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Past Questions — 2025
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.
The term “Gross Head” in a Small Hydel Project refers to:-
A)
The difference in water level between the forebay and the tailrace
B)
The pressure of water at the turbine inlet
C)
The height of the dam
D)
The total capacity of the reservoir
In hydroelectric power terminology, 'Head' refers to the vertical distance water falls to drive a turbine.
1. **Gross Head**: This is the total vertical distance between the water surface at the intake (or forebay) and the water surface at the discharge point (tailrace). It represents the maximum potential energy available per unit weight of water.
2. **Net Head**: This is the actual head available at the turbine inlet after subtracting losses due to friction in the penstock, bends, and valves from the Gross Head (Net Head = Gross Head - Head Losses).
Evaluating the options:
- **Option a** is correct as it defines the total vertical drop from the source (forebay) to the exit (tailrace).
- **Option b** describes the 'Net Head' or the actual pressure head at the turbine.
- **Option c** is incorrect because the height of the dam is a structural dimension and does not necessarily equal the hydraulic head (which depends on water levels).
- **Option d** refers to the volume of water storage, not the hydraulic head.
Main ingredient in the cement composition is:-
A)
Silica
B)
Lime
C)
Clay
D)
Alumina
Portland cement is manufactured by burning a mixture of calcareous (lime-bearing) and argillaceous (clay-bearing) materials. The chemical composition of cement consists of several oxides, with Lime (CaO) being the primary constituent.
1. Lime (CaO): This is the main ingredient, typically making up about 60% to 67% of the cement. It provides strength and soundness.
2. Silica (SiO2): The second most abundant ingredient (approx. 17% to 25%), which contributes to the strength of the cement over time.
3. Alumina (Al2O3): Present in smaller quantities (approx. 3% to 8%), it acts as a flux to lower the clinkering temperature.
4. Iron Oxide (Fe2O3): Present in small amounts (approx. 0.5% to 6%), giving cement its characteristic grey color.
Since Lime has the highest percentage by weight in the composition of cement, it is the main ingredient.
First class timber has an average life of:-
A)
More than 10 years
B)
5 to 10 years
C)
Less than one year
D)
1 to 5 years
In the classification of timber based on durability (resistance to decay and insect attack), timber is generally categorized into classes. First-class timber is characterized by high durability, meaning it is highly resistant to decay and can withstand environmental exposure for a prolonged period. According to standard engineering and forestry classifications for building materials, first-class timber is expected to have a service life of more than 10 years (often extending to several decades depending on the species and treatment). Options b, c, and d represent durations typical of lower-grade, non-durable, or perishable timbers that are susceptible to rapid decay.
The maximum power which can be developed by generators at normal head with full flow is:-
A)
Load factor
B)
Installed capacity
C)
Peak load
D)
Average load
In hydroelectric power plants, the 'Installed Capacity' refers to the maximum theoretical power that the generators can produce when operating under design conditions—specifically, at the normal operating head (the vertical distance the water falls) and with the full design flow rate of water passing through the turbines.
Here is why the other options are incorrect:
- a. Load factor: This is the ratio of the average load over a given period to the peak load during that period. It is a dimensionless ratio, not a measure of power capacity.
- c. Peak load: This is the maximum electrical demand placed on the system by consumers at a specific point in time. While it may coincide with installed capacity, it is a demand metric, not a generator capability metric.
- d. Average load: This is the mean power demand over a specific period, which is always less than or equal to the peak load and installed capacity.
The standard thickness of ceiling plaster is:-
A)
6 mm
B)
10 mm
C)
12 mm
D)
15 mm
In building construction and plastering standards (as per IS codes and general engineering practice), the thickness of plaster varies depending on the surface being treated. For ceilings, the standard thickness of plaster is typically 12 mm. This thickness is chosen to provide a smooth, level finish to the concrete slab or beams while ensuring the plaster has sufficient bond strength to resist peeling or sagging due to gravity.
Comparison with other options:
- 6 mm: This is generally too thin for a standard ceiling coat and is more common for thin skim coats or specific internal finishes.
- 10 mm: While used in some specific regional practices, it is not the standard engineering benchmark for ceiling plaster.
- 15 mm: This thickness is more common for internal wall plastering (usually 12-15 mm) or external plastering (which can be 18-20 mm), but is considered excessive for ceilings as it increases the dead load and the risk of debonding.
