← MES Jr. Grade
Past Questions
Which of the following is not a direct method of distance measurement?
A)
Pacing
B)
Tacheometry
C)
Odometer
D)
EDM (Electronic Distance Measurement)
Distance measurement in surveying is broadly classified into Direct and Indirect methods.
1. Direct Methods: These involve physically measuring the distance along the line or using a device that tracks the actual path traveled.
- Pacing (Option a): A direct method where distance is estimated by counting steps.
- Odometer/Measuring Wheel (Option c): A direct method where a wheel is rolled along the ground to measure distance.
- EDM (Option d): While it uses electromagnetic waves, it is categorized as a direct measurement of the line distance between two points (though some textbooks distinguish between 'mechanical' and 'electronic' direct methods, in the context of this specific multiple-choice set, EDM is a direct measurement of the distance).
2. Indirect Methods: These involve calculating the distance using trigonometric relationships or optical properties without physically traversing the entire length.
- Tacheometry (Option b): This is an indirect method. It uses a transit telescope with stadia hairs to measure the distance based on the intercept of the staff, applying the formula D = ks + c. Since the distance is derived from an angular measurement and a staff intercept rather than a direct physical measurement of the line, it is an indirect method.
Therefore, Tacheometry is the correct answer as it is not a direct method.
Using remote sensing, if the spatial resolution of an image is 1 m and the image covers an area of 10 km2, what is the total number of pixels?
A)
10000
B)
100000
C)
1000000
D)
10000000
Option D is correct: 10000000.
What is the significance of flood routing in reservoir management?
A)
To estimate the sediment load in the reservoir
B)
To determine the optimal location for a new dam
C)
To predict the inflow and outflow hydrographs
D)
To calculate the evaporation rates from the reservoir
Flood routing is the process of determining the change in the magnitude and timing of a flood wave as it moves downstream or passes through a reservoir. In reservoir management, 'Reservoir Routing' specifically refers to the process of calculating the outflow hydrograph based on a known inflow hydrograph and the storage-discharge relationship of the reservoir. The primary goal is to attenuate the peak of the flood (reducing the peak outflow) and delay the timing of the peak to protect downstream areas and manage reservoir levels safely.
Why other options are incorrect:
- Option (a): Sediment load estimation is part of sediment transport analysis and reservoir sedimentation studies, not flood routing.
- Option (b): Determining the optimal location for a dam involves geotechnical, topographical, and environmental site selection studies.
- Option (d): Evaporation rates are calculated using pan evaporation data or water balance equations, which is a separate component of reservoir water budget analysis.
Based on Weibull’s formula, what is the mathematical expression for return period?
A)
T=(N+1)/m
B)
T=N+1
C)
T=m/N
D)
T=m/(N+1)
In hydrology, the return period (T) of a specific event (like a flood or rainfall) is estimated using the plotting position formula. Weibull's formula is one of the most widely used methods for this purpose.
1. **Definition of Terms**:
- **T**: The return period (the average interval of time between occurrences of an event of a certain magnitude).
- **m**: The rank of the event when the data is sorted in descending order (m=1 for the largest event, m=2 for the second largest, and so on).
- **N**: The total number of years of record or the total number of observations.
2. **The Formula**: Weibull's formula states that the return period is given by T = (N + 1) / m. This formula is preferred over the simpler T = N/m because it provides a better unbiased estimate, especially for the largest event (m=1), where T = N+1 rather than T = N.
3. **Analysis of Options**:
- **Option a (T=(N+1)/m)**: This is the correct mathematical expression for Weibull's plotting position.
- **Option b (T=N+1)**: This is only true for the single largest event (where m=1), not a general expression for any rank m.
- **Option c (T=m/N)**: This represents the probability of exceedance (approximately), not the return period.
- **Option d (T=m/(N+1))**: This is the formula for the probability of exceedance (P = 1/T), not the return period itself.
