← MES Jr. Grade
Past Questions — 2015
The most promising method of disposal of radio active wastes seems to be
A)
Mixed with cement or other immobilizing agents
B)
Sealed in a steel drum for burial
C)
Vitrification
D)
Burial at great depth
Radioactive wastes are best disposed of by converting them into a stable glass-like solid through vitrification. This method immobilizes the radionuclides, greatly reduces the chance of leakage, and makes long-term storage safer. Mixing with cement or sealing in drums is less secure, and deep burial alone does not provide as reliable long-term containment as vitrification.
Mercury is used in barometers because
A)
Itis perfect fluid
B)
Its volume changes with temperature
C)
Itisaliquid metal
D)
It gives less height of column for high pressure
Mercury is used in barometers because it is very dense. For a given atmospheric pressure, a denser liquid requires a much shorter column height to balance the pressure. This makes the barometer compact and practical.
Why the others are incorrect:
- (a) Mercury is not used because it is a perfect fluid; no real fluid is perfect.
- (b) The change of volume with temperature is not the reason for its use.
- (c) Being a liquid metal is a property of mercury, but it is not the main reason for use in barometers.
Primary sewage treatment has traditionally implied
A)
Removal of bigger biodegradable substances
B)
Removal of suspended organic solids
C)
Removal of inorganic substances
D)
Removal of radioactive materials from others
Primary sewage treatment is the first physical treatment stage in which sewage is passed through screening, grit removal, and sedimentation. Its main purpose is to remove settleable and suspended solids, especially organic suspended matter. Hence, 'removal of suspended organic solids' is correct. Option (a) is too vague, (c) refers mainly to inorganic matter which is not the traditional definition of primary treatment, and (d) is unrelated.
The most common surface water supply source is
A)
Sea
B)
River
C)
Pond
D)
Lake
Surface water supply sources include rivers, lakes, ponds, and seas. Among these, rivers are the most common source used for water supply because they are widely available, provide large quantities of water, and are easier to tap compared to ponds and lakes. Sea water is not used directly for ordinary water supply due to high salinity.
Higher yield may be expected from
A)
Gravity spring
B)
Surface spring
C)
Artesian spring
D)
All ofthese
An artesian spring is formed when confined groundwater under pressure rises naturally to the surface. Because it is pressurized and fed by a confined aquifer, it generally provides a more reliable and higher discharge than gravity springs or surface springs. Gravity springs depend on local seepage and usually have smaller yield, while surface springs are more limited and less dependable. Hence, higher yield may be expected from an artesian spring.
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.
The pressure intensity in kg/cm² at any point ina liquid is
A)
w
B)
wh
C)
wh
D)
h/w
Pressure intensity at a depth h in a liquid is given by p = w h, where w is the specific weight of the liquid. This is the standard hydrostatic pressure formula. Option (d) h/w is incorrect because pressure increases with specific weight and depth, not inversely. Option (a) w is only specific weight, not pressure. Hence the correct choice is (c) wh.
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.
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.
Concentration of baron which will be harmful to most of the crop is
A)
More than 2 ppm
B)
More than 2.8 ppm
C)
More than 3 ppm
D)
More than 3.8 ppm
Boron is an essential micronutrient, but in irrigation water it becomes toxic to many crops when its concentration exceeds about 2 ppm. Hence, water with boron content more than 2 ppm is generally harmful to most crops. The higher values given in the other options are too high for the usual toxicity threshold.
Which of the following plays significant role for fluid to flow in laminar type?
A)
Pressure
B)
Temperature
C)
Viscosity
D)
Quantity
Laminar flow is the smooth, orderly flow of a fluid in layers. The property that strongly influences whether flow remains laminar is viscosity, because higher viscosity resists relative motion between fluid layers and helps maintain orderly flow. Pressure drives the flow, but it does not specifically determine the laminar nature. Temperature may affect viscosity indirectly, and quantity alone is not the controlling factor here.
In septic tank, decomposition of organic bacteria is done by
A)
Aerobic bacteria
B)
Anaerobic bacteria
C)
Both bacterias
D)
None of these
In a septic tank, sewage is stored in the absence of oxygen, so the decomposition of organic matter is mainly carried out by anaerobic bacteria. They break down the waste and produce gases like methane and carbon dioxide. Aerobic bacteria require oxygen, which is not available in sufficient amount inside a septic tank. Therefore, the correct answer is anaerobic bacteria.
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.
A multipurpose reservoir is the one which is
A)
Designed for one purpose but serves more than one purpose
B)
Planned and constructed to serve various purposes
C)
Both (a) and (b)
D)
None of these
A multipurpose reservoir is specifically designed from the beginning to fulfill more than one function, such as irrigation, flood control, hydropower generation, water supply, and recreation. Therefore, the correct definition is that it is planned and constructed to serve various purposes. Option (a) is not the standard definition because it suggests the reservoir was designed for one purpose and later serves others. Hence, (b) is correct and (c) cannot be correct because (a) is not accurate.
Gravel packing in underground water well
A)
Recharges the water level
B)
Reduces the percolation considerably
C)
Increases the specific capacity
D)
Reduces the effective diameter of well
Gravel packing around a well is used to improve the inflow of groundwater into the well by stabilizing the formation and reducing entrance losses. This increases the well’s yield per unit drawdown, i.e., its specific capacity. It does not recharge the water level, does not reduce percolation considerably, and it does not reduce the effective diameter of the well in a way that is the intended effect here.
