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Past Questions — 2016
As per CPWD Specification, the use of chips in hearting stones in a Regular Coursed Rubble Stone masonry (1* sort) shall not exceed X % of the quantity of stone masonry. Find the correct replacement for X.
A)
10
B)
15
C)
20
D)
25
As per CPWD specification for Regular Coursed Rubble Stone Masonry (1st sort), the chips used in hearting stones shall not exceed 15% of the quantity of stone masonry. Therefore, option (b) is correct. The other values 10%, 20%, and 25% do not match the specified CPWD limit.
For complete hydration of cement, the water cement ratio needed is
A)
less than 0.25
B)
more than 0.25 but less than 0.35
C)
more than 0.35 but less than 0.45
D)
more than 0.45 but less than 0.60
For complete hydration of cement, the minimum water-cement ratio required is about 0.38 by weight for full chemical hydration, but in practice the commonly cited range for sufficient water for hydration is around 0.25 to 0.35 depending on cement type and conditions. Among the given options, the closest correct range is (b). Option (a) is too low for complete hydration, while (c) and (d) are higher than the amount needed for hydration and include extra water that does not contribute to hydration.
Which of the following stones has maximum % water absorption by volume?
A)
Shale
B)
Granite
C)
Slate
D)
Quartzite
Water absorption by volume is highest in porous stones. Shale is a sedimentary rock with comparatively high porosity and absorbs more water than dense stones like granite, slate, and quartzite. Granite is very hard and low-porosity, while slate and quartzite are also much less absorptive than shale.
Hydrogen cooling employed in large thermal power plant alternator:
A)
Increases the insulation life
B)
Decreases the insulation life
C)
Does not effect the insulation life
D)
None of these
Hydrogen is used as a cooling medium in large alternators because it has high thermal conductivity and low density, so it removes heat efficiently while reducing windage losses. Better cooling keeps the machine temperature lower, and lower operating temperature improves insulation life. Hence, the correct answer is that hydrogen cooling increases insulation life.
For the flue gas flow, tick the correct sequence:
A)
Boiler-Air preheater- economizer- ID fan- Chimney
B)
Boiler- ID fan -Air preheater- Economizer- Chimney
C)
Boiler- Economizer- Air preheater- ID fan- Chimney
D)
None of these
In a thermal power plant, flue gas leaves the boiler and then passes through the heat-recovery equipment in this order: first the air preheater, then the economizer, after which the induced draught (ID) fan draws the gas to the chimney. Therefore, option (a) matches the correct sequence. Options (b) and (c) place the ID fan or heat exchangers in the wrong order.
Stability of a system is not affected by
A)
Reactance of line
B)
Losses
C)
Reactance of generator
D)
Output torque
In power system stability, the important factors are the reactances of the generator and transmission line, and the power/torque output characteristics. These directly affect the maximum power transfer and synchronizing capability of the system. Line reactance and generator reactance reduce stability margin by limiting power transfer. Output torque is also related to the mechanical-electrical balance and hence affects stability. Losses, however, mainly affect efficiency and power delivered, and are usually neglected in basic stability analysis; therefore, stability is not affected by losses.
Economizer is normally employed when boiler pressure exceeds:
A)
70 kg/cm2
B)
50 kg/cm2
C)
30 kg/cm2
D)
can be used for all pressures
An economizer recovers heat from flue gases to preheat the feedwater, improving boiler efficiency. It is normally considered especially useful in medium- and high-pressure boilers, and standard power plant engineering references commonly state that economizers are employed when boiler pressure exceeds about 30 kg/cm². Options (a) 70 kg/cm² and (b) 50 kg/cm² are too high for the usual threshold, while (d) is incorrect because economizers are not equally emphasized for all pressures.
In order to increase the limit of distance of transmission line
A)
series resistances are used
B)
synchronous condensers are used
C)
shunt capacitors and series reactors are used
D)
series capacitors and shunt reactors are used
To increase the transmission distance/capacity of a line, reactive power compensation is used. Series capacitors reduce the effective line reactance, improving voltage regulation and allowing power to be transmitted over longer distances. Shunt reactors help absorb excess reactive power, especially on long lightly loaded lines, controlling overvoltage. Hence, the correct choice is series capacitors and shunt reactors. The other options are incorrect because series resistance increases losses, and synchronous condensers or shunt capacitors/series reactors are not the standard combination for increasing transmission distance.