In hydrology, “antecedent moisture condition” (AMC) refers to:
A)
Soil moisture content after a rainfall event
B)
Soil moisture content before a rainfall event
C)
Average soil moisture content over a month
D)
Maximum soil moisture content
In hydrology, the Antecedent Moisture Condition (AMC) refers to the degree of wetness of a catchment area or soil profile immediately prior to a specific rainfall event. It is a critical parameter because it determines the infiltration capacity of the soil: if the soil is already saturated (high AMC), more of the rainfall will become surface runoff; if the soil is dry (low AMC), more water will infiltrate into the ground. The SCS Curve Number method commonly uses AMC levels (AMC I, II, and III) to adjust the runoff curve number based on the moisture state of the basin before the storm occurs.
- Option (a) is incorrect because moisture after the event is the resulting state, not the 'antecedent' (preceding) condition.
- Option (c) is incorrect because AMC refers to the state immediately preceding a specific event, not a monthly average.
- Option (d) is incorrect because maximum soil moisture refers to 'field capacity' or 'saturation,' which is a physical limit, not the current condition before a storm.
If a contour trench has a length of 100 m, width of 1 m, and depth of 0.5 m, the total volume of soil excavated is -
A)
25 m3
B)
50 m3
C)
75 m3
D)
100m3
To find the total volume of soil excavated from a contour trench, we treat the trench as a rectangular prism (cuboid). The formula for the volume of a cuboid is: Volume = Length × Width × Depth. Given the values: Length = 100 m, Width = 1 m, and Depth = 0.5 m. Calculation: Volume = 100 m * 1 m * 0.5 m = 50 m³. Therefore, option (b) is correct. Options (a), (c), and (d) are incorrect as they do not match the mathematical product of the given dimensions.
Probable Maximum Precipitation (PMP) is -
A)
the average precipitation over a year
B)
the maximum precipitation expected for a given return period
C)
the theoretically greatest depth of precipitation for a given duration under optimal meteorological conditions
D)
none of the above
Probable Maximum Precipitation (PMP) is a critical concept in hydrology used for the design of high-risk structures like spillways of large dams.
1. **Definition**: PMP is defined as the greatest depth of precipitation for a given duration that is physically possible over a particular drainage basin at a particular time of year. It represents a theoretical upper limit based on the maximum moisture available in the atmosphere and the maximum efficiency of the storm system to convert that moisture into rain.
2. **Why Option (c) is correct**: It accurately describes PMP as the 'theoretically greatest depth' occurring under 'optimal meteorological conditions' (meaning conditions that maximize rainfall).
3. **Why Option (a) is incorrect**: The average precipitation over a year is simply the 'Mean Annual Precipitation,' which is a statistical average, not a maximum limit.
4. **Why Option (b) is incorrect**: Precipitation expected for a given return period (e.g., a 100-year storm) is referred to as 'Design Precipitation' or 'Return Period Precipitation.' PMP is far more extreme than any standard return period storm; it is the absolute physical limit, regardless of the return period.
What is the probability of non-occurrence of 100 mm rainfall in a year if its return period is 15 years?
A)
0.933
B)
0.088
C)
0.067
D)
0.885
Step-by-step solution:
1. **Understand the Return Period (T):** The return period is the average time interval between occurrences of an event of a certain magnitude. Here, T = 15 years.
2. **Calculate the Probability of Occurrence (P):** The probability that a rainfall event of 100 mm (or more) will occur in any given year is given by the formula:
P = 1 / T
P = 1 / 15 ≈ 0.06667
3. **Calculate the Probability of Non-occurrence (q):** The probability of non-occurrence is the complement of the probability of occurrence. It is the probability that the event will NOT happen in a given year:
q = 1 - P
q = 1 - (1 / 15)
q = 14 / 15
q ≈ 0.93333
4. **Conclusion:** Rounding to three decimal places, we get 0.933.
Comparing with options:
- Option (a) 0.933 matches our calculation.
- Option (b) 0.088 is incorrect.
- Option (c) 0.067 represents the probability of occurrence (P), not non-occurrence.
- Option (d) 0.885 is incorrect.