The amount of electrical energy that can be generated at Small Hydel Project depends upon:-
A)
Head of water
B)
Quantity of water
C)
Efficiency of Alternator
D)
Diameter of Penstock
To determine the electrical energy generated by a Small Hydel Project, we look at the fundamental power equation for hydroelectricity: P = η × ρ × g × Q × H.
1. P = Power (Watts)
2. η = Overall efficiency (including turbine and alternator)
3. ρ = Density of water
4. g = Acceleration due to gravity
5. Q = Discharge or Quantity of water (m³/s)
6. H = Net Head (m)
Electrical Energy (E) is the integral of Power over time (E = P × t). Therefore, the energy generated depends on the Head (H), the Quantity of water (Q), and the Efficiency (η).
However, in the context of competitive exams for Small Hydel Projects (SHP), the 'Quantity of water' (discharge) is often the most critical limiting factor and the primary variable that determines the total energy potential over a given period (annual energy generation), as the head is usually a fixed geographical constant for a specific site.
While options (a), (b), and (c) all mathematically influence the power, the question asks what the energy 'depends upon'. In many standard engineering textbooks for SHP, the availability of the 'Quantity of water' (flow rate) is the primary determinant of the project's capacity and energy output.
Note: If this were a 'select all that apply' question, a, b, and c would be correct. In a single-choice format, 'Quantity of water' is the most fundamental resource requirement for energy generation.
The opened or closed conduits that carry water to the turbines is:-
A)
Power channel
B)
Penstock
C)
Desilting Tank
D)
Forebay
In a hydroelectric power plant, the penstock is the pressurized pipe or conduit that conveys water from the forebay or reservoir directly to the turbine. It is designed to handle high pressure and is typically closed (piped) to maintain the head of water.
Analysis of other options:
- a. Power channel: This is a general term, but the specific conduit leading to the turbine is the penstock.
- c. Desilting Tank: This is a basin used to remove silt and sediment from the water before it enters the conveyance system to prevent erosion of the turbine blades.
- d. Forebay: This is a holding basin or reservoir located at the end of the headrace canal, acting as a transition point before the water enters the penstock.
The bond strength of concrete increases with:-
A)
The quality of steel
B)
The tensile strength of the steel
C)
The grade of concrete
D)
The quality of sand
Bond strength in reinforced concrete refers to the capacity of the concrete to grip the reinforcing steel bar, preventing slippage. This bond is primarily achieved through chemical adhesion, friction, and mechanical interlocking (in the case of deformed bars).
1. Why 'The grade of concrete' is correct: The grade of concrete is a measure of its compressive strength. As the grade of concrete increases (e.g., from M20 to M40), the density and the strength of the cement paste matrix increase. This results in a stronger grip (higher adhesion and higher bearing pressure on the ribs of deformed bars) around the steel reinforcement, thereby increasing the overall bond strength.
2. Why other options are incorrect:
- (a) The quality of steel: While the surface condition (like ribs) matters, 'quality' is a general term. High-quality steel doesn't inherently increase the bond unless it refers specifically to the deformation pattern.
- (b) The tensile strength of the steel: Tensile strength is an internal property of the steel (its ability to resist pulling forces). It does not affect how the concrete grips the outside of the bar.
- (d) The quality of sand: While the grading of sand affects the workability and density of concrete, it is the overall grade (strength) of the hardened concrete that is the primary driver of bond strength.
The primary function of a trash rack in a Small Hydel Project is to:-
A)
Regulate water flow
B)
Prevent debris from entering the turbine
C)
Increase water pressure
D)
Generate electricity
A trash rack is a screen made of metal bars installed at the intake of a hydroelectric project (including Small Hydel Projects). Its primary purpose is to act as a filter that prevents floating debris—such as logs, leaves, plastic, and other foreign objects—from entering the penstock and reaching the turbine. If debris enters the turbine, it can cause severe mechanical damage to the runner blades, clog the system, or cause imbalances that lead to turbine failure.
Analysis of other options:
- Option (a) Regulate water flow: This is the function of the intake gate or the governor valve, not the trash rack.
- Option (c) Increase water pressure: Water pressure is increased by the head (height difference) and the design of the penstock; a trash rack actually causes a slight pressure drop (head loss) due to friction.
