While velocity does change, GVF is specifically defined by the gradual change in the water surface profile (depth).
- Option (b): This is the fundamental definition of GVF. The depth changes gradually over a long distance.
- Option (c): In steady flow, discharge is constant by definition.
- Option (d): While pressure changes, the defining characteristic of GVF is the gradual variation of the depth of flow.
Hydraulic jump is an example of
A)
steady gradually varied flow
B)
unsteady gradually varied flow
C)
rapidly varied flow
D)
uniform flow
A hydraulic jump occurs when a high-velocity supercritical flow transitions abruptly to a low-velocity subcritical flow, resulting in a sudden rise in the water surface level and significant energy dissipation through turbulence. In fluid mechanics, open channel flows are categorized based on how the depth changes over distance:
1. Uniform Flow: Depth remains constant along the channel.
2. Gradually Varied Flow (GVF): Depth changes slowly over a long distance (e.g., backwater curves).
3. Rapidly Varied Flow (RVF): Depth changes abruptly over a very short distance.
Since a hydraulic jump involves a sudden, abrupt change in depth and velocity over a short distance, it is a classic example of Rapidly Varied Flow (RVF). Options (a) and (b) are incorrect because the change is not gradual, and option (d) is incorrect because the depth is not constant.
The convexity is provided to the carriage way between the crown and the edge of the pavement, is known as
A)
camber
B)
super-elevation
C)
height of the pavement
D)
none of the above
1. Definition of Camber: Camber is the transverse slope provided to the road surface. It is the convexity provided to the carriageway from the crown (the highest point of the road) to the edges.
2. Purpose: The primary objective of providing camber is to drain rainwater from the road surface to the side drains, preventing water logging and protecting the pavement from water penetration, which would otherwise weaken the subgrade.
3. Analysis of other options:
- Super-elevation (Option b): This is the transverse slope provided on horizontal curves to counteract centrifugal force, tilting the road inward toward the center of the curve. It is not for drainage across the entire carriageway but for stability during turning.
- Height of the pavement (Option c): This refers to the vertical distance of the pavement surface from a datum or the thickness of the pavement layers, which is unrelated to the convexity for drainage.
Therefore, the convexity provided between the crown and the edge is specifically termed as 'camber'.
If F is the drag force, u is the free upstream velocity around a submerged body of projected area A and ρ is the density of the fluid then drag coefficient Cd is
A)
F / (ρu^2 A)
B)
F / (ρu^2 A/2)
C)
F / (ρu^2 A^2)
D)
none of the above
The drag force (F) acting on a body moving through a fluid (or a fluid flowing past a stationary body) is defined by the drag equation. The formula is: F = Cd * (1/2 * ρ * u^2) * A, where:
- F is the drag force
- Cd is the dimensionless drag coefficient
- ρ (rho) is the density of the fluid
- u is the free upstream velocity
- A is the projected frontal area of the body.
To find the expression for the drag coefficient (Cd), we rearrange the formula to solve for Cd:
Cd = F / (1/2 * ρ * u^2 * A)
This can be rewritten as: Cd = F / (ρu^2 A / 2).
Comparing this to the options:
- Option (a) F / (ρu^2 A) is incorrect because it misses the factor of 1/2 (dynamic pressure term).
- Option (b) F / (ρu^2 A/2) matches the derived formula exactly.
- Option (c) F / (ρu^2 A^2) is incorrect as the area A should be to the first power.
Rankine’s theory of active earth pressure assumptions are
A)
soil mass is homogenous, dry and cohesion less
B)
ground surface may be horizontal or inclined
C)
back of the wall is vertical and smooth
D)
all the above
Rankine's Theory of Earth Pressure is based on several simplifying assumptions to derive the active and passive pressure coefficients.
1. **Soil Properties (Option a):** Rankine assumed the soil is homogeneous (uniform properties throughout), dry (or saturated, but the basic theory starts with dry/cohesionless soil), and cohesionless (c = 0). This allows the use of the internal friction angle (φ) as the primary strength parameter.
2. **Ground Geometry (Option b):** The theory is applicable whether the ground surface is horizontal or inclined at an angle (β) to the horizontal.
