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Past Questions
Temporary hardness in water is caused by -
A)
Bicarbonates of Ca and Mg
B)
Sulphates of Ca and Mg
C)
Chlorides of Ca and Mg
D)
Nitrates of Ca and Mg
Hardness in water is defined as the concentration of multivalent metallic cations, primarily Calcium (Ca2+) and Magnesium (Mg2+). Hardness is classified into two types:
1. Temporary Hardness (Carbonate Hardness): This is caused by the presence of dissolved bicarbonate salts of calcium and magnesium [Ca(HCO3)2 and Mg(HCO3)2]. It is called 'temporary' because it can be easily removed by boiling the water, which decomposes the bicarbonates into insoluble carbonates (scale), water, and carbon dioxide.
2. Permanent Hardness (Non-carbonate Hardness): This is caused by the presence of sulphate, chloride, and nitrate salts of calcium and magnesium (e.g., CaSO4, MgCl2). These cannot be removed by boiling and require chemical treatment (like ion exchange or lime-soda process) for removal.
Therefore, options b, c, and d contribute to permanent hardness, while option a is the cause of temporary hardness.
Which one of the following is the factor to be considered during preparation of a Detailed Estimate?
A)
Quantity of materials
B)
Survey data
C)
Cost Analysis
D)
Rate Analysis
A Detailed Estimate is a comprehensive calculation of the total cost of a project, derived by multiplying the quantities of various items of work by their respective unit rates.
1. **Rate Analysis (Correct):** To prepare a detailed estimate, the engineer must determine the 'unit rate' for each item of work (e.g., concrete work per cubic meter). Rate analysis is the process of calculating this unit rate by considering the cost of materials, labor, equipment, overheads, and contractor's profit. Without rate analysis, a detailed estimate cannot be accurately priced.
2. **Quantity of materials (Incorrect):** While quantities are calculated, they are a result of the 'Quantity Take-off' process based on drawings. The 'factor' that determines the cost in a detailed estimate is the rate applied to those quantities.
3. **Survey data (Incorrect):** Survey data is a prerequisite for the design and planning phase (Preliminary/Rough Cost Estimate), but it is not the primary factor used during the actual calculation of a Detailed Estimate.
4. **Cost Analysis (Incorrect):** Cost analysis is a broader term that often refers to the overall financial feasibility or post-project evaluation, whereas 'Rate Analysis' is the specific technical tool used to build a detailed estimate.
Valve which allows water in one direction only is known as -
A)
Sluice valve
B)
Scour valve
C)
Air valve
D)
Reflux valve
A valve that allows water to flow in only one direction and prevents backflow (reverse flow) is known as a Reflux valve, also commonly called a Non-Return Valve (NRV) or Check Valve.
Here is the breakdown of the options:
1. Sluice Valve (a): Also known as a Gate Valve, it is used to completely stop or allow the flow of water. It is not designed to restrict direction, but rather to act as an on/off switch.
2. Scour Valve (b): These are placed at the lowest points of a pipeline to allow for the removal of accumulated sediment or to drain the pipe for maintenance.
3. Air Valve (c): These are used to release trapped air from the pipeline or to admit air to prevent vacuum formation (collapse) during drainage.
4. Reflux Valve (d): This valve is specifically designed to permit flow in one direction and automatically close if the flow reverses, making it the correct answer.
The weight of an item is measured correct to nearest -
A)
0.75 kg
B)
1 kg
C)
0.5 kg
D)
0.25 kg
In the field of Civil Engineering Estimation and Costing, specifically regarding the measurement of materials and items for billing and accounting purposes, standard conventions are followed to maintain uniformity. According to standard measurement practices (often aligned with IS 1200 or general public works department manuals), the weight of an item is typically measured and rounded to the nearest 0.5 kg. This provides a balance between precision and practical ease of measurement for bulk construction materials. Options a (0.75 kg), b (1 kg), and d (0.25 kg) are not the standard conventional rounding units used for general item weight measurement in standard estimation practices.
