← MES Jr. Grade
Past Questions
The water contamination that may be concentrated by Algae or other water organism and upon eaten by fishes can get further concentration is :-
A)
Lead
B)
Radioactive isotopes
C)
Fluoride
D)
Mercury
This refers to bioaccumulation/biomagnification in aquatic food chains. Certain contaminants are taken up by algae and small organisms, then become more concentrated in fish that eat them. Mercury is a classic example, especially as methylmercury. Lead and fluoride do not characteristically biomagnify this way, and radioactive isotopes are not the standard answer to this specific water-contamination question.
Pelton wheel turbine is an example of :-
A)
Mix flow turbine
B)
Axial flow turbine
C)
Radial flow turbine
D)
Tangential flow turbine
A Pelton wheel is an impulse turbine in which the water jet strikes the buckets tangentially to the runner. Hence it is classified as a tangential flow turbine. Mix flow, axial flow, and radial flow turbines describe other turbine flow directions, not the Pelton wheel.
The detention type of Dam among the followings is :-
A)
Spillway
B)
Dike
C)
Weir
D)
Barrage
A detention type dam is meant to temporarily store flood water and release it later in a controlled manner. Among the given options, a dike serves as a detention structure. A spillway is an outlet for excess water, a weir is generally used to raise water level or measure flow, and a barrage is a low-head diversion structure across a river.
The growth of a community with limited land area for future expansion might be modelled using the :-
A)
Declining growth model
B)
Geometric model
C)
Uniform percentage growth model
D)
Arithmetic constant growth rate model
A community with limited land area cannot grow indefinitely at an increasing percentage rate. When space and resources are constrained, growth tends to become linear, i.e., it increases by a constant amount each period. This is represented by the arithmetic constant growth rate model. The geometric and uniform percentage growth models imply exponential-type growth, which is unsuitable for limited land expansion, while the declining growth model describes slowing growth rather than the basic model for limited-area community growth.
Which of the followings is not an accessories of an intake structure of Hydro-power plant :-
A)
Rakes
B)
Penstock closing gates with hoist
C)
Forebay
D)
Trash rack
An intake structure of a hydropower plant commonly includes accessories such as trash racks, rakes, and sometimes a forebay as part of the water-conveyance and screening arrangement. A penstock closing gate with hoist, however, is associated with the penstock/control arrangement, not the intake structure itself. Therefore, it is the item that is not an accessory of the intake structure.
The frictional resistance in the laminar flow through pipes is independent of :-
A)
Nature of the surface in contact
B)
Velocity of flow
C)
Area of surface in contact
D)
Temperature of the flowing fluid
In laminar flow through pipes, frictional resistance is governed mainly by the viscosity of the fluid and the velocity distribution. It is directly related to the velocity of flow and the area of surface in contact, and it also varies with temperature because temperature changes viscosity. In ideal laminar pipe flow, the frictional resistance is independent of the nature of the surface in contact, provided the pipe is hydraulically smooth and the flow remains laminar. Hence, option (a) is correct.
The actual thermodynamic process which is approximated by the relation pvn = Constant, where n is a positive constant is called :-
A)
Isothermal process
B)
Adiabatic process
C)
Polytropic process
D)
Isentropic process
The relation pV^n = constant, where n is a positive constant, defines a polytropic process. Many real thermodynamic processes can be approximated by this equation depending on the value of n. For example, n = 1 gives an isothermal process, and n = γ gives an adiabatic process. Therefore, the correct answer is polytropic process.
A reservoir primarily used to store the excess water during the period of large supplies and release it gradually as and when it is needed is :-
A)
Storage reservoir
B)
Flood control reservoir
C)
Distribution reservoir
D)
Multipurpose reservoir
A storage reservoir is designed to retain excess water during periods of high inflow or large supply and then release it gradually when required. A flood control reservoir is mainly meant to reduce flood peaks, a distribution reservoir stores water for immediate distribution in a supply system, and a multipurpose reservoir serves several functions at once. Hence, the correct answer is Storage reservoir.
In a compressible fluid flow where the velocity of flow is reduced to zero and the kinetic energy is converted into pressure energy is the :-
A)
Mach line
B)
Stagnation point
C)
Zone of silence
D)
Zone of action
In compressible flow, when the fluid velocity becomes zero, the moving fluid is brought to rest and its kinetic energy is converted into pressure energy. This location is called a stagnation point.
Why others are incorrect:
- (a) Mach line: a line associated with Mach waves in supersonic flow.
- (c) Zone of silence: region outside the Mach cone where disturbance has not reached.
- (d) Zone of action: not the term used for this condition in fluid mechanics.
So, the correct answer is stagnation point.