Which of the following combinations for a channel is most suitable to achieve best results in flood management?
A)
Increasing width and roughness
B)
Increasing width and decreasing roughness
C)
Decreasing width and increasing roughness
D)
Decreasing width and roughness
Flood management aims to maximize the discharge capacity (Q) of a channel to prevent overtopping of banks during peak flow events. According to Manning's Equation for open channel flow: Q = (1/n) * A * R^(2/3) * S^(1/2), where Q is discharge, n is the Manning's roughness coefficient, A is the cross-sectional area, R is the hydraulic radius, and S is the slope.
1. Increasing Width: By increasing the width of the channel, the cross-sectional area (A) increases. Since Q is directly proportional to A, a wider channel can carry a larger volume of water for a given depth, thereby reducing the flood stage (water level).
2. Decreasing Roughness: The roughness coefficient (n) is in the denominator of the equation. Decreasing roughness (e.g., by lining the channel with concrete or removing vegetation) reduces the frictional resistance against the flow, which increases the velocity of the water and consequently increases the discharge capacity (Q).
Therefore, the combination of increasing width (to increase area) and decreasing roughness (to increase velocity) provides the maximum possible discharge capacity, making it the most suitable strategy for flood management.
A person of height 1.65 m standing on a cliff of height 20 m above the water level on sea shore can sight a ship at a distance of
A)
10km
B)
18km
C)
20km
D)
15.4m
1. **Identify the total height of the observer's eye level (h):**
The person is standing on a cliff of height 20 m and the person's own height is 1.65 m.
Total height (h) = Height of cliff + Height of person = 20 m + 1.65 m = 21.65 m.
2. **Formula for Distance to the Horizon:**
Due to the curvature of the Earth, the distance (d) to the horizon is given by the formula:
d = 3.855 × √h
Where:
- d is the distance to the horizon in kilometers (km).
- h is the height of the observer's eye above the sea level in meters (m).
3. **Calculation:**
d = 3.855 × √21.65
√21.65 ≈ 4.653
d = 3.855 × 4.653
d ≈ 17.937 km
4. **Conclusion:**
The calculated distance is approximately 17.94 km, which rounds to 18 km.
Comparing with the options:
- (a) 10km: Incorrect.
- (b) 18km: Correct (closest approximation).
- (c) 20km: Incorrect.
- (d) 15.4m: Incorrect (unit is wrong and value is incorrect).
Which one of the following surveys is used to define the property line?
A)
City survey
B)
Cadastral survey
C)
Compass survey
D)
Topographical survey
A Cadastral survey is a specialized type of survey used specifically to establish, define, and record the legal boundaries of land parcels, property lines, and ownership rights. These surveys are essential for land registration, taxation, and legal disputes regarding property ownership.
Analysis of other options:
- a. City survey: This is a general term for surveying urban areas, which may include cadastral elements but also encompasses infrastructure, utilities, and zoning.
- c. Compass survey: This refers to a method of surveying (using a magnetic compass to determine directions) rather than the purpose of the survey. A compass survey could be used to perform a cadastral survey, but it is not the definition of a property line survey.
- d. Topographical survey: This survey is used to determine the relative positions of natural and man-made features on the earth's surface, including contours (elevation changes), rather than legal property boundaries.
The impact load of ship while docking is taken up by
A)
Morning dolphins
B)
Breasting dolphins
C)
Bulkhead
D)
Fixed morning berth
In harbor and port engineering, dolphins are man-made marine structures used to protect the berth or to provide mooring points for ships. There are two primary types of dolphins:
1. **Breasting Dolphins**: These are designed to absorb the kinetic energy (impact load) of a ship as it approaches the berth and pushes against the structure to come to a stop. They are typically equipped with fenders to cushion the impact and prevent damage to both the ship's hull and the structure.
2. **Mooring Dolphins**: These are used to secure the ship's mooring lines (ropes) to keep the ship stationary once it has docked. They are designed to resist the tension (pulling force) of the mooring lines rather than the impact force of the ship's hull.
