← MES Jr. Grade
Past Questions — 2015
Bernoulli’s equation assumes that
A)
Fluidis non-viscous
B)
Fluid is homogeneous
C)
Flowis steady
D)
All ofthese
Bernoulli’s equation is derived under ideal flow assumptions. It assumes the fluid is non-viscous, the flow is steady, and the fluid is homogeneous (incompressible for most civil engineering applications). Since all the listed conditions are part of the Bernoulli assumptions, the correct answer is 'All of these'. Options (a), (b), and (c) are each true individually, so they are not the best single answer.
The most suitable section of a lined canal is
A)
Triangular section with circular bottom for small canals
B)
Trapezoidal section with rounded corners for large canals
C)
Rectangular section with rounded corners for large canals
D)
Both (a) and (b)
A lined canal is usually designed to have the most economical hydraulic section, good flow efficiency, and ease of construction. For large canals, a trapezoidal section with rounded corners is considered most suitable because it provides stable side slopes, good hydraulic performance, and reduces seepage and stress concentration at corners. Rectangular sections are generally less economical for open canals, and triangular sections are mainly used only for very small drains or channels, not as the most suitable general lined canal section. Hence, option (b) is correct.
Which of the following phenomenon in a pipe flow is termed as water hammer ?
A)
The sudden rise of pressure in a long pipe due to sudden closure of valve
B)
The rise of a pressure in a pipe flow due to gradual closure of a valve
C)
The rise of negative pressure
D)
The zero pressure in a pipe flow
Water hammer is the pressure surge (or shock wave) created when a moving fluid in a pipe is suddenly forced to stop or change direction, typically by rapid valve closure. This causes a sudden rise in pressure in the pipe. Option (b) is incorrect because gradual closure produces a much smaller pressure change. Options (c) and (d) do not describe water hammer.
In order to prevent settlement of the sewage solid in sanitary sewers, velocity required to be maintained is not less than ;
A)
0.4m/s
B)
0.6m/s
C)
0.75 m/s
D)
0.8m/s
In sanitary sewer design, a minimum self-cleansing velocity is maintained so that suspended sewage solids do not settle and cause choking. The commonly accepted minimum velocity is about 0.6 m/s. Hence, among the given options, 0.6 m/s is correct. The lower values 0.4 m/s and 0.75 m/s are not the standard minimum threshold used for preventing deposition, and 0.8 m/s is higher than necessary for the stated purpose.
A piezometer opening in pipe measures
A)
Velocity head
B)
Static pressure
C)
Total pressure
D)
Double static pressure
A piezometer is a simple vertical tube connected to a pipe. The liquid rises in it until the hydrostatic head balances the pressure at the tapping point, so it measures the **static pressure head** (pressure intensity) in the pipe. It does not measure velocity head or total pressure. Total pressure would require a stagnation device like a Pitot tube.
Raw water treated with only chlorine is known as :
A)
Plain chlorination
B)
First chlorination
C)
Pre-chlorination
D)
De-chlorination
Raw water that is treated with chlorine before any other treatment steps is called pre-chlorination. It is commonly done at the intake or before sedimentation to control algae, reduce taste and odor, and help in purification.
Why others are incorrect:
- Plain chlorination: not the standard term for chlorinating raw water at the initial stage.
- First chlorination: not the usual technical term used in water treatment.
- De-chlorination: means removal of chlorine, the opposite of adding chlorine.
Hydrostatic pressure on a dam depends upon its :
A)
Length
B)
Depth
C)
Shape
D)
Material
Hydrostatic pressure in a fluid at rest is given by p = ρgh, where h is the depth below the free surface. Therefore, the pressure on a dam increases with depth. It does not depend on the dam’s length, shape, or material for the pressure itself—though the total force on the dam depends on the area and distribution of pressure.
Intensity of rainfall is
A)
Total rainfall ina period
B)
Rainfall per unit area
C)
Volume of water collected per unit time
D)
Depth of rainfall per unit time during which it fell
Rainfall intensity is defined as the rate of rainfall, i.e., the depth of rain falling in a given unit time, usually expressed in mm/h. Option (d) matches this definition exactly. Option (a) is total rainfall over a period, not intensity. Option (b) refers to rainfall amount over an area, and option (c) is not the standard definition of rainfall intensity.
