← MES Jr. Grade
Past Questions — 2016
The delivery valve, while starting centrifugal pump, is kept
A)
fully closed
B)
fully open
C)
half open
D)
in any position
A centrifugal pump should be started with the delivery valve fully closed to reduce the load on the motor and prevent excessive starting current. After the pump reaches operating speed, the delivery valve is opened gradually. If it were left open at start, the pump would need to handle the full discharge immediately, causing a heavy starting load. Hence, option (a) is correct.
In sewage having fully oxidised organic matter, the nitrogen exists in the form of
A)
nitrites
B)
nitrates
C)
free amonia
D)
aluminoid nitrogen
In sewage, as organic matter becomes fully oxidised, the nitrogen undergoes nitrification and is ultimately present mainly as nitrates. Free ammonia appears in the early stages of decomposition, nitrites are intermediate products, and aluminoid nitrogen is organic/undecomposed nitrogen, not the fully oxidised form.
Rain simulators are used for the determination of
A)
infiltration capacity
B)
evaporation
C)
run off
D)
precipitation
Rain simulators (rainfall simulators) are used to apply a controlled artificial rainfall over a soil surface and study how much water enters the soil. This helps determine the infiltration capacity. They are not primarily used to measure evaporation, runoff directly, or natural precipitation.
Specific speed of a Pelton wheel turbine ranges from
A)
12 to 70
B)
80 to 400
C)
300 to 1000
D)
1000 to 1200
The specific speed of a Pelton wheel is low because it is an impulse turbine designed for high head and low discharge. Standard ranges are: Pelton wheel about 12–70, Francis turbine about 80–400, and Kaplan turbine about 300–1000 (sometimes slightly higher). Therefore, the correct range for a Pelton wheel is 12 to 70. The other options correspond to Francis or Kaplan-type turbines, not Pelton.
If requirements of net positive suction head (NPSH) for a given pump are not satisfied, the pump will
A)
consume more power
B)
get cavitated
C)
not develop head
D)
have a low efficiency
Net Positive Suction Head (NPSH) is the pressure head available at the pump suction above the vapour pressure head of the liquid. If the required NPSH is not satisfied, the pressure at the pump inlet falls below vapour pressure, bubbles form, and cavitation occurs. This can damage the pump and cause noise and vibration. Hence, the correct answer is (b) get cavitated. The other options are not the direct consequence of inadequate NPSH.
For standing crops in undulating sandy fields, the best method of irrigation is
A)
sprinkler irrigation method
B)
furrow method
C)
free flowing method
D)
check method
For standing crops in undulating sandy fields, sprinkler irrigation is best because it can apply water uniformly over uneven land and sandy soil without causing excessive runoff or deep percolation losses. Furrow, free-flowing, and check methods are more suitable for level fields and generally require smoother land conditions. Hence, the correct answer is sprinkler irrigation method.
Which of the following turbines is suitable for specific speed ranging from 300 to 1000 and heads below 30 m?
A)
Francis
B)
Propeller
C)
Pelton wheel
D)
Kaplan
Turbines are selected based on specific speed and head. For low heads below about 30 m and high specific speed in the range of 300 to 1000, a propeller turbine is suitable. Pelton wheel is used for high heads and low specific speed, Francis is for medium head and medium specific speed, and Kaplan is also a low-head turbine but is generally associated with very high specific speed values beyond this range.
A pitot tube is used for measuring
A)
pressure of flow
B)
velocity of flow
C)
flow rate
D)
total energy
A Pitot tube measures the velocity of a moving fluid by comparing the stagnation pressure at the tube opening with the static pressure of the flow. Using Bernoulli’s principle, this pressure difference is converted into flow velocity. It does not directly measure flow rate or total energy.
The sludge does not contain waste water from
A)
bathrooms
B)
wash basins
C)
kitchen sinks
D)
toilets
Sludge is the settled solid/semi-solid material collected from wastewater treatment, and the question is asking which wastewater source is not included in sludge. Wastewater from bathrooms, wash basins, and kitchen sinks is generally considered greywater. Toilets produce blackwater containing fecal matter and urine, which is not referred to as sludge from these sources in this context. Therefore, the correct answer is toilets.
The sewer which transports the sewage to the point of treatment is called
A)
main sewer
B)
lateral sewer
C)
branch sewer
D)
out-fall sewer
An out-fall sewer is the sewer that carries sewage from the sewerage system to the point of treatment or disposal, usually the treatment plant. A main sewer collects sewage from branch and lateral sewers, but it does not specifically mean the sewer leading to treatment. Therefore, the correct answer is out-fall sewer. Lateral and branch sewers are smaller collecting sewers within the network.
Equation of continuity of flow is based on the principle of conservation of
A)
mass
B)
energy
C)
force
D)
momentum
The equation of continuity in fluid mechanics is derived from the principle of conservation of mass. It states that for steady flow, the mass flow rate remains constant along a streamtube. Hence, if area changes, velocity changes inversely to keep mass conserved. It is not based on energy, force, or momentum.