Therefore, the impact load during docking is specifically taken up by the breasting dolphins.
- Option (a) is incorrect because mooring dolphins handle tension, not impact.
- Option (c) is incorrect as a bulkhead is a retaining wall used to reclaim land from the sea, not specifically for absorbing docking impact.
- Option (d) is incorrect as a fixed mooring berth refers to the general docking area or the mooring facility, but the specific structural element for impact absorption is the breasting dolphin.
What is the unit of payment in MKS system for Earthwork in banking, cutting in road and irrigation channel?
A)
Per m
B)
Per m²
C)
Per m³
D)
Tons
In civil engineering estimation and costing, earthwork refers to the movement, removal, or addition of soil/earth to prepare a site or create a structure.
1. **Nature of Work**: Banking (filling/embankments) and cutting (excavation) in roads and irrigation channels involve three dimensions: length, width, and depth/height.
2. **Measurement Principle**: According to standard measurement codes (such as IS 1200 in India), any work involving the removal or placement of bulk material is measured by volume.
3. **MKS System**: In the MKS (Meter-Kilogram-Second) system, the unit of volume is the cubic meter (m³).
Why other options are incorrect:
- **Per m (Linear meter)**: Used for items like piping, fencing, or cabling where length is the primary factor.
- **Per m² (Square meter)**: Used for surface-area based work such as plastering, painting, or flooring.
- **Tons (Mass)**: Used for materials supplied by weight (like steel or cement), but not for the execution of earthwork in situ.
Which stone is used for buildings situated in industrial towns?
A)
Marble slab
B)
Compact sandstone
C)
Gneiss
D)
Slate
In industrial towns, buildings are frequently exposed to atmospheric pollution, including sulfur dioxide and other acidic gases, which can lead to chemical weathering of building materials. Compact sandstone is preferred for such environments because it is highly durable, possesses high compressive strength, and is generally more resistant to the corrosive effects of industrial pollutants compared to carbonate-based stones.
Analysis of other options:
- Marble slab (a): Marble is composed of calcium carbonate, which reacts readily with acidic rain and industrial pollutants (forming gypsum), leading to rapid deterioration and loss of surface detail.
- Gneiss (c): While durable, gneiss is a metamorphic rock that often has distinct banding (foliation), which can lead to splitting or uneven weathering depending on the orientation of the layers.
- Slate (d): Slate is primarily used for roofing or flooring due to its fissility (ability to split into thin sheets); it is not suitable as a primary structural stone for industrial buildings.
The value of lateral friction or side friction used in the design of horizontal curve as per India Roads Congress guidelines is
A)
0.15
B)
0.24
C)
0.35
D)
0.40
In Transportation Engineering, when a vehicle negotiates a horizontal curve, it is subjected to centrifugal force. To counteract this force and prevent the vehicle from skidding outwards, two mechanisms are used: superelevation (banking of the road) and lateral friction between the tires and the road surface. According to the Indian Roads Congress (IRC) guidelines, the design value for the coefficient of lateral friction (f) is taken as 0.15. This value is used in the fundamental formula for superelevation: e + f = V^2 / (127R), where 'e' is the superelevation, 'f' is the coefficient of lateral friction, 'V' is the speed in kmph, and 'R' is the radius of the curve in meters. Options b, c, and d are incorrect as they exceed the safe design limit recommended by IRC to ensure vehicle stability and passenger comfort.
The curvature of the earth’s surface is taken into account only if the extent of survey is more than
A)
60sq km
B)
160 sq km
C)
260 sqkm
D)
360sqkm
In surveying, there are two primary types of surveys based on the consideration of the Earth's curvature: Plane Surveying and Geodetic Surveying.
1. Plane Surveying: The Earth's surface is treated as a flat plane. This assumption is acceptable for small areas where the curvature of the Earth does not introduce significant errors.