The gradient on a road is 1 in 20, the camber on the road is -
A)
1 in 10
B)
1 in 20
C)
1 in 30
D)
1 in 40
In highway engineering, the camber (cross-slope) is provided to drain rainwater from the road surface to the shoulders. According to standard IRC (Indian Roads Congress) guidelines and general pavement design principles, the camber should be sufficient to ensure drainage but not so steep as to compromise the stability of the vehicle. A general rule of thumb used in many technical examinations for this specific relationship is that the camber should be approximately 1/2 to 1/4 of the longitudinal gradient to ensure effective drainage without causing excessive lateral instability. Specifically, for a gradient of 1 in 20 (5%), a camber of 2.5% (1 in 40) is a standard design value for bituminous or concrete roads to ensure that the resultant slope allows water to flow off the pavement efficiently. While camber depends more on the surface material (e.g., 2-3% for bituminous, 3-4% for gravel), in the context of this specific multiple-choice question, 1 in 40 is the most technically sound choice among the options provided to maintain a safe and functional road geometry.
Depreciation is calculated under diminishing balance method, based on -
A)
Original value
B)
Book value
C)
Scrap value
D)
None of these
In valuation and accounting, there are two primary methods for calculating depreciation:
1. **Straight Line Method (SLM):** Depreciation is calculated as a fixed percentage of the 'Original Value' (or Cost) of the asset every year. The amount of depreciation remains constant throughout the life of the asset.
2. **Diminishing Balance Method (DBM):** Also known as the Reducing Balance Method or Written Down Value (WDV) method. In this method, depreciation is applied as a fixed percentage to the 'Book Value' (the remaining value of the asset after previous years' depreciation has been deducted) at the beginning of each year. Consequently, the depreciation amount decreases every year as the book value declines.
Therefore, since the question specifically asks about the Diminishing Balance Method, the calculation is based on the Book Value.
Find the next number in the series: 21, 34, 55, 89, ?
A)
144
B)
123
C)
102
D)
101
The given series is 21, 34, 55, 89, ?. By analyzing the relationship between the numbers, we can see that each term is the sum of the two preceding terms. This is a characteristic of the Fibonacci sequence (or a Fibonacci-style additive series).
Step-by-step calculation:
1. 21 + 34 = 55
2. 34 + 55 = 89
3. 55 + 89 = 144
Therefore, the next number in the series is 144.
Comparing this result to the options:
- Option (a) 144 matches our calculation.
- Options (b) 123, (c) 102, and (d) 101 do not follow the additive pattern of the series.
The multiplying constant of tacheometer is generally about -
A)
200
B)
100
C)
50
D)
1
In tacheometry, the horizontal distance (D) between the instrument station and the staff station is calculated using the formula: D = ks + c, where 'k' is the multiplying constant and 'c' is the additive constant.
1. The multiplying constant (k) is defined as the ratio of the focal length (f) of the objective lens to the staff intercept factor (i), i.e., k = f/i.
2. In most modern tacheometers, the instrument is designed as an 'anallactic lens' system. This means the lens is specifically designed so that the additive constant (c) becomes zero, and the multiplying constant (k) is exactly 100.
3. This standardization (k = 100) simplifies field calculations significantly, as the distance becomes exactly 100 times the staff intercept.
Comparing the options:
- Option (a) 200: Incorrect; not a standard design value.
- Option (b) 100: Correct; the standard value for almost all commercial tacheometers.
- Option (c) 50: Incorrect; not a standard design value.
- Option (d) 1: Incorrect; this would imply the distance is equal to the staff intercept, which is physically impossible for the optics used.
The basis for arriving at a correct rate per unit work or supply of work specifications such as labour, materials, and equipment is -
A)
Cubic rate estimate
B)
Tender
C)
Analysis of rates
D)
Schedule of Rates
The process of determining the cost of a particular unit of work by calculating the quantities and costs of materials, labor, equipment, and overheads required to complete that unit is known as the 'Analysis of Rates'. It is the fundamental basis used to derive the unit rates found in a Schedule of Rates (SOR).
Why other options are incorrect:
- a. Cubic rate estimate: This is a preliminary or approximate method of estimating the total cost of a building based on its volume; it does not determine the unit rate of specific work items.
- b. Tender: A tender is a formal offer or bid submitted by a contractor to execute a project at a specified price; it is a result of the estimation process, not the basis for calculating unit rates.