The difference between the total rainfall and that which is intercepted is called
A)
Rainfall interception
B)
Residual rain
C)
Net rainfall
D)
Ground rainfall
Interception is the portion of rainfall caught by vegetation, roofs, etc., and does not reach the ground. The rainfall remaining after subtracting interception from total rainfall is called net rainfall.
So:
- Total rainfall - intercepted rainfall = net rainfall
- Option (a) is the process itself, not the remainder.
- Option (b) is not the standard hydrology term here.
- Option (d) ground rainfall is not the accepted term for this definition.
The retention time of septic tank at average daily flow is
A)
8 hours
B)
12 hours
C)
24 hours
D)
48 hours
The detention or retention time of a septic tank at average daily flow is generally taken as about 24 to 48 hours, and in standard exam practice the commonly accepted design value is 48 hours. This allows sufficient settling of solids and anaerobic digestion. 8 hours and 12 hours are too short for proper settling, while 24 hours is often considered the minimum range but not the usual exam answer for septic tank retention time.
For providing an Indian type W.C, the RCC slabs in the toilet portion
A)
Should be sunk by 20 cm
B)
Should be sunk by 50 cm
C)
Should be kept 20 cm above the adjacent portion
D)
Need not be sunk
In an Indian type W.C., the toilet floor/slab portion is generally sunk below the adjacent floor level to accommodate the pan and ensure proper laying of pipes and waterproofing. The standard depth used in such exam questions is about 20 cm. Hence, option (a) is correct. The other options are incorrect because 50 cm is excessively deep, keeping it above the adjacent floor is the opposite of the required arrangement, and it cannot be left without sinking for an Indian type W.C.
In normal conditions, the period for sludge digestion is
A)
10 days
B)
20 days
C)
30 days
D)
60 days
In conventional sewage treatment, sludge digestion under normal conditions typically takes about 30 days. This is the standard detention period used in digestion tanks for proper stabilization of sludge. 10 days and 20 days are generally too short for normal digestion, while 60 days is longer than the usual normal-condition period.
In hydraulic jump, passage of water is
A)
Froma super critical state to sub-critical state
B)
From sub-critical state to super critical state
C)
From critical state to super critical state
D)
From sub-critical state to critical state
A hydraulic jump occurs when fast-moving shallow water (supercritical flow, Froude number > 1) suddenly transitions to slower-moving deeper water (subcritical flow, Froude number < 1). This causes a rapid rise in water depth and dissipation of energy. Hence, the passage of water is from supercritical state to subcritical state. The other options describe the reverse or incorrect transitions.
Which of the following is the standard treatment of rapid sand filter plants?
A)
Plain chlorination
B)
Pre chlorination
C)
Post chlorination
D)
Super chlorination
Rapid sand filters are commonly preceded by chlorination to control algae, reduce taste and odor, and aid coagulation and filtration performance. This is called pre-chlorination. Plain chlorination is not a specific treatment stage, post-chlorination is done after filtration and disinfection, and super-chlorination is an excessive dose used only in special conditions, not as the standard treatment of rapid sand filter plants.
Cross regulators in main canals are provided
A)
To regulate water supply in the distributaries
B)
To increase water head upstream when a main canal is running with low supply
C)
To overflow excessive flood water
D)
None of these
A cross regulator is constructed across a main canal to control the water level in the canal. When the canal is carrying a low supply, it helps raise and maintain the upstream water head so that water can still be diverted into off-taking channels and distributaries. Option (a) is the function of distributary head regulators, not cross regulators. Option (c) describes a spillway or waste weir, not a cross regulator.
The frictional resistance in the laminar flow is
A)
Not affected by the variation of temperature
B)
Dependant of pressure
C)
Proportional to the velocity of flow
D)
All ofthese
In laminar flow, the resisting shear stress is directly proportional to the velocity gradient, and for flow through a pipe the frictional resistance is proportional to the flow velocity. It is not generally stated as being dependent on pressure, and temperature affects viscosity, so option (a) is incorrect. Hence, the correct choice is (c).
The most widely used tube well in India is
A)
Strainer well
B)
Cavity well
C)
Slotted well
D)
Perforated well
The most widely used tube well in India is the strainer well. It is suitable for aquifers with sand and gravel and is commonly adopted because it is effective and economical. Cavity wells are used only in certain hard strata conditions, while slotted and perforated wells are less common as standard tube well types.
