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Past Questions
The capacity range of a Small Hydel Project in India is:-
A)
Up to 1 MW
B)
Up to 10 MW
C)
Up to 25 MW
D)
Above 25 MW
In India, the Ministry of New and Renewable Energy (MNRE) defines the classification of hydroelectric projects based on their installed capacity to determine eligibility for subsidies, funding, and regulatory frameworks. The standard classification is as follows:
1. Micro Hydel: Up to 100 kW
2. Mini Hydel: Above 100 kW up to 2 MW
3. Small Hydel Project (SHP): Up to 25 MW
Therefore, any hydroelectric project with a capacity up to 25 MW is categorized as a Small Hydel Project. Options (a) and (b) represent subsets of small hydro (Micro and Mini), while option (d) refers to Large Hydroelectric Projects.
The minimum compressive strength of 1st class bricks should be:-
A)
75 kg/cm2
B)
90 kg/cm2
C)
100 kg/cm2
D)
120 kg/cm2
According to standard engineering specifications (and traditionally followed in Indian Standard codes for brick classification), bricks are categorized into classes based on their compressive strength.
1. First Class Bricks: These are high-quality bricks used for load-bearing walls. They must have a minimum compressive strength of 10.5 N/mm², which is approximately 105-120 kg/cm². In most competitive exam contexts and traditional textbooks, the standard minimum strength for a 1st class brick is cited as 105 kg/cm² or 120 kg/cm² depending on the specific regional code, but 10.5 N/mm² (approx 107 kg/cm²) is the baseline. Among the given options, 120 kg/cm² is the recognized standard for high-quality first-class bricks.
2. Second Class Bricks: These have a minimum compressive strength of 70-75 kg/cm² (approx 7 N/mm²).
3. Third Class Bricks: These have a minimum compressive strength of 35-40 kg/cm².
Comparing the options:
- Option (a) 75 kg/cm² corresponds to 2nd class bricks.
- Option (b) 90 kg/cm² is an intermediate value.
- Option (c) 100 kg/cm² is close but usually, the benchmark for 'First Class' in these specific exam patterns is set at 10.5 N/mm² or higher, often rounded to 120 kg/cm² in older textbooks.
- Option (d) 120 kg/cm² is the correct standard for the minimum strength of a first-class brick in this multiple-choice context.
To ensure maximum overall plant efficiency, the rated head should be equal to:-
A)
Design head
B)
Gross head
C)
Operating head
D)
Net head
In hydroelectric power plant engineering, the 'Design Head' is the specific head at which the turbine is designed to operate with maximum efficiency.
1. **Design Head (Correct):** The turbine blades and runner geometry are optimized for a specific head. When the rated head (the head at which the plant is rated for its nominal output) equals the design head, the turbine operates at its peak efficiency point on the performance curve, ensuring maximum overall plant efficiency.
2. **Gross Head:** This is the total vertical distance between the water level at the intake and the tailrace. It includes losses due to friction and bends in the penstock. A turbine cannot operate at the gross head because of these inevitable losses.
3. **Net Head:** This is the actual head available at the turbine inlet after subtracting hydraulic losses (head loss) from the gross head. While the turbine operates using the net head, the 'rated' specification for maximum efficiency is tied to the 'design' parameters of the machine.
4. **Operating Head:** This is the actual head available during a specific period of operation, which varies based on reservoir levels and flow rates. It is a variable value, whereas the rated head is a fixed specification.
The volume of water level stored between the full reservoir level and minimum pool level is:-
A)
Live storage
B)
Dead storage
C)
Reservoir
D)
Spillway
In reservoir engineering, the storage capacity is divided into different zones based on the water levels:
1. **Live Storage (Active Storage):** This is the volume of water stored between the Full Reservoir Level (FRL) and the Minimum Pool Level (MPL). This water is available for release through the outlets/turbines for useful purposes like irrigation or power generation.
2. **Dead Storage:** This is the volume of water stored below the Minimum Pool Level (MPL). This water cannot be released by gravity and is primarily intended to allow for sediment accumulation over the life of the project.
3. **Surcharge Storage:** This is the volume between the Full Reservoir Level (FRL) and the Maximum Water Level (MWL).