- Option (d) Generate electricity: Electricity is generated by the turbine and the generator set, not by the intake screening system.
A key consideration when selecting a site for a Small Hydel Project is:-
A)
Distance from major cities
B)
Availability of suitable land for construction of weir
C)
Proximity to existing transmission lines
D)
Availability of skilled labor
In the selection of a site for a Small Hydel Project (SHP), the primary technical requirement is the ability to divert or store water efficiently to create the necessary head and flow. The construction of a weir (or diversion dam) is fundamental to this process as it ensures a steady supply of water into the intake structure. Therefore, the availability of suitable land—specifically land with stable geological foundations and appropriate topography to support a weir—is a critical technical consideration.
Why other options are incorrect:
- Option (a) Distance from major cities: While urban proximity affects demand, it is not a primary technical site selection criterion for the project's viability.
- Option (c) Proximity to existing transmission lines: This is an economic consideration to reduce costs, but it is secondary to the physical possibility of harnessing water (the weir).
- Option (d) Availability of skilled labor: Labor can be transported to a site; it does not dictate whether a specific geographical location is suitable for a hydroelectric project.
In geodetic surveys, higher accuracy is achieved, if:-
A)
Curvature of the earth surface is ignored
B)
Curvature of the earth surface is taken into account
C)
Angles between the curved lines are treated as plane angles
D)
Satellite signal is taken into account
Surveying is broadly divided into two categories: Plane Surveying and Geodetic Surveying.
1. Plane Surveying: In this type of survey, the earth's surface is assumed to be a flat plane. The curvature of the earth is ignored. This is acceptable for small areas (typically less than 250 sq km) because the error introduced is negligible.
2. Geodetic Surveying: This is used for very large areas or high-precision work. Because the earth is an oblate spheroid, the curvature of the surface becomes significant over long distances. To achieve higher accuracy, the curvature of the earth must be taken into account using spherical trigonometry and ellipsoidal calculations.
Analysis of options:
- Option (a) is incorrect because ignoring curvature leads to 'plane surveying', which is less accurate for large areas.
- Option (b) is correct because accounting for the earth's curvature is the defining characteristic of geodetic surveying to ensure high precision.
- Option (c) is incorrect because treating curved lines as plane angles is a simplification used in plane surveying, not geodetic surveying.
- Option (d) is incorrect because while satellites (GPS/GNSS) are tools used in modern geodetic surveys, the fundamental principle that enables the 'higher accuracy' of the geodetic method itself is the mathematical consideration of the earth's curvature.
A first class brick when immersed in cold water for 24 hours should not absorb water more than:-
A)
15%
B)
20%
C)
22%
D)
25%
According to the Indian Standard (IS) specifications for bricks, the water absorption test is used to determine the quality and porosity of the brick. For a first-class brick, the maximum permissible water absorption after being immersed in cold water for 24 hours is 20% of its dry weight.
Breakdown of standards:
- First Class Bricks: Water absorption should not exceed 20% of dry weight.
- Second Class Bricks: Water absorption should not exceed 22% of dry weight.
- Third Class Bricks: Water absorption may be higher, typically around 25% or more depending on the specific local standard.
Therefore, option (b) is the correct technical requirement for a first-class brick.
The difference in height of the water level between the level in storage and tailrace is called:-
A)
Net head
B)
Gross head
C)
Rated head
D)
Design head
In hydroelectric power plants, the 'head' refers to the vertical distance the water falls to drive the turbine.
1. **Gross Head (Option b):** This is the total vertical difference in elevation between the water surface at the intake (storage reservoir) and the water surface at the tailrace (the point where water exits the plant). It represents the maximum potential energy available per unit weight of water.
2. **Net Head (Option a):** This is the actual head available at the turbine inlet. It is calculated as the Gross Head minus the losses due to friction in the penstock, bends, and valves (Net Head = Gross Head - Head Losses).
3. **Rated Head (Option c):** This is the head at which the turbine is designed to operate to produce its rated output power.
4. **Design Head (Option d):** This is the specific head for which the turbine is optimized for maximum efficiency during the design phase.
Since the question specifically asks for the difference in height between the storage level and the tailrace level, it is referring to the total potential difference, which is the Gross Head.
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.
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.
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.
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.
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.
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 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.
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.