Water supply system means
A)
Digging of well for water
B)
Construction of dams
C)
Construction of canals
D)
Entire arrangement from the source of supply to distribution
A water supply system includes all the components involved in providing water to users: source, collection, treatment, storage, transmission, and distribution. Therefore, the correct definition is the entire arrangement from the source of supply to distribution. Options (a), (b), and (c) mention only individual works, not the full system.
An aquifer that is confined at the bottom but not at the top is known as
A)
Partially confined aquifer
B)
Aquiclude
C)
Semi-confined aquifer
D)
Unconfined aquifer
An aquifer confined only at the bottom and open or only partly confined at the top is called a semi-confined aquifer, also known as a leaky aquifer. It receives some leakage through the upper confining layer. A partially confined aquifer is not the standard term here, an aquiclude is an impermeable confining layer, and an unconfined aquifer has no confining layer at the top.
The suitable layout of a distribution system for haphazardly developing city is
A)
Dead end system
B)
Gridiron system
C)
Ring system
D)
Radial system
For a haphazardly developing city, the **gridiron system** is the most suitable because it can serve irregular but expanding road patterns efficiently. It allows water to flow through multiple interconnected paths, giving better pressure distribution and reliability.
Why others are less suitable:
- **Dead end system**: Commonly used in old towns with irregular streets, but it has poor circulation and stagnation issues.
- **Ring system**: Best for planned areas where mains can be laid in loops around a locality.
- **Radial system**: Suitable for well-planned cities with a central distribution point.
Hence, the correct answer is **(b) Gridiron system**.
Gauge pressure is the same as
A)
Atmospheric pressure - absolute pressure
B)
Atmospheric pressure - vacuum
C)
Absolute pressure - atmospheric pressure
D)
Absolute pressure + atmospheric pressure
Gauge pressure is defined as the pressure measured relative to atmospheric pressure. Therefore,
Gauge pressure = Absolute pressure - Atmospheric pressure.
So option (c) is correct. Option (a) is incorrect because it reverses the terms. Option (b) is incorrect because vacuum pressure is not the same as atmospheric pressure minus vacuum in this context. Option (d) is incorrect because absolute pressure is not added to atmospheric pressure.
The maximum pressure to which a pipe is subjected during its operation is known as
A)
Working pressure
B)
Design pressure
C)
Pipe pressure
D)
Test pressure
The maximum pressure a pipe experiences under normal operating conditions is called the working pressure. Design pressure is the pressure used for selecting pipe thickness and safety margins, and test pressure is the higher pressure used during pressure testing before commissioning. 'Pipe pressure' is not the standard technical term here.
The difference of the top ofa bank and the full supply level in a canal is called
A)
Berm
B)
Free board
C)
Height of bank
D)
None of these
In canal engineering, the vertical difference between the top of the canal bank and the full supply level (FSL) is called the free board. It provides safety against overtopping due to waves, surges, or operational fluctuations. A berm is a horizontal strip of land left between two slopes or between a bank and excavation, and height of bank refers to the overall height of the bank, not specifically the difference from FSL to top of bank.
The most suitable material for house sewer is
A)
Bituminized fibre
B)
Ductileiron
C)
Corrugated metal
D)
Solid wall plastic
House sewers are best made of materials that are smooth, corrosion-resistant, light, and easy to install. Solid wall plastic pipes satisfy these requirements well, so they are considered the most suitable material for house sewer. Bituminized fibre is less durable, ductile iron is costlier and more commonly used for pressure lines, and corrugated metal is not suitable because it is prone to corrosion and roughness.
The losses in canal are usually measured by a simple method known as
A)
Absorption
B)
Inflow and outflow
C)
Percolation
D)
Shallow pumping
Canal losses are commonly measured by the **inflow and outflow method**, where discharge entering a canal reach is compared with the discharge leaving it. The difference gives the loss due to seepage, evaporation, and other causes.
- **(a) Absorption**: not a standard method of measuring canal losses.
- **(c) Percolation**: this is one type of loss, not a measuring method.
- **(d) Shallow pumping**: unrelated to canal loss measurement.
Therefore, the correct answer is **inflow and outflow**.
An ideal fluid is
A)
One which obeys Newton’s law of viscosity
B)
One which satisfies continuity equation
C)
One-which flows through pipes with least friction
D)
Frictionless and incompressible
An ideal fluid is a hypothetical fluid assumed to have no viscosity (frictionless) and to be incompressible.
- (a) is wrong because a fluid obeying Newton’s law of viscosity is a real viscous fluid, not ideal.
- (b) is wrong because continuity equation applies to fluid flow in general; it does not define an ideal fluid.
- (c) is wrong because “least friction” is not the standard definition.
- (d) is correct because ideal fluid is defined as frictionless and incompressible.
As a general rule, new sewer systems must be designed
A)
To combine sanitary and storm flows
B)
To separate sanitary and storm flows
C)
To care for storm water first and then sanitary sewage
D)
To treat storm sewage contamination
As a general rule, new sewer systems are designed as separate systems so that sanitary sewage and storm water are carried independently. This prevents overloading of treatment plants during rainfall and reduces the size and cost of sewage treatment. Combined sewers are generally avoided in new designs. Hence, option (b) is correct. Options (a), (c), and (d) do not state the standard design principle for new sewer systems.