Since the question specifically asks for the volume between the full reservoir level and the minimum pool level, the correct term is Live Storage.
The most common type of turbine used in low-head, high-flow in Small Hydel Project is:-
A)
Pelton
B)
Francis
C)
Kaplan
D)
Turgo
Hydraulic turbines are selected based on the available head (vertical distance the water falls) and the flow rate.
1. **Kaplan Turbine (Option c):** This is an axial-flow reaction turbine with adjustable blades. It is specifically designed for low-head (typically below 30-40 meters) and high-flow conditions. Because it can handle large volumes of water at low pressure, it is the most common choice for low-head small hydel projects.
2. **Pelton Wheel (Option a):** This is an impulse turbine used for very high-head and low-flow conditions. It uses high-velocity jets of water to strike buckets.
3. **Francis Turbine (Option b):** This is a mixed-flow reaction turbine used for medium-head and medium-flow conditions. It is the most versatile turbine but is not the primary choice for specifically 'low-head' scenarios compared to the Kaplan.
4. **Turgo Turbine (Option d):** This is a variation of the Pelton wheel (impulse turbine) used for medium to high heads, though it can handle higher flow rates than a standard Pelton wheel, it is not suitable for low-head applications.
In preliminary survey of a road project in hilly region, cross sections are taken generally at:-
A)
30 m
B)
40 m
C)
50 m
D)
60 m
In road surveying, cross-sections are taken perpendicular to the centerline to determine the earthwork (cutting and filling) and the width of the road. The interval for taking these cross-sections depends on the terrain:
1. In plain terrain, cross-sections are typically taken at larger intervals (e.g., 30m to 60m or more) because the ground is relatively uniform.
2. In hilly or undulating terrain, the ground surface changes rapidly. To ensure accuracy in volume calculations and to capture the steep slopes and irregularities of the terrain, cross-sections must be taken at shorter, more frequent intervals.
Among the given options, 30 m is the smallest interval provided. In hilly regions, the standard practice for preliminary surveys is to use the shortest available interval to minimize errors in earthwork estimation. Therefore, 30 m is the most appropriate choice compared to 40 m, 50 m, or 60 m.
Number of standard bricks required for 1 m3 is:-
A)
700
B)
600
C)
500
D)
550
To calculate the number of bricks required for 1 m³ of brickwork, we consider the standard size of a modular brick and the thickness of the mortar joints.
1. **Standard Modular Brick Size**: The standard size of a modular brick is 19 cm x 9 cm x 9 cm.
2. **Size with Mortar**: When bricks are laid in masonry, a mortar joint (typically 10 mm or 1 cm) is added to the length, width, and height. Therefore, the nominal size of one brick becomes: (19+1) cm x (9+1) cm x (9+1) cm = 20 cm x 10 cm x 10 cm.
3. **Volume of one brick with mortar**: 0.20 m x 0.10 m x 0.10 m = 0.002 m³.
4. **Calculation for 1 m³**:
Number of bricks = Total Volume / Volume of one brick with mortar
Number of bricks = 1 m³ / 0.002 m³ = 500 bricks.
However, in practical field conditions, there is a wastage factor (usually around 5-10%) and variations in brick sizes. For standard non-modular bricks (traditional sizes like 23 cm x 11.5 cm x 7.5 cm) or when accounting for wastage in standard engineering estimates, the value typically ranges between 500 and 550. In the context of most competitive exams for Junior Engineers, 500 is the theoretical modular count, but 550 is often cited as the standard requirement for 1 m³ of brickwork including wastage and mortar adjustments for traditional standard bricks. Given the options provided, 500 is the theoretical modular answer, but 550 is the widely accepted practical standard for 'standard bricks' in many regional codes.
The type of turbine used in Small Hydel Project for a water head range of 70 meter – 500 meter is:-
A)
Pelton
B)
Kaplan
C)
Francis
D)
Propeller
Hydraulic turbines are selected based on the available head (the vertical distance the water falls) and the flow rate.
1. **Pelton Wheel (Impulse Turbine):** These are designed for high-head applications. Typically, they are used for heads ranging from 300 meters up to 2000 meters, but in the context of small hydel projects and standard classification, they are the primary choice for heads exceeding 200-300 meters. For the range of 70m to 500m, as the head increases toward the upper limit (500m), the Pelton turbine becomes the most efficient and viable option.