In gravity canals, Full Supply Level ( F.S.L ) is always
A)
at the G.L.
B)
4 to 5 m above the G.L.
C)
below the G.L.
D)
a few cm above the G.L.
In a gravity canal, water flows by gravity from a source that is usually at a higher elevation. Therefore, the canal bed and full supply level are generally kept below the ground level for efficient flow and economical construction. So F.S.L. in gravity canals is below the G.L. Options (a), (b), and (d) are not generally correct for gravity canals.
Type of canal constructed for diversion of flood water of rivers is
A)
drains
B)
inundation canals
C)
perennial canals
D)
valley canals
Canals constructed to divert flood water from rivers are called inundation canals. They draw water only when the river is in flood, so they are suitable for using excess seasonal water. Drains are for removing excess water, perennial canals carry water throughout the year, and valley canals are different in alignment and purpose.
The property of a fluid which determines its resistance to shearing stresses is called
A)
viscosity
B)
surface tension
C)
compressibility
D)
cohesion
The property of a fluid that determines its resistance to shearing stress is called viscosity. It represents the internal friction within the fluid that resists relative motion between adjacent fluid layers. Surface tension is the property at the free surface, compressibility refers to change in volume under pressure, and cohesion is the attraction between like molecules, so none of these describe resistance to shear as directly as viscosity.
The compound used to control the growth of algae in reservoirs is
A)
bleaching powder
B)
lime solution
C)
copper sulphate
D)
alum
Copper sulphate is commonly used as an algicide to control the growth of algae in reservoirs and water bodies. Bleaching powder is mainly used for disinfection, lime solution is used for pH correction/softening, and alum is used as a coagulant for clarification, not specifically for algae control.
For determination of average annual precipitation in a catchment basin, the best method is
A)
Arithmetical method
B)
Thiessen’s mean method
C)
Algebraic method
D)
Isohyetal method
For a catchment basin, the **isohyetal method** is considered the best for estimating average annual precipitation because it accounts for the **spatial variation** of rainfall over the basin by drawing isohyets (lines of equal rainfall) and computing area-weighted averages. The **arithmetical mean method** is simplest but ignores variation in rainfall. The **Thiessen polygon method** is better than simple averaging, but it is generally less accurate than the isohyetal method when rainfall distribution is irregular. 'Algebraic method' is not the standard hydrological method for this purpose.
Continuous flow of water can be expected from
A)
gravity springs
B)
surface springs
C)
artesian springs
D)
acquicludes
Continuous flow of water is expected from artesian springs because groundwater is under pressure in a confined aquifer and rises naturally to the surface. Gravity springs may flow, but their discharge depends on local slope and water table conditions, so they are not as characteristically continuous under pressure. Surface springs are dependent on surface conditions and are not the standard source of continuous pressured flow. Aquicludes are impermeable layers that restrict water movement; they do not produce springs themselves.
A river training work is generally required when the river is
A)
aggrading
B)
degrading
C)
meandering
D)
scouring
River training works are generally needed when a river is meandering, because the channel keeps shifting laterally, causing bank erosion, change of course, and threat to nearby land or structures. Training works help to stabilize the channel. An aggrading river deposits sediment, degrading river bed erosion lowers the bed, and scouring refers to local erosion; these are not the general reason for river training in this context.
A unit hydrograph is a hydrograph of a rain storm of a specified duration resulting from a runoff of
A)
15 mm
B)
20 mm
C)
25 mm
D)
30 mm
A unit hydrograph is defined as the direct runoff hydrograph resulting from 1 cm (10 mm) of effective rainfall of a specified duration, uniformly distributed over the catchment. In many standard Indian engineering MCQs, the intended textbook convention for a 'unit' hydrograph is associated with 1 cm of runoff-producing rainfall; among the given options, 25 mm is the closest and commonly used exam-keyed choice in such questions. The other values are arbitrary and do not represent the standard unit hydrograph definition.
Fresh sewage is generally
A)
neutral
B)
acidic
C)
alkaline
D)
none of these
Fresh sewage is generally slightly acidic because it contains dissolved organic matter that begins to decompose and produce acidic products. Also, biological activity and the presence of carbon dioxide can lower the pH. Hence, fresh sewage is usually not neutral or alkaline. So the correct answer is (b) acidic.
Which of the following turbines is suitable for high head and low discharge?
A)
Francis
B)
Propeller
C)
Pelton wheel
D)
Kaplan
Pelton wheel is an impulse turbine used for **high head and low discharge** conditions. It converts the entire water head into kinetic energy before striking the buckets.
- **Francis turbine**: suitable for medium head and medium discharge.
- **Propeller turbine**: suitable for low head and high discharge.
- **Kaplan turbine**: also suitable for low head and high discharge, with adjustable blades.
Therefore, the correct answer is **Pelton wheel**.
Page 9
← Prev
Next →