3. **Wall Interface (Option c):** A critical assumption is that the back of the wall is perfectly smooth (no friction between the wall and the soil) and vertical. This ensures that the failure plane is planar and the resultant pressure acts horizontally.
Since all three statements (a, b, and c) are fundamental assumptions of Rankine's theory, the correct option is 'd'.
Air vessel is essential in
A)
centrifugal pump
B)
reciprocating pump
C)
air lift pump
D)
submersible pump
An air vessel is a closed chamber containing compressed air at the top and liquid at the bottom, used specifically in reciprocating pumps. Its primary functions are: 1) To reduce the acceleration head (pulsations) of the liquid, ensuring a more uniform and continuous flow at the delivery end. 2) To reduce the friction losses in the pipeline by smoothing out the velocity fluctuations. 3) To protect the pump and piping from hydraulic shocks (water hammer). In contrast, centrifugal pumps provide a continuous flow by nature and do not require air vessels. Air lift pumps operate on the principle of density difference using injected air, and submersible pumps are typically centrifugal or helical in design, neither of which utilizes an air vessel for flow smoothing.
If 1 litre of liquid weighs 9N, its specific weight is
A)
900 N/m3
B)
9000 N/m3
C)
90 N/m3
D)
9 N/m3
Step-by-step calculation:
1. **Identify Given Data**:
- Weight of the liquid (W) = 9 N
- Volume of the liquid (V) = 1 litre
2. **Convert Units to SI**:
- The standard unit for volume in Fluid Mechanics is cubic meters (m³).
- 1 m³ = 1000 litres
- Therefore, 1 litre = 1/1000 m³ = 0.001 m³
3. **Apply Formula for Specific Weight**:
- Specific weight (γ) is defined as the weight per unit volume of a substance.
- Formula: γ = Weight / Volume
- γ = 9 N / 0.001 m³
4. **Calculate Result**:
- γ = 9 * 1000 N/m³ = 9000 N/m³
Comparing this result to the options:
- Option (a) 900 N/m³ is incorrect (off by a factor of 10).
- Option (b) 9000 N/m³ matches our calculation.
- Option (c) 90 N/m³ is incorrect.
- Option (d) 9 N/m³ is incorrect (this is the weight of 1 litre, not the weight per cubic meter).
The causes of solid waste pollution are
A)
population increase
B)
affluence
C)
growth of technology
D)
all the above
Solid waste pollution is driven by several socio-economic and demographic factors:
1. Population Increase: As the number of people increases, the total volume of waste generated per unit of area increases proportionally, putting pressure on waste management systems.
2. Affluence: Higher income levels lead to increased consumption patterns. Affluent societies tend to purchase more packaged goods, luxury items, and disposable products, which significantly increases the amount of waste produced per capita.
3. Growth of Technology: While technology can help manage waste, it also creates new types of pollution. The rapid obsolescence of electronic devices (e-waste) and the invention of non-biodegradable materials like plastics and synthetic polymers are direct results of technological growth.
Since all three factors contribute significantly to the increase in solid waste, option 'd' is the correct choice.
Stagnation point is the point in flowing fluid where
A)
pressure is zero
B)
where velocity is zero
C)
total energy is maximum
D)
momentum of flow is zero
In fluid mechanics, a stagnation point is defined as a point in a flow field where the local velocity of the fluid is zero. This typically occurs when a flowing fluid hits a solid boundary perpendicularly (such as the nose of an aircraft or the center of a Pitot tube), causing the fluid to come to a complete stop. At this point, the kinetic energy of the fluid is converted into pressure energy, resulting in the 'stagnation pressure'.
Analysis of other options:
- Option (a): Pressure is not zero; in fact, pressure is typically at its maximum (stagnation pressure) at this point.
- Option (c): Total energy remains constant along a streamline (according to Bernoulli's principle for inviscid flow); it is not 'maximum' at the stagnation point, but rather the kinetic energy is converted to pressure energy.
- Option (d): While the velocity is zero (and thus momentum per unit volume is zero), the term 'momentum of flow' usually refers to the global property of the stream, and the defining characteristic of a stagnation point is specifically the zero velocity vector.