2. **Francis Turbine (Reaction Turbine):** These are medium-head turbines. They typically operate in the range of 30 meters to 300 meters. While there is an overlap with the 70m-500m range, the upper limit of 500m strongly pushes the requirement toward an impulse turbine like the Pelton.
3. **Kaplan and Propeller Turbines (Reaction Turbines):** These are axial-flow turbines designed for low-head applications, typically below 30-50 meters, with very high flow rates.
Given the specific upper limit of 500 meters mentioned in the question, the Pelton turbine is the most appropriate selection for high-head energy conversion.
The key factor in determining the power output of a Small Hydel Project is:-
A)
The size of the penstock
B)
The type of turbine used
C)
The head and flow rate of water
D)
The material of the dam
The power output of any hydroelectric project, including Small Hydel Projects (SHP), is fundamentally determined by the potential energy of the water. The theoretical power (P) is calculated using the formula: P = ρ × g × Q × H × η, where:
1. ρ (rho) is the density of water,
2. g is the acceleration due to gravity,
3. Q is the flow rate (discharge) in cubic meters per second,
4. H is the net head (the vertical distance the water falls),
5. η (eta) is the efficiency of the system.
Since ρ and g are constants, the power output is directly proportional to the product of the Head (H) and the Flow Rate (Q).
Why other options are incorrect:
- Option (a): The size of the penstock affects the friction losses (head loss), but it does not determine the available power potential of the site.
- Option (b): The type of turbine is selected *based* on the head and flow rate to maximize efficiency, but the turbine itself does not create the power; it only converts the existing potential energy into mechanical energy.
- Option (d): The material of the dam is a structural/civil engineering consideration for stability and cost, and has no direct impact on the power generation formula.
The mix ratio for M-20 grade of concrete is:-
A)
1:1.5:3
B)
1:2:4
C)
1:3:6
D)
1:2:6
In concrete technology, the grade of concrete (e.g., M-20) refers to the characteristic compressive strength of a 150mm cube at 28 days (M stands for Mix and 20 stands for 20 N/mm²). For nominal mixes (standard proportions used for small-scale works), the ratios are defined as follows:
1. M-20 Grade: The nominal mix ratio is 1:1.5:3 (1 part Cement : 1.5 parts Fine Aggregate/Sand : 3 parts Coarse Aggregate).
2. M-15 Grade: The nominal mix ratio is 1:2:4 (Option b).
3. M-10 Grade: The nominal mix ratio is 1:3:6 (Option c).
4. Option d (1:2:6) is not a standard nominal mix for these common grades.
Therefore, for M-20 grade concrete, the correct proportion is 1:1.5:3.
Strength of cement concrete primarily depends upon:-
A)
Quality of water
B)
Quantity of aggregate
C)
Quantity of cement
D)
Water-cement ratio
The strength of concrete is primarily governed by the 'Abrams' Law', which states that for a given water-cement ratio, the strength of the concrete is independent of the amount of cement used, provided the mix is workable. The water-cement (w/c) ratio is the ratio of the weight of water to the weight of cement used in the concrete mix. A lower w/c ratio generally leads to higher strength and lower permeability because it reduces the volume of capillary pores formed when excess water evaporates from the hardened cement paste.
Why other options are incorrect:
- a. Quality of water: While water quality is important to prevent contamination or premature setting (e.g., avoiding salts or organic matter), it does not 'primarily' determine the strength level.
- b. Quantity of aggregate: Aggregates act as fillers and provide stability; while their grading and quality matter, they do not dictate the fundamental strength of the cement paste matrix.
- c. Quantity of cement: Increasing the quantity of cement without adjusting the water content does not necessarily increase strength; in fact, if the w/c ratio remains high, the strength will remain low regardless of the cement volume.
Which of the following is not a requirement for site selection of Small Hydel Project?
A)
Availability of water
B)
Large catchment area
C)
Sedimentation
D)
Rocky land
To determine the correct answer, we must analyze the specific requirements for a 'Small Hydel Project' (SHP) compared to large-scale hydroelectric dams.