The minimum diameter of an opening of a manhole should be
A)
50cm
B)
100cm
C)
25cm
D)
150 cm
A manhole opening must be large enough for a person to enter, inspect, and maintain the sewer safely. The standard minimum diameter of a manhole opening is 100 cm (1 m). Smaller options like 25 cm or 50 cm are too small for human access, while 150 cm is larger than the minimum requirement.
Balancing depth in irrigation canal section is
A)
Depth in which flow of water is optimum
B)
Depth in which cutting and filling will be equal
C)
Depth in which required side slope will be maintained
D)
Depth in which length of canal will be minimum
Balancing depth in a canal section is the depth at which the earthwork in excavation (cutting) equals the earthwork in embankment (filling). This makes the canal section economically balanced, with no surplus cut or fill. Option (a) refers to an optimum hydraulic depth, option (c) is about side slope design, and option (d) is unrelated to the definition of balancing depth.
If the pressure surface of Aquifer lies above the ground surface, the well will be
A)
Artesian well
B)
Non-artesian well
C)
Flowing artesian well
D)
Non-flowing artesian well
When the pressure surface (piezometric surface) of a confined aquifer lies above the ground surface, water rises in the well and overflows naturally at the surface. Such a well is called a flowing artesian well. An artesian well may have water rise in it, but if the pressure surface is below ground level, it will not flow out naturally. Non-artesian wells are ordinary wells without confined aquifer pressure.
The distribution mains in water supply system are designed for
A)
Maximum daily demand
B)
Peak hourly demand
C)
Average daily demand
D)
Maximum hourly demand on maximum consumption day
Distribution mains in a water supply system must carry the highest likely flow in the distribution network. Therefore, they are designed for the maximum hourly demand occurring on the maximum consumption day, since this represents the peak stress condition.
Why not the others?
- (a) Maximum daily demand: too low for design of mains.
- (b) Peak hourly demand: does not specify the worst day, so it is incomplete.
- (c) Average daily demand: far below actual design requirement.
Hence, the correct answer is maximum hourly demand on maximum consumption day.
Which of the following fluids can be classified as non-Newtonian?
A)
Kerosene oil
B)
Diesel oil
C)
Human blood
D)
Toothpaste
Non-Newtonian fluids do not have a constant viscosity and their flow behavior changes with applied stress. Among the options, toothpaste is a classic non-Newtonian fluid because it behaves like a solid until sufficient force is applied, then it flows. Kerosene oil and diesel oil are Newtonian fluids, and human blood is also commonly classified as a non-Newtonian fluid, but in standard exam MCQs with a single expected answer, toothpaste is the best choice here.
The best coagulant for removing the colour of water is
A)
Alum
B)
Lime
C)
Iron sulphate
D)
Copper sulphate
Alum is the most commonly used coagulant for water treatment and is especially effective in removing turbidity and colour by destabilizing colloidal particles. It forms flocs of aluminium hydroxide that adsorb coloured organic matter and impurities. Lime is mainly used for softening and pH adjustment, iron sulphate is also a coagulant but is less commonly preferred for colour removal in standard water treatment, and copper sulphate is not used as a coagulant for this purpose.
The intensity-duration-frequency curves for precipitation indicate
A)
that the greater the intensity of rainfall the shorter length of time it continues
B)
the days on which rainfall occurs at a location
C)
that cumulative rainfall over a period with frequency of periodic peaks is ultimately constant
D)
thatthe intensity of rainfall increases as the duration increases
Intensity-duration-frequency (IDF) curves show the relationship among rainfall intensity, storm duration, and return period. In general, for a given frequency, shorter-duration storms have higher rainfall intensity, while longer-duration storms have lower intensity. Therefore, the correct statement is that the greater the intensity of rainfall, the shorter the length of time it continues. Option (d) is the opposite of this relationship, and (b) and (c) do not describe IDF curves.
Any independent mass of fluid does not possess
A)
Elevation energy
B)
Kinetic energy
C)
Pressure energy
D)
None of these
An independent mass of fluid can possess elevation energy and kinetic energy. However, pressure energy is not associated with a fluid mass by itself in the same way; it is generally considered in a flowing fluid system as energy due to pressure. Hence, the correct answer is pressure energy.