← MES Jr. Grade
Past Questions
A river training works required is generally required when the river is
A)
Meandering
B)
Aggrading
C)
Degrading
D)
Allofthese
River training works are generally required in all three cases:
1. Meandering rivers shift their course and cause bank erosion, so training works are needed to stabilize the channel.
2. Aggrading rivers deposit silt and raise the riverbed, affecting flow and increasing flood risk.
3. Degrading rivers scour their bed and may undermine structures and banks.
Since river training is needed for meandering, aggrading, and degrading rivers, the correct option is 'All of these'.
For centrifugal pumps
A)
Limited space is required
B)
Initial cost is low
C)
Steady discharge is obtained
D)
Allofthese
Centrifugal pumps have several advantages: they require relatively limited space, their initial cost is generally low compared to many other pumps, and they provide a steady and continuous discharge. Therefore, all the given statements are correct.
Rainfall records are maintained on
A)
Daily basis
B)
Monthly basis
C)
Yearly basis
D)
None of these
Rainfall is generally recorded by rain gauges as a daily observation, because rainfall can vary significantly from day to day and hydrological analysis needs day-wise data. Monthly and yearly values are usually computed later by summing the daily records. Therefore, the correct answer is Daily basis.
If Mach Number is slightly less than or slightly greater than 1, then the flow is termed as
A)
Sonic
B)
Hypersonic
C)
Transonic
D)
Supersonic
Mach number near 1 means the flow speed is close to the speed of sound. When the Mach number is slightly less than 1 or slightly greater than 1, the flow is called transonic. Sonic means exactly Mach 1, supersonic means greater than 1, and hypersonic refers to very high Mach numbers (typically above 5).
Sewage sickness in land disposal means
A)
When the disposal site is full
B)
When the over burden load exceeds the bearing capacity of soil at disposal site
C)
When aerobic condition can no longer continue and anaerobic condition starts
D)
When pathogens start to grow due to lack of treatment
Sewage sickness in land disposal occurs when the soil is overloaded with sewage beyond its capacity to absorb, treat, and percolate it. This excessive hydraulic/organic loading clogs the soil pores and the disposal area fails to function properly. Option (b) states this correctly. Option (a) is incorrect because it is not about the site being physically full, and option (c) describes a general shift to anaerobic conditions, not the definition of sewage sickness. Option (d) is also incorrect because pathogen growth is not the defining meaning of sewage sickness.
Irrigation canals are generally aligned along
A)
Ridgeline
B)
Contour line
C)
Valley line
D)
Straight line
Irrigation canals are generally aligned along the contour line so that water can be distributed by gravity with minimum cutting and filling. A contour alignment helps maintain a nearly uniform water level along the canal. Ridgeline is not suitable for canal alignment, valley line is usually the natural drainage path and not preferred for main canals, and a straight line is not the governing criterion in canal alignment.
Trickling filter in treating domestic and industrial waste use
A)
Physico-chemical treatment
B)
Biological treatment
C)
Chemical treatment
D)
Combination of biological and chemical treatment
A trickling filter is an attached-growth **biological treatment** process used in wastewater treatment. Wastewater is sprayed over a bed of media, and microorganisms growing on the media oxidize the organic matter. It is not primarily a physico-chemical or chemical process. Hence, option (b) is correct. Options (a), (c), and (d) are incorrect because the main mechanism is biological decomposition by microbes.
The structure constructed to allow drainage water to flow under pressure through an inverted syphon below a canal is .
A)
Syphon
B)
Aqueduct
C)
Super passage
D)
Syphon-aqueduct
An inverted siphon carrying drainage water under a canal under pressure is called a syphon-aqueduct. In this arrangement, the canal is carried over the drain in a trough, while the drain flows below through a pressure conduit. By contrast: (a) Syphon alone usually refers to the pressure flow structure, but the standard irrigation cross-drainage structure described here is the combined form, syphon-aqueduct. (b) Aqueduct means the canal is carried over the drain with the drain flowing freely below, not under pressure. (c) Super passage is the opposite case, where the drain is carried over the canal. Therefore, the correct answer is syphon-aqueduct.
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.
Based on Silt theories for design of bed slope of irrigation canal
A)
The natural slope is much flatter than designed bed slope
B)
The natural slope and designed bed slop
According to silt theories used in canal design, the bed slope of an irrigation canal is chosen by comparing the canal’s designed slope with the natural ground slope. In the usual case, the natural slope is much flatter than the designed bed slope, so the canal must be aligned and graded to maintain the required flow velocity and avoid silting or scouring. Hence option (a) is correct.
Option (b) is incorrect because the natural slope and the designed bed slope are generally not the same; canal design typically requires a slope different from the natural ground slope to achieve stable hydraulic conditions.
The infiltration capacity is
A)
Maximum rate of accumulation of water in an area
B)
(Precipitation - evaporation loss) per unit time
C)
Maximum rate at which water enters the soil
D)
Rainfall water entering sub-soil
In hydrology, infiltration capacity is defined as the maximum rate at which a soil can absorb water at a given time under specific conditions. It refers to the upper limit of water entry into the soil surface. Option (a) describes water accumulation, not infiltration. Option (b) is unrelated to the definition of infiltration capacity. Option (d) is too general and refers to percolation into sub-soil rather than infiltration at the ground surface.
During epidemics the best and economic method of disinfection of water treatment is
A)
By potassium permanganate
B)
Byozone
C)
By boiling water
D)
By chlorination
During epidemics, water must be disinfected effectively, cheaply, and at a large scale. Chlorination is the standard and most economical method used in water treatment because it is practical for continuous supply and leaves a residual disinfectant effect. Potassium permanganate is not a reliable disinfectant for drinking water, ozone is effective but expensive and not economical for routine epidemic use, and boiling is effective for small quantities but not suitable for large-scale water treatment.
Disinfection of drinking water isdonetoremove _
A)
Colour
B)
Turbidity
C)
Bacterias
D)
Acidity
Disinfection of drinking water is done to destroy