In steam power plant which of the following component needs more maintenance:
A)
Condenser
B)
Boiler
C)
Turbine
D)
Coal carrying system
In a steam power plant, the boiler needs the most maintenance because it operates at high temperature and pressure, and it is directly exposed to issues like scaling, corrosion, soot deposition, tube failure, and water-treatment problems. These factors make boiler maintenance more frequent and demanding than the other components. The condenser generally requires less maintenance, the turbine needs careful upkeep but usually not as much routine maintenance as the boiler, and the coal handling system mainly involves mechanical wear and dust-related issues, which are important but typically less severe than boiler maintenance.
The relation between traveling voltage wave and current wave is
A)
e = i (L/C) 1/2
B)
e = i (C/L) 1/2
C)
e = i (iL/C) 1/2
D)
(L/iC) ½
For a lossless transmission line, the ratio of traveling voltage wave to current wave is the characteristic impedance Z0 = √(L/C). Hence e / i = √(L/C), or e = i√(L/C). Option (a) matches this relation. Option (b) is the inverse, and the other options are not correctly formed.
In thermal power plants the condenser used is of:
A)
surface type
B)
jet type
C)
can be both surface type and jet type
D)
none of these
In thermal power plants, condensers may be of two main types: surface condensers and jet condensers. Surface condensers are commonly used in modern power plants because they keep the condensate and cooling water separate, allowing reuse of the condensate in the boiler. Jet condensers are also used in some installations, though less commonly, where direct contact between steam and cooling water is acceptable. Therefore, the correct answer is that the condenser can be both surface type and jet type.
On earthen roads, camber should preferably be
A)
1 in 20 to 1 in 24
B)
1 in 20 to 1 in 30
C)
1 in 30 to 1 in 40
D)
1 in 10 to 1 in 15
For earthen roads, a relatively steeper camber is preferred so that rainwater drains off quickly and does not soften or erode the road surface. Standard highway engineering practice recommends camber about 1 in 20 to 1 in 30 for earthen roads. A flatter camber, such as 1 in 30 to 1 in 40, is more suitable for higher-quality paved surfaces, while 1 in 10 to 1 in 15 is excessively steep.
Earth work in formation cutting is measured in
A)
Cum.
B)
Rm.
C)
Sqm.
D)
Feet
Earthwork in formation cutting is measured by volume, since the quantity depends on length, width, and depth of cutting. Therefore the correct unit is cubic metre (Cum.). Rm. is used for running length, Sqm. for area, and Feet is not the standard unit for earthwork measurement.
With a percentage increase of carbon in steel, decreases its
A)
strength
B)
hardness
C)
brittleness
D)
ductility
As the percentage of carbon in steel increases, the steel becomes harder and stronger but loses its ability to deform plastically. Therefore, ductility decreases. Brittleness generally increases, not decreases. So the correct answer is ductility.
On a steel structures the dead load is the the weight of
A)
Steel works
B)
Material fastened to steel work
C)
Material supported permanently
D)
All the above
In steel structures, dead load means the permanent load acting on the structure. It includes the self-weight of the steel works, any materials fastened to the steel work, and any materials permanently supported by it. Therefore, all the listed items are part of dead load.
As per IRC-52-2001 the desirable road land width for National & State highway in open area is
A)
18.00 m
B)
20.00 m
C)
24.00 m
D)
30.00 m
As per IRC-52-2001, the desirable road land width for National and State highways in open area is 24.00 m. This is the standard recommended width for highway land in open terrain. The other options are not the prescribed desirable width for this category.
In Concrete work, item shall be measured in cubic meter and no deduction shall be made for
A)
Opening up to 0.10 sq. m.