If river flow permits, the hydro-power plant that can operate both as peak-load and base-load plant is :-
A)
Run-of-river plant with pondage
B)
Pumped storage plant
C)
Reservoir plant
D)
Tidal plants
A reservoir hydro-power plant can store a large quantity of water and regulate discharge as needed. Because of this storage, it can generate continuously as a base-load plant and also supply extra power during peak demand. A run-of-river plant with pondage has only limited storage, so its peaking ability is restricted. A pumped storage plant is mainly used for peak-load support, not as a true base-load plant. Tidal plants depend on tidal cycles and are not suitable for both base-load and peak-load operation.
The simplest multi-cellular micro-organism that require a relatively high dissolved oxygen and that their presence is a good indication of relative stability of a treated waste is:-
A)
Rotifers
B)
Algae
C)
fungi
D)
Protozoa
Rotifers are among the simplest multicellular microorganisms found in well-treated wastewater. They require relatively high dissolved oxygen and their presence indicates that the treated waste is relatively stable. Algae are photosynthetic organisms, fungi are not typically used as an indicator of treated waste stability, and protozoa are unicellular rather than multicellular.
If the working head available in hydro-power plant is less than 30 m, which of the following turbine would be suitable for the project :-
A)
Pelton wheel
B)
Turgo-impule wheel
C)
Kaplan turbine
D)
Modern Francis turbine
Hydraulic turbines are selected according to available head. Kaplan turbines are low-head, high-discharge turbines, typically suitable for heads below about 30 m. Pelton wheel and Turgo impulse wheel are impulse turbines used for high-head sites, while Francis turbines are generally used for medium heads, not the lowest-head range. Therefore, for working head less than 30 m, the correct choice is Kaplan turbine.
At what temperature that sewage will change from fresh to stale in 2 to 6 hours :-
A)
about 15oC
B)
about 18oC
C)
about 20oC
D)
about 22oC
In sewage engineering, the rate of septic decomposition increases with temperature. Standard environmental engineering texts note that sewage may change from fresh to stale in about 2 to 6 hours at around 20°C. At lower temperatures this change takes longer, while at higher temperatures it occurs faster. Hence, the correct option is (c) about 20°C.
In the principle of plain sedimentation, discrete particles having settling velocity lower than SOR are
A)
entirely removed
B)
partially get removed
C)
remain in suspension
D)
removed in direct proportion to the ratio of their settling velocity and vertical velocity
In plain sedimentation, a particle is fully removed only if its settling velocity is greater than or equal to the surface overflow rate (SOR). If its settling velocity is lower than SOR, only a fraction of the particles will settle out before leaving the tank, so they are partially removed. Hence, option (b) is correct. Option (a) is wrong because complete removal does not occur. Option (c) is wrong because such particles do not all remain in suspension. Option (d) is not the general principle for discrete settling in plain sedimentation.
The canal outlet in which the discharge is affected by fluctuation in water level of distributing channel but not affected by water level fluctuation of the field channel is :-
A)
Non-modular outlet
B)
Flexible outlet
C)
Rigid module
D)
Both (b) & (c)
A rigid module outlet is designed so that its discharge depends on the water level in the distributing channel, but it is not affected by fluctuations in the water level of the field channel. Hence it matches the given description.
Why the others are incorrect:
- Non-modular outlet: discharge is affected by water levels on both sides.
- Flexible outlet: discharge is generally affected by the water level in the field channel as well.
- Both (b) & (c): only rigid module fits the statement, not flexible outlet.
The method of evaporation estimation involving writing the hydrological continuity equation for the lake and determining the evaporation from a knowledge or estimation of other variables is :-
A)
Energy-Budget method
B)
Mass-Transfer method
C)
Water-Budget method
D)
Colorado Sunken pan method
The method described uses the hydrological continuity equation for a lake and estimates evaporation as the unknown term after accounting for inflow, outflow, rainfall, seepage, and change in storage. This is the Water-Budget method. The Energy-Budget method is based on heat balance, the Mass-Transfer method on vapor transport by wind, and the Colorado Sunken pan method is a pan evaporation measurement technique.
Choose which of the following equation is independent of the system of units (SI,Metric or English system) :-
A)
Manning’s equation
B)
Chezy’s equation
C)
Laminar flow in pipes
D)
Kennedy’s equation
Manning’s equation is independent of the system of units because it is commonly written with the roughness coefficient n taking values adjusted for the chosen unit system, but the equation itself is not tied to a specific unit form in the way some others are. Chezy’s and Kennedy’s equations involve coefficients that depend on units, and laminar flow in pipes is not a unit-independent empirical flow equation in the same sense. Hence, the correct answer is Manning’s equation.