1. **Availability of water (Option a):** This is a fundamental requirement for any hydel project. Without a consistent flow or volume of water, power generation is impossible.
2. **Large catchment area (Option b):** This is NOT a requirement for Small Hydel Projects. SHPs are typically 'run-of-river' projects or utilize small streams/canals. They are designed to operate with the available natural flow of a small stream and do not require a massive catchment area or a large reservoir, which are characteristics of Large Hydel Projects.
3. **Sedimentation (Option c):** While sedimentation is a problem, 'considering sedimentation' is a critical requirement for site selection. A site with excessive siltation would lead to turbine erosion and reservoir filling, making it unsuitable. Therefore, analyzing sedimentation is a requirement.
4. **Rocky land (Option d):** Rocky terrain is highly desirable for site selection because it provides a strong foundation for the weir, intake structures, and powerhouse, and it reduces the risk of seepage and landslides.
Since a large catchment area is only necessary for large-scale storage projects and not for small-scale projects, option (b) is the correct answer.
The characteristic used to define the grade of concrete is:-
A)
Tensile strength
B)
Compressive strength
C)
Density
D)
Neutral axis
In concrete technology, the 'grade' of concrete refers to its strength class. According to standard codes (such as IS 456:2000), the grade of concrete is denoted by the letter 'M' (which stands for Mix) followed by a number. This number represents the characteristic compressive strength of 150 mm cubes at 28 days, measured in N/mm². For example, M25 concrete has a characteristic compressive strength of 25 N/mm².
Why other options are incorrect:
- a. Tensile strength: Concrete is naturally weak in tension; while it is measured (often as split tensile strength), it is not used to define the grade.
- c. Density: Density relates to the weight of the concrete (e.g., lightweight or heavyweight concrete) but does not define the structural grade.
- d. Neutral axis: This is a geometric concept in structural analysis (the axis where there is no longitudinal stress) and is not a material property used for grading concrete.
The minimum diameter of steel in Column is:-
A)
12 mm
B)
10 mm
C)
16 mm
D)
20 mm
According to IS 456:2000 (the Indian Standard code of practice for Plain and Reinforced Concrete), which governs RCC design in India and is the standard for MPSC exams, the minimum diameter of longitudinal reinforcement bars in a column is specified to ensure structural stability and prevent buckling of the bars. Specifically, Clause 26.5.3.1 states that the minimum diameter of longitudinal reinforcement bars shall be 12 mm.
- Option (a) 12 mm: Correct, as per IS 456:2000.
- Option (b) 10 mm: Incorrect; this is often used for stirrups or ties, but not for main longitudinal reinforcement in columns.
- Option (c) 16 mm: Incorrect; while 16 mm is commonly used, it is not the minimum requirement.
- Option (d) 20 mm: Incorrect; this is a standard bar size but not the minimum requirement.
Penstocks are opened or closed conduits that carry water to the:-
A)
Forebay
B)
Power channel
C)
Turbines
D)
Reservoir
In a hydroelectric power plant, the penstock is a high-pressure pipeline that conveys water from the reservoir or forebay down to the turbines. Its primary purpose is to convert the potential energy of the stored water into kinetic energy by directing it at high velocity and pressure onto the turbine blades to rotate the generator.
Why other options are incorrect:
- a. Forebay: The forebay is the basin that stores water immediately before it enters the penstock; the penstock starts from the forebay, it does not carry water to it.
- b. Power channel: The power channel (or headrace canal) is used to transport water from the intake to the forebay; it precedes the penstock in the system.
- d. Reservoir: The reservoir is the primary storage source at the highest elevation; water flows from the reservoir toward the turbines, not the other way around.
The slope of stair should not exceed:-
A)
300
B)
400
C)
350
D)
450
In the context of building materials and construction standards for stairs, the 'slope' refers to the ratio of the rise to the run (tread). While the options are presented as numbers (300, 400, 350, 450), in engineering exam nomenclature for this specific topic, these typically represent ratios or degrees. For general residential and public buildings, the recommended slope of a staircase is usually between 25° and 40°. A slope exceeding 40° (represented here as 400 or 40 degrees in some shorthand notations used in departmental exams) is considered too steep for safe and comfortable movement. Therefore, the slope should not exceed 40°. Option (b) 400 corresponds to the 40° limit commonly cited in building codes for standard stairs.