- d. Schedule of Rates (SOR): While the SOR contains the rates per unit, it is a compiled document (a list). The 'basis' or the 'process' used to arrive at those rates is the Analysis of Rates.
The camber required for a pavement depends on -
A)
Speed of vehicle
B)
Type of pavement
C)
Load and tyre pressure
D)
Road lane
Camber (also known as cross-slope) is provided to the surface of the road to drain off rainwater from the pavement surface to the side drains. The amount of camber required depends primarily on two factors: 1) The type of pavement surface (e.g., concrete, bituminous, or water-bound macadam) and 2) The amount of rainfall in the area.
- Type of pavement: Smooth surfaces like concrete or asphalt (bituminous) have less friction and allow water to flow easily, thus requiring a lower camber (typically 1.7% to 2.5%). Rougher surfaces like WBM or gravel require a steeper camber (typically 2.5% to 4%) to ensure effective drainage despite the surface irregularities.
Why other options are incorrect:
- Speed of vehicle (a): This affects the design of super-elevation (banking) on curves, not the camber of a straight road.
- Load and tyre pressure (c): These factors influence the thickness and structural design of the pavement layers, not the surface slope for drainage.
- Road lane (d): The number of lanes affects the total width of the carriage way, but the slope (camber) of each individual lane is determined by the material and climate.
The value assigned to a property, such as a home, by the local government is called -
A)
Property value
B)
Sinking value
C)
Assessed value
D)
Property valuation
Step-by-step reasoning:
1. **Definition of Assessed Value**: In the context of valuation and taxation, the 'Assessed Value' is the value assigned to a property by a local government authority (such as a municipal corporation or tax assessor). This value is used specifically as the basis for calculating property taxes.
2. **Analysis of Option (a) Property Value**: This is a general term that can refer to the market value, replacement cost, or any other valuation. It is not specifically the value assigned by the government for taxation.
3. **Analysis of Option (b) Sinking Value**: This is an incorrect term in this context. A 'Sinking Fund' is a fund created to replace a building or pay off a debt at the end of its useful life, but 'Sinking Value' is not a standard term for government property assessment.
4. **Analysis of Option (d) Property Valuation**: This refers to the *process* of estimating the value of a property, rather than the *result* or the specific value assigned by a government body.
Therefore, the specific term for the value assigned by the local government for tax purposes is the Assessed Value.
The coliform organism in 100 ml of drinking water should not be more than -
A)
1000
B)
450
C)
100
D)
1
In Environmental Engineering and Public Health standards, coliform bacteria are used as 'indicator organisms' to detect fecal contamination in water. According to the World Health Organization (WHO) and the Bureau of Indian Standards (BIS 10500), for water to be considered safe for drinking (potable), the coliform count must be zero. However, in many regulatory contexts and competitive exam standards for 'treated drinking water,' the permissible limit is often cited as 'not more than 1' or '0' per 100 ml. If the coliform count exceeds this, the water is considered contaminated and requires further disinfection. Options a, b, and c (1000, 450, 100) are far too high for drinking water and would indicate severe contamination, making them incorrect.
If 'P' is the standard consistency of cement, the amount of water used in conducting the initial setting time test on cement is -
A)
0.65P
B)
0.85P
C)
0.6P
D)
0.8P
In the testing of cement, 'P' represents the Standard Consistency (the percentage of water required to allow a Vicat plunger to penetrate to a depth of 5-7 mm from the bottom of the mold).
According to IS 4031 (Part 5), the test for the Initial and Final Setting Time of cement is conducted using a cement paste prepared with a specific amount of water relative to the standard consistency:
1. The amount of water used for the setting time test is 0.85 times the percentage of water required to produce standard consistency (0.85P).
2. This reduction in water content (from 1.0P to 0.85P) is done to ensure that the paste has a consistency that allows the Vicat needle to penetrate but is stiff enough to provide a measurable resistance as the cement begins to set.
Therefore, if P is the standard consistency, the water used for the setting time test is 0.85P.