The speed of the Generator in hydro-power plant can be maintained constant only if the speed of the turbine is constant, equal to the one given by the relation (where p is the number of pair of poles for the Generator and f is the frequency for power generated in cycles per second) :-
A)
60f/p
B)
70/p
C)
60/p½
D)
70/p½
In a hydro-power plant, the generator must run at synchronous speed to produce alternating current of frequency f. The synchronous speed is given by N = 120f/P, where P is the total number of poles. Since the question uses p as the number of pairs of poles, P = 2p. Therefore, N = 120f/(2p) = 60f/p. Hence, the correct option is (a). The other options do not match the standard synchronous speed formula.
According to Indian standard recommendation, the uplift pressure in a Gravity dam is assumed to act over :-
A)
100 % of the area
B)
75% of the area
C)
At toe plus 1/3rd the difference of hydrostatic pressure at heel and toe
D)
At heel plus 1/3rd the difference of hydrostatic pressure at heel and toe
In gravity dam analysis as per Indian standard recommendations, uplift pressure is generally assumed to act over 75% of the base area. This reduced-area assumption accounts for the likely effectiveness of drainage and relief measures in lowering uplift. Hence, option (b) is correct. Options (c) and (d) describe the *distribution* of uplift pressure along the base (triangular/trapezoidal pattern), but the question asks about the *area over which uplift is assumed to act*.
The probable maximum flood is :-
A)
an extremely large but physically possible flood in the region
B)
the standard project flood of an extremely large river
C)
a flood adopted in the design of all kinds of spillways
D)
a flood adopted in all hydraulic structures
The probable maximum flood (PMF) is defined as the largest flood that is considered reasonably possible at a site, based on the most severe combination of meteorological and hydrological conditions. It is not a standard project flood, and it is not universally adopted for all spillways or all hydraulic structures. Hence, option (a) is correct.
The available hydraulic power possess by a particular stream / river can be assessed in kilowatt-hours (kwh) using the relation, where is the efficiency of hydro power station and others are in usual notations :-
A)
E= 9.81Q(H-h)
B)
E= Q(H-h)
C)
E= 9.81Q(H-h) X T
D)
E= Q(H-h) X T
The hydraulic power available from a stream is proportional to discharge Q, net head (H−h), efficiency η, and time T. Since power in kW is 9.81Q(H−h)η, the energy available in kWh is this power multiplied by time T. Therefore the correct relation is E = 9.81Q(H−h)η × T. Options (a) and (b) give only power-like expressions without time, and (d) misses the 9.81 factor.
Sulfurous smog is caused almost entirely by :-
A)
Motor vehicles
B)
Power plants
C)
Municipal waste
D)
Combination of (a) & (c)
Sulfurous smog (industrial smog or London smog) is mainly produced by the burning of sulfur-containing coal and fuel oil, which releases sulfur dioxide and smoke. This type of pollution is associated almost entirely with power plants and industrial combustion sources. Motor vehicles are more strongly linked with photochemical smog, and municipal waste is not the primary cause of sulfurous smog.
Typhoid out break can happen due to infected milk and other foods, particularly oysters, salads and other uncooked food, the epidemic could be waterborne when :-
A)
it is scattered over the city
B)
dysentery accompany or precede typhoid
C)
All classes and ages of people are affected
D)
All of these
Typhoid outbreaks due to contaminated food or water are often recognized as waterborne when the disease is widespread across the city, when dysentery accompanies or precedes typhoid, and when people of all classes and ages are affected. Since all three conditions indicate a common water source affecting many users, the correct answer is "All of these".
A part of sewer system that receives the discharge from the collecting system and conducts it to the treatment plant or point of final disposal is :-
A)
Sewer outfall
B)
Relief sewer
C)
Lateral sewer
D)
Intercepting sewer
A sewer outfall is the part of the sewer system that carries sewage from the collecting system to the treatment plant or the final disposal point.
Why others are incorrect:
- Relief sewer: used to relieve excess flow in the sewer system.
- Lateral sewer: a small sewer that collects wastewater from individual properties and connects to larger sewers.
- Intercepting sewer: intercepts sewage from several sewers and conveys it to a treatment/disposal point, but the standard definition in this question matches sewer outfall.
In which type of the following flow of fluid, viscosity plays a significant part :-
A)
Turbulent flow
B)
Laminar flow
C)
Rotational flow
D)
Irrotational flow
Viscosity is the property of a fluid that resists relative motion between adjacent layers. In laminar flow, fluid moves in smooth layers and the viscous effect is significant in determining the motion. In turbulent flow, inertial effects dominate more than viscosity, while rotational/irrotational refer to the nature of flow rotation, not the dominance of viscosity. Hence, the correct answer is laminar flow.