The common feature in hill road is:-
A)
U turn
B)
Hair pin bend
C)
Speed limit
D)
Landslide
In Transportation Engineering, specifically in the design of hill roads, a 'Hair pin bend' is a characteristic feature used to gain elevation in steep terrain where the slope is too great for a straight road. It is a sharp curve (usually 180 degrees) that allows the road to 'fold' back on itself to climb a mountain.
Reasoning for other options:
- a. U turn: While similar in shape, a U-turn is a maneuver used to reverse direction on a road, whereas a hair pin bend is a permanent structural design element of the road alignment.
- c. Speed limit: Speed limits exist on all types of roads (plain, urban, highway), so it is not a feature specific or unique to hill roads.
- d. Landslide: A landslide is a natural disaster or a geological hazard that may occur on hill roads, but it is not a 'feature' of the road design; it is a failure of the slope.
The structure that allows overflow of water to the downstream side when the reservoir is full is called:-
A)
Power channel
B)
Penstock
C)
Spillway
D)
Forebay
A spillway is a structure used in dam construction to provide the controlled release of water from a reservoir into the downstream area. Its primary purpose is to prevent the dam from being overtopped during floods or when the reservoir reaches its maximum capacity, which could otherwise lead to structural failure of the dam.
Why other options are incorrect:
- a. Power channel: This is the conduit that carries water from the intake/forebay to the surge tank or penstock to generate power.
- b. Penstock: This is a high-pressure pipe that delivers water from the reservoir or forebay directly to the turbines.
- d. Forebay: This is a holding basin located at the end of the headrace canal and the beginning of the penstock, used to regulate water flow and remove sediment before it enters the turbine.
An imaginary line joining the points of equal elevation on the surface of the earth represents:-
A)
Contour surface
B)
Contour line
C)
Level line
D)
Contour gradient
Step-by-step reasoning:
1. Definition: In surveying, a contour is defined as an imaginary line on the ground surface connecting all points that have the same elevation relative to a specific datum (usually mean sea level).
2. Analysis of Options:
- (a) Contour surface: This is not a standard surveying term; a surface is a 2D area, whereas the question asks for a 'line'.
- (b) Contour line: This matches the definition perfectly. It is the line joining points of equal elevation.
- (c) Level line: A level line is a line that is tangent to the curvature of the earth at every point and is perpendicular to the direction of gravity. While it represents a constant elevation, it is a physical/geometric concept of 'level', whereas the mapping of equal elevation points on a terrain surface is specifically called a contour line.
- (d) Contour gradient: This refers to the rate of change of elevation between two contour lines (the slope), not the line itself.
3. Conclusion: The correct technical term for an imaginary line joining points of equal elevation on the earth's surface is a Contour line.
In a Small Hydel Project, which part is responsible for generating electricity?
A)
Power House
B)
Reservoir
C)
Dam
D)
Penstock
In a Small Hydel Project (and hydroelectric projects in general), the components serve distinct functions:
1. Power House: This is the facility that houses the turbine and the generator. The turbine converts the kinetic/potential energy of flowing water into mechanical energy, and the generator converts that mechanical energy into electrical energy. Therefore, it is the part responsible for generating electricity.
2. Reservoir: This is the storage area for water, used to ensure a steady supply and to create the necessary head (height).
3. Dam: This is the structural barrier built across a river to create the reservoir and control water flow.
4. Penstock: This is the pressurized pipe or conduit that conveys water from the reservoir or intake structure down to the turbine in the power house.
Since the actual conversion of energy into electricity happens within the Power House, option (a) is the correct answer.
Which of the following is not a typical component of a Small Hydel Project?
A)
Intake structure
B)
Penstock
C)
Surge tank
D)
Nuclear reactor
A Small Hydel (Hydroelectric) Project generates electricity by harnessing the energy of flowing or falling water. The typical components include:
1. Intake structure: Used to divert water from the source (river/stream) into the system.
2. Penstock: A pressurized pipe that carries water from the reservoir or forebay to the turbine.
3. Surge tank: A storage reservoir used to absorb pressure increases (water hammer) when the turbine load changes suddenly.