The accurate method for calculating average rainfall of a catchment area is -
A)
Arithmetic mean
B)
Theissen polygon
C)
Isohyetal
D)
Both (a) & (b)
In hydrology, there are three primary methods used to calculate the average precipitation (rainfall) over a catchment area:
1. **Arithmetic Mean Method**: This is the simplest method where the rainfall at various stations is summed and divided by the number of stations. It is only accurate if the stations are uniformly distributed and the terrain is flat (no significant topographic variation).
2. **Thiessen Polygon Method**: This method assigns a weight to each rain gauge based on the area it represents. It is more accurate than the arithmetic mean because it accounts for non-uniform distribution of gauges, but it does not account for changes in rainfall due to topography (elevation).
3. **Isohyetal Method**: This method involves drawing lines of equal rainfall (isohyets) on a map. It is considered the most accurate method because it accounts for both the non-uniform distribution of rain gauges and the topographic effects (orographic rainfall) of the terrain.
Since the question asks for the 'accurate method' (implying the most accurate among the choices), the Isohyetal method is the correct answer.
A wedge failure of soil mass will slide along an inclined plane.
A)
Wedge failure
B)
Rotational failure
C)
Translation failure
D)
Combined failure
In soil mechanics and slope stability analysis, failures are categorized based on the geometry of the slip surface:
1. **Wedge Failure (Option a):** This occurs when a block of soil or rock slides along a planar surface (an inclined plane). It typically happens in slopes where there is a distinct plane of weakness, such as a bedding plane or a joint, dipping out of the slope face.
2. **Rotational Failure (Option b):** This is characterized by a curved or circular slip surface. It is the most common type of failure in homogeneous, cohesive soils (like clays).
3. **Translational Failure (Option c):** This occurs when the soil mass moves downward along a relatively flat or planar surface, but unlike wedge failure, it usually involves a larger mass moving along a weak layer (like a thin layer of soft clay) beneath a stronger layer.
4. **Combined Failure (Option d):** This is a complex failure mode that involves a combination of rotational and translational movements.
Since the question specifically mentions sliding along an 'inclined plane', it describes the fundamental mechanism of a wedge failure.
A clay sample has a void ratio of 0.50 in the dry condition. The grain specific gravity has been Determined as 2.70. What is the shrinkage limit of this clay?
A)
18.51%
B)
17.5%
C)
19.51%
D)
16.51%
To find the shrinkage limit (SL) of the clay, we use the relationship between the void ratio at the shrinkage limit and the specific gravity of the soil solids.
1. **Understanding the Shrinkage Limit**: The shrinkage limit is the water content at which the soil remains at a constant volume even if the water content is further reduced. At this point, the soil is fully saturated, and the void ratio is equal to the void ratio in the dry condition (since no further volume change occurs).
2. **Given Data**:
- Void ratio in dry condition ($e_{dry}$) = 0.50
- Specific gravity of solids ($G$) = 2.70
3. **Formula**: For a saturated soil at the shrinkage limit, the water content ($w_{SL}$) is given by:
$w_{SL} = \frac{e_{SL}}{G} \times 100$
Since the volume remains constant from the shrinkage limit to the dry state, the void ratio at the shrinkage limit ($e_{SL}$) is equal to the void ratio in the dry condition ($e_{dry}$).
$e_{SL} = 0.50$
4. **Calculation**:
$w_{SL} = \frac{0.50}{2.70} \times 100$
$w_{SL} = 0.185185... \times 100$
$w_{SL} = 18.5185...\%$
Rounding to two decimal places, we get 18.51%.
Therefore, option (a) is the correct answer. Options (b), (c), and (d) are incorrect as they do not match the calculated value based on the provided soil properties.
In stability analysis, the term mobilised shear strength is referred to as -
A)
Shear strength
B)
Maximum shear strength
C)
Applied shear stress
D)
None of these
In soil mechanics and stability analysis (such as slope stability), it is crucial to distinguish between the 'available' shear strength and the 'mobilised' shear strength.
1. **Available Shear Strength**: This is the maximum resistance the soil can offer against sliding, typically defined by the Mohr-Coulomb failure criterion: τ = c + σ tan(φ). This represents the strength at the point of failure.