B)
Volume occupied by reinforcement
C)
Small voids not exceeding 40 sq.cm each in cross section
D)
All of these
In concrete work, measurement is generally taken by volume in cubic metres. As per standard estimation rules, no deduction is made for small openings/voids up to the specified limit and also for the volume occupied by reinforcement. Here, opening up to 0.10 sq. m., volume occupied by reinforcement, and small voids not exceeding 40 sq. cm each in cross section are all cases where no deduction is made. Therefore, the correct answer is 'All of these'.
For making detailed estimate of the building the following method can be used
A)
Long and short wall method
B)
Centre line method
C)
Crossing method
D)
All of these
Detailed estimate of a building can be prepared by several standard methods, depending on the plan and type of construction. The long wall and short wall method, centre line method, and crossing method are all used in estimation and costing for buildings. Hence, the correct answer is 'All of these'.
The distance between c.g of compression and c.g. of tension flanges of a plate girder is known as
A)
Overall depth
B)
Effective depth
C)
Clear depth
D)
Actual depth
In a plate girder, the distance between the centre of gravity (c.g.) of the compression flange and the centre of gravity (c.g.) of the tension flange is called the **effective depth**. It is the depth that effectively resists bending moment.
- **Overall depth**: total depth of the girder from top to bottom, including flange thicknesses.
- **Clear depth**: usually the distance between the inner faces of flanges/web portions, not between c.g.s.
- **Actual depth**: a general term, but not the standard structural term for this definition.
Hence, the correct answer is **(b) Effective depth**.
Sewer manholes are generally provided at
A)
the change of gradient
B)
the change of direction
C)
the junction of sewer
D)
all of these
Sewer manholes are provided at points where inspection, cleaning, or maintenance is needed. This includes: (1) change of gradient, because flow conditions change; (2) change of direction, because bends need access for maintenance; and (3) junctions of sewers, where multiple lines meet. Therefore, the correct answer is all of these.
Work schedule is
A)
Detail list of works to be taken up for a specified period of time
B)
Detail list of works that has been completed
C)
Important list of work
D)
None of these
A work schedule in estimation and costing means a planned, detailed list of works to be executed within a specified period. It is used to organize and control construction activities. Option (b) refers to completed works, not a schedule. Option (c) is too vague and not the standard definition. Therefore, (a) is correct.
In Percentage rate contract the
A)
payments to the contractor are to be made item wise rate
B)
payments to the contractor are made in percentage of the work done value
C)
payment to the contractor is made after completion of the work
D)
none of these
In a percentage rate contract, the contractor quotes a percentage above or below the estimated rate schedule. Payment is then made by applying that percentage to the value of work actually executed. So the contractor is paid in percentage of the work done value. Option (a) describes item-rate contract, and (c) describes lump-sum or completion-based payment, so they are incorrect.
The sludge does not contain waste water from
A)
Bath rooms
B)
Wash basins
C)
Kitchen sinks
D)
Toilets
Sludge is the semi-solid residue that settles in wastewater treatment. Wastewater from bath rooms, wash basins, and kitchen sinks contributes to sewage and sludge. Toilets mainly discharge excreta-rich sewage, but the question asks which one sludge does not contain wastewater from; in standard sanitary engineering terminology, sludge is not associated with wastewater from toilets in this context. Hence, the correct option is Toilets.
The ration of longitudinal stress to strain within elastic limit is known as
A)
Tangent modulus of elasticity
B)
Bulk modulus of elasticity
C)
Shear modulus of elasticity
D)
Modulus of elasticity
Within the elastic limit, the ratio of longitudinal stress to longitudinal strain is called Young's modulus, also known as the modulus of elasticity. The tangent modulus is used beyond the proportional limit, the bulk modulus relates volumetric stress and strain, and the shear modulus relates shear stress and shear strain.
For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed
A)
3 PPm
B)
4 PPm
C)
5 PPm
D)
6 PPm
Fish generally require dissolved oxygen of about 5 mg/L (ppm) or more for safe survival in a river stream. Below this level, stress increases and many species may not survive. Hence, among the given options, 5 ppm is the prescribed minimum.