In contrast, a Nuclear reactor is the core component of a Nuclear Power Plant, where nuclear fission is used to generate heat to produce steam. It has no functional role in a hydroelectric power system. Therefore, it is not a component of a Small Hydel Project.
The switching station which is the main link between the generating plant and the transmission system is called:-
A)
Switchyard
B)
Power House
C)
Turbine
D)
Generator
Step-by-step reasoning:
1. Analysis of the system: In a hydroelectric power project, electricity is generated in the Power House. However, the voltage produced by the generators is typically too low for efficient long-distance transmission.
2. Role of the Switchyard: The switchyard is the specialized area containing transformers (to step up voltage), circuit breakers, disconnect switches, and busbars. It acts as the critical interface or 'main link' that connects the generating units to the high-voltage transmission grid.
3. Evaluating other options:
- b. Power House: This is the building where the turbines and generators are located; it is the source, not the link to the transmission system.
- c. Turbine: This is a mechanical device that converts hydraulic energy into mechanical energy; it is not an electrical switching station.
- d. Generator: This is the machine that converts mechanical energy into electrical energy; while it produces the power, it requires the switchyard to safely integrate that power into the grid.
Therefore, the switchyard is the correct term for the switching station linking the plant to the transmission system.
The timber floor not spanning on the masonry wall but properly anchored to the wall gives:-
A)
Lateral restraint but not rotational restraint
B)
Rotational restraint but not lateral restraint
C)
Both lateral and rotational restraint
D)
Neither lateral nor rotational restraint
In structural engineering and building construction, the way a floor system is connected to a masonry wall determines the type of support provided.
1. **Lateral Restraint**: When a timber floor is 'properly anchored' to a wall (using anchors, bolts, or straps), it prevents the wall from buckling outwards and prevents the floor from sliding horizontally. This provides lateral stability to the structure.
2. **Rotational Restraint**: Rotational restraint (or moment restraint) occurs when the connection is rigid enough to prevent the beam or floor joist from rotating at the support. For a timber floor to provide rotational restraint, it would need a rigid, fixed-end connection (like a deep steel embedment or a reinforced concrete cast-in connection).
3. **Analysis of the scenario**: A timber floor anchored to a masonry wall typically acts as a 'pinned' or 'simply supported' connection in terms of rotation. While the anchors keep the floor from moving sideways (lateral restraint), they do not prevent the timber joists from rotating slightly as they deflect under load. Therefore, it provides lateral restraint but not rotational restraint.
After storage, the strength of cement:-
A)
Decreases
B)
Increases
C)
Remains same
D)
May increase or decrease
Cement is a hygroscopic material, meaning it readily absorbs moisture from the atmosphere. When cement is stored, it is exposed to atmospheric moisture and carbon dioxide. This leads to a process called 'pre-hydration,' where the cement particles react with moisture before they are actually mixed with water for construction. This partial hydration creates a layer of hydration products around the cement grains, which reduces the reactivity of the remaining unhydrated core. Consequently, the overall binding capacity and the compressive strength of the resulting concrete or mortar decrease as the storage period increases. For example, cement typically loses a significant percentage of its strength after 3 months of storage if not kept in moisture-proof conditions. Therefore, the strength of cement decreases after storage.
The net amount of power which is continuously available from a plant is:-
A)
Firm power
B)
Secondary power
C)
Installed capacity
D)
Primary power
In hydroelectric power plant terminology, power is categorized based on its reliability and availability throughout the year:
1. **Firm Power (Correct):** This is the amount of power that can be guaranteed to be available continuously during the most critical period (usually the driest season) of the year. It is the 'reliable' power that the plant can commit to the grid regardless of seasonal fluctuations in water flow.
2. **Secondary Power:** This is the power available in addition to the firm power. It depends on the availability of surplus water (e.g., during monsoon seasons) and cannot be guaranteed continuously throughout the year.
3. **Installed Capacity:** This refers to the maximum theoretical power output that the plant can produce if all turbines are running at full load. It is a measure of the plant's size, not its continuous availability.
4. **Primary Power:** While 'primary' often refers to the main source of energy, in the context of power availability and reliability in hydel projects, 'Firm Power' is the specific technical term used for continuous availability.