2. **Mobilised Shear Strength**: This refers to the actual shear stress that is currently being exerted on the soil mass due to external loads or gravity to maintain equilibrium. In other words, it is the 'applied shear stress' required to keep the slope or structure stable at a given factor of safety.
3. **Relationship**: If the mobilised shear strength equals the available shear strength, the factor of safety is 1.0 (the soil is at the point of failure). If the mobilised shear strength is less than the available strength, the system is stable.
Therefore, 'mobilised shear strength' is synonymous with the 'applied shear stress' acting on the failure plane.
Seasoning of timber is required to -
A)
Soften the timber
B)
Harden the timber
C)
Straighten the timber
D)
Remove sap from the timber
Seasoning of timber is the process of reducing the moisture content (sap) of the wood to a level that is in equilibrium with the environment in which the timber will be used. Freshly felled trees contain a large amount of water (sap) in the cell walls and cavities. If this moisture is not removed, the timber is prone to shrinkage, warping, cracking, and decay by fungi or insects. By removing the sap through natural (air) or artificial (kiln) seasoning, the timber becomes more stable, durable, and stronger.
Analysis of other options:
- Option (a) Soften the timber: Seasoning actually makes the timber more rigid and stable, not softer.
- Option (b) Harden the timber: While seasoning increases strength and stability, the primary technical purpose is moisture removal, not 'hardening' in a chemical or physical sense like tempering steel.
- Option (c) Straighten the timber: Seasoning cannot straighten a naturally curved or warped piece of wood; in fact, improper seasoning can cause further warping.
The concept of unit hydrograph was first introduced by -
A)
Dalton
B)
Sherman
C)
Horton
D)
Thiessen
The Unit Hydrograph (UH) theory was first introduced by L.K. Sherman in 1932. A unit hydrograph is defined as the direct runoff hydrograph resulting from one unit (e.g., 1 cm or 1 inch) of effective rainfall occurring uniformly over a watershed for a specified duration.
Analysis of other options:
- a. Dalton: Known for Dalton's Law of partial pressures and contributions to meteorology/evaporation.
- c. Horton: Known for the Horton infiltration model, which describes the rate of infiltration of water into the soil.
- d. Thiessen: Known for the Thiessen polygon method used to calculate the average precipitation over a catchment area.
The soil within a soil mass bounded by an isobar of given vertical pressure intensity is called :
A)
Isotropic
B)
Contact pressure
C)
Pressure bulb
D)
Pressure intensity
In soil mechanics, when a load is applied to the surface of a soil mass, the vertical stress increases with depth and spreads laterally. An 'isobar' is a line (or surface in 3D) connecting points of equal vertical pressure intensity. The volume of soil contained within a specific isobar (usually the 10% or 20% of the surface contact pressure) is referred to as the 'Pressure Bulb' or 'Stress Bulb'. This concept is critical for determining the depth of influence of a foundation and assessing potential settlement of adjacent structures.
Why other options are incorrect:
- a. Isotropic: This refers to a material property where physical properties are the same in all directions; it does not describe a volume of soil bounded by pressure.
- b. Contact pressure: This is the pressure exerted at the interface between the foundation base and the soil surface, not the volume of soil below it.
- d. Pressure intensity: This is a scalar value representing the magnitude of pressure at a specific point, not the soil mass bounded by an isobar.
Which of the following will have a finite slope -
A)
Embankment
B)
Earth Dam
C)
Canals
D)
All of these
In soil mechanics and geotechnical engineering, a 'finite slope' refers to a slope that has a definite height and a specific horizontal extent (it is not an infinite slope that extends indefinitely with a constant dip).
1. Embankments: These are artificial slopes created by piling soil to raise the ground level for roads or railways. They have a specific height and a defined slope angle to ensure stability against sliding. Thus, they are finite slopes.
2. Earth Dams: These are massive structures made of compacted soil. They have distinct upstream and downstream slopes with specific heights and widths to resist water pressure and prevent failure. Thus, they are finite slopes.
3. Canals: The side slopes of canal banks (embankments) are designed with a specific gradient to prevent the soil from collapsing into the channel. These slopes have a finite vertical height from the bed to the top of the bank. Thus, they are finite slopes.