2. Geodetic Surveying: The curvature of the Earth is taken into account to maintain high precision over large areas.
The generally accepted threshold in surveying textbooks (such as those by B.C. Punmia or S.K. Duggal) is that the curvature of the earth can be neglected if the area of the survey is less than 160 square kilometers (or if the linear distance is less than 250 km). If the extent of the survey exceeds 160 sq km, geodetic methods must be employed to ensure accuracy. Therefore, option (b) is the correct technical standard.
The original cost of an equipment Rs 10,000.00. Its salvage value at the end of its total useful life of five years is Rs 1000.00. Its book value at the end of two years of its useful life (as per straight line method of evaluation of depreciation) will be
A)
Rs 8800.00
B)
Rs 7600.00
C)
Rs 6400.00
D)
Rs 5000.00
To find the book value of the equipment at the end of two years using the Straight Line Method (SLM) of depreciation, we follow these steps:
1. **Identify Given Data:**
- Original Cost (C) = Rs 10,000.00
- Salvage Value (S) = Rs 1,000.00
- Total Useful Life (n) = 5 years
- Period for which book value is required (t) = 2 years
2. **Calculate Annual Depreciation (D):**
Under the Straight Line Method, the annual depreciation is constant and is calculated as:
D = (Original Cost - Salvage Value) / Total Useful Life
D = (10,000 - 1,000) / 5
D = 9,000 / 5
D = Rs 1,800.00 per year
3. **Calculate Total Depreciation after 2 years:**
Total Depreciation = Annual Depreciation × Number of years
Total Depreciation = 1,800 × 2 = Rs 3,600.00
4. **Calculate Book Value (BV) at the end of 2 years:**
Book Value = Original Cost - Total Depreciation
BV = 10,000 - 3,600
BV = Rs 6,400.00
Comparing this result with the options:
- Option (a) Rs 8800.00 is incorrect.
- Option (b) Rs 7600.00 is incorrect.
- Option (c) Rs 6400.00 is correct.
- Option (d) Rs 5000.00 is incorrect.
Which one of the following is the part of assumptions made by Terzaghi while developing the mathematical statement of the consolidation process?
A)
The soil is non-homogeneous.
B)
The soil particles and water are incompressible.
C)
The partial deformation of soil is due to partial change in volume.
D)
Co-efficient of permeability is variable during consolidation.
Karl Terzaghi developed the one-dimensional consolidation theory based on several simplifying assumptions to make the mathematical derivation possible. These assumptions include:
1. **Homogeneity**: The soil is assumed to be homogeneous (uniform throughout), which contradicts option (a).
2. **Incompressibility**: Both the soil grains (solid particles) and the pore water are assumed to be incompressible. This means any change in the total volume of the soil mass is solely due to the expulsion of water from the voids. This matches option (b).
3. **Saturation**: The soil is assumed to be fully saturated.
4. **Darcy's Law**: The flow of water is assumed to follow Darcy's Law, and the coefficient of permeability (k) is assumed to remain constant throughout the process, which contradicts option (d).
5. **Deformation**: The deformation is assumed to be one-dimensional (vertical), and the change in volume is directly related to the change in void ratio.
Analysis of options:
- Option (a) is incorrect because Terzaghi assumed the soil is homogeneous.
- Option (b) is correct as it is a fundamental assumption of the theory.
- Option (c) is phrased ambiguously, but the theory focuses on the total volume change resulting from the dissipation of excess pore water pressure.
- Option (d) is incorrect because the coefficient of permeability is assumed to be constant, not variable.
For strengthening a 50 m long and 5 m high straight compound wall built in brick work, which one of the following would be most suitable?