Since all three structures involve slopes with defined boundaries and heights, they all fall under the category of finite slopes.
A ____ is a passive structure, which protects against erosion caused by wave action, storm surge and currents.
A)
Revetment walls
B)
Breast walls
C)
Crib walls
D)
Toe walls
A revetment is a protective facing, usually made of stone, concrete blocks, or geotextiles, placed on an embankment or shoreline. Its primary purpose is to act as a passive structure that absorbs the energy of incoming water to protect the underlying soil from erosion caused by wave action, storm surges, and currents.
Why other options are incorrect:
- Breast walls: These are typically used to retain soil or prevent the sliding of a slope, often used in road construction or along river banks to prevent lateral movement, but they are not specifically designed as passive wave-energy absorbers.
- Crib walls: These are interlocking timber or concrete frames filled with crushed stone or soil, used primarily as retaining walls for steep slopes.
- Toe walls: These are small walls constructed at the base (toe) of a larger retaining wall or slope to prevent scouring and provide stability to the main structure, rather than protecting a wide area against storm surges and wave action.
The transition from debris slide to debris flow depends on the
A)
Water content
B)
Size of rock
C)
Depth of soil
D)
Hardness of rock
In geotechnical engineering and geomorphology, a debris slide is a mass movement where the material moves as a relatively coherent block or along a distinct failure plane. A debris flow, however, is a fluid-like movement of saturated soil and rock debris. The critical factor that triggers the transition from a slide (solid-like behavior) to a flow (fluid-like behavior) is the increase in water content. High water content increases the pore water pressure, which reduces the effective stress and the shear strength of the material, effectively 'lubricating' the mass and allowing it to behave as a viscous fluid. While rock size and hardness influence the composition of the debris, they do not dictate the physical transition from sliding to flowing; the saturation level (water content) is the primary driver of this phase change in mass wasting processes.
Quantity of water extracted by gravity-drainage from a saturated water bearing stratum is called -
A)
Groundwater yield
B)
Permeability
C)
Groundwater velocity
D)
Groundwater flow
Step-by-step reasoning:
1. **Definition of Groundwater Yield**: In hydrology, the 'yield' of an aquifer refers to the amount of water that can be extracted from a saturated water-bearing stratum (aquifer) under the influence of gravity. It is the volume of water that can be drained by gravity alone.
2. **Analysis of Option (b) Permeability**: Permeability is a property of the soil or rock that describes the ease with which a fluid can flow through it. It is a coefficient (k), not a quantity of water extracted.
3. **Analysis of Option (c) Groundwater velocity**: Velocity refers to the speed at which water moves through the pores of the aquifer (often calculated using Darcy's Law). It is a rate of movement (length/time), not a quantity of water.
4. **Analysis of Option (d) Groundwater flow**: This is a general term describing the movement of water through an aquifer from an area of higher hydraulic head to an area of lower hydraulic head. While yield is a result of flow, 'flow' itself is the process, whereas 'yield' is the specific quantity extracted.
Therefore, the quantity of water extracted by gravity-drainage is specifically termed as the groundwater yield.
What treatment is adopted for making timber fire - resistant?
A)
ASCU treatment
B)
Abel’s process
C)
Creosoting
D)
Tarring
The correct answer is ASCU treatment. Here is the detailed breakdown:
1. **ASCU Treatment**: This is a chemical process used to make timber fire-resistant. ASCU stands for Ammonium phosphates, Sulphate of alumina, Chloride of zinc, and Urea. The timber is impregnated with these chemicals, which act as flame retardants by reducing the combustibility of the wood.
2. **Abel's Process**: This is a method used for the preservation of timber against decay and insect attacks (specifically using zinc chloride), but it is not primarily a fire-resistance treatment.
3. **Creosoting**: This is a preservative treatment where timber is impregnated with creosote (a distilled oil from coal tar). It is used to protect timber from fungi, insects, and moisture, particularly for poles and sleepers, but it does not make timber fire-resistant (in fact, creosote is flammable).
4. **Tarring**: This involves applying a layer of tar to the surface of the timber to make it waterproof and protect it from moisture and decay. It is not a fire-resistance treatment.