A)
Providing buttresses at certain intervals
B)
Providing a deeper foundation
C)
Using a richer mortar
D)
Using stronger bricks
Step-by-step reasoning: 1. Analysis of the structure: The wall is 50 m long and 5 m high. A height of 5 m for a brick wall is significant, making it susceptible to lateral forces (such as wind pressure or soil pressure if it is a retaining compound wall) and buckling. 2. Identifying the weakness: Long, high walls lack lateral stability. The primary failure mode for such structures is overturning or buckling due to lateral loads. 3. Evaluating the options: (a) Buttresses are external supports built against a wall to provide lateral stability and resist lateral thrust. By providing buttresses at intervals, the effective unsupported length of the wall is reduced, significantly increasing its strength against overturning. (b) A deeper foundation improves bearing capacity but does not prevent the upper part of a 5m high wall from buckling or overturning. (c) Richer mortar increases the bond strength but does not address the geometric instability of a high, slender wall. (d) Stronger bricks increase the compressive strength of the material but do not solve the structural stability issue related to the wall's height-to-thickness ratio. 4. Conclusion: For a wall of these dimensions, structural reinforcement via buttresses is the most effective engineering solution to ensure stability.
What is ∠ABC if FB of line AB is 40° and BB of line BC is 280°?
A)
220°
B)
120°
C)
320°
D)
420°
Step-by-step solution:
1. **Understand the Terms**:
- FB (Fore Bearing) of line AB = 40°.
- BB (Back Bearing) of line BC = 280°.
- We need to find the included angle ∠ABC.
2. **Calculate the Fore Bearing of BC**:
The Back Bearing (BB) of a line is related to its Fore Bearing (FB) by the formula: BB = FB ± 180°.
Given BB of BC = 280°, the FB of BC = 280° - 180° = 100°.
3. **Calculate the Back Bearing of AB**:
To find the angle at point B, we need the bearings of the two lines meeting at B (AB and BC).
The FB of AB is 40°, so the BB of AB (which is the bearing from B to A) = 40° + 180° = 220°.
4. **Calculate the Included Angle ∠ABC**:
The included angle at a station is the difference between the bearing of the next line (FB of BC) and the bearing of the previous line (BB of AB).
Included Angle = (Bearing of BC) - (Bearing of BA)
Included Angle = 100° - 220° = -120°.
5. **Normalize the Angle**:
Since bearings are measured clockwise from North, if the result is negative, we add 360° to find the interior/exterior angle.
-120° + 360° = 240° (This is the exterior angle).
The interior angle ∠ABC = 360° - 240° = 120°.
Alternatively, using the formula: Included Angle = FB of next line - BB of previous line.
Angle = 100° - 220° = -120°. Taking the absolute difference or adjusting for the circle: |100° - 220°| = 120°.
Therefore, the correct option is (b) 120°.
Bar charts are suitable for
A)
Minor works
B)
Major works
C)
Both minor works and major works
D)
Nether minor works nor major works
A Bar Chart (also known as a Gantt Chart) is a scheduling tool that represents activities against a time scale.
1. **Characteristics of Bar Charts**: They are simple to construct and easy to understand. However, they do not show the interdependencies (logical relationships) between activities. If one activity is delayed, the impact on subsequent activities is not automatically reflected.
2. **Suitability for Minor Works**: Because of their simplicity and lack of complex dependency tracking, bar charts are ideal for small-scale or 'minor works' where the number of activities is limited and the sequence is straightforward.
3. **Unsuitability for Major Works**: For large-scale or 'major works', projects involve hundreds of interdependent activities. In such cases, the lack of dependency mapping in bar charts makes them inadequate. For major works, Network Techniques like CPM (Critical Path Method) or PERT (Program Evaluation and Review Technique) are used because they explicitly define the critical path and activity relationships.
Therefore, while they can be used for any project, they are specifically 'suitable' (most effective/appropriate) for minor works.
The critical activity has:
A)
Nonmal float
B)
Maximum float
C)
Minimum float
D)
Zero float
In project management and network analysis (CPM - Critical Path Method), the 'Critical Path' is defined as the longest sequence of activities in a project network that determines the shortest possible project duration.
1. **Definition of Float**: Float (or slack) is the amount of time that a task in a project network can be delayed without causing a delay to subsequent tasks or the overall project completion date.
2. **Critical Activity**: An activity is considered 'critical' if any delay in its start or finish date directly impacts the project completion date.
3. **Mathematical Relation**: Total Float = Latest Start (LS) - Earliest Start (ES) or Latest Finish (LF) - Earliest Finish (EF). For activities on the critical path, the Earliest Start is equal to the Latest Start, and the Earliest Finish is equal to the Latest Finish.
4. **Conclusion**: Therefore, the float for a critical activity is exactly zero. If an activity has a non-zero float, it is a non-critical activity.
Comparing the options:
- (a) 'Nonmal float' is likely a typo for 'Normal float', which applies to non-critical activities.
- (b) 'Maximum float' refers to activities with the most flexibility, the opposite of critical activities.
- (c) 'Minimum float' is vague; while zero is a minimum for standard projects, 'Zero float' is the precise technical term.
- (d) 'Zero float' is the standard definition for a critical activity.
When the product of rock weathering is not transported as sediment but remains in place, is called
A)
Alluvial soil
B)
Residual soil
C)
Glacial soil
D)
Red soil
In soil mechanics and geology, soils are classified based on their origin and transport mechanism.
1. **Residual Soil**: This type of soil is formed by the weathering of bedrock in situ. When the parent rock undergoes chemical or physical weathering, the resulting particles remain at the site of origin without being transported by agents like water, wind, or ice. This matches the description in the question.
2. **Alluvial Soil (Option a)**: This is a type of transported soil. It is deposited by running water (rivers/streams) in floodplains or deltas. Since it is transported, it does not fit the criteria.
3. **Glacial Soil (Option c)**: This is also a transported soil, deposited by the movement and melting of glaciers (e.g., till). Since it is transported, it does not fit the criteria.
4. **Red Soil (Option d)**: This refers to a soil color/type usually resulting from high iron oxide content. While some red soils can be residual (like laterites), 'Red soil' is a descriptive classification of soil properties/composition rather than a classification based on the mechanism of transport vs. in-situ formation.
Slack time in PERT analysis ;
A)
can never be greater then zero
B)
is always zero for critical activities
C)
can never be less then zero
D)
is minimum for critical events
In PERT (Program Evaluation and Review Technique) and CPM (Critical Path Method), 'Slack' (or Float) refers to the amount of time an activity or event can be delayed without delaying the project completion date.
1. **Definition of Critical Path**: The critical path is the longest path through the network. Any delay in an activity on this path directly delays the project.
2. **Slack Calculation**: Slack is calculated as the difference between the Latest Allowable Time (Late Start/Finish) and the Earliest Expected Time (Early Start/Finish).
3. **Critical Activities**: For activities on the critical path, the earliest start time is equal to the latest start time, and the earliest finish time is equal to the latest finish time. Therefore, the slack is exactly zero.
Evaluating the options:
- **Option a**: Incorrect. Slack can be greater than zero for non-critical activities.
- **Option b**: Correct. By definition, critical activities have zero slack.
- **Option c**: Incorrect. In some advanced scheduling scenarios (like when a fixed deadline is imposed that is shorter than the critical path), 'negative slack' can occur, indicating the project is behind schedule.
- **Option d**: Incorrect. While slack is minimum (zero) for critical events, the phrasing 'is always zero for critical activities' is the standard technical definition used in construction management exams.
Platforms built for ships to come close to the shore are known as
A)
wharves
B)
locks
C)
ports
D)
none
Step-by-step reasoning:
1. Analysis of the term 'Wharves' (plural of wharf): A wharf is a man-made structure (platform) built along a shoreline or projecting into the water, designed specifically to allow ships to dock, moor, and load or unload cargo and passengers. This matches the description in the question.
2. Analysis of 'Locks': A lock is a device used for raising and lowering boats between stretches of water of different levels on river and canal waterways. It is a navigation tool, not a docking platform.
3. Analysis of 'Ports': A port is a broad geographical area or a city that possesses a harbor and the necessary infrastructure (including wharves, warehouses, and customs) to handle maritime trade. While a port contains wharves, the specific 'platform' itself is the wharf.
4. Conclusion: Since the question asks for the specific platform built for ships to come close to the shore, 'wharves' is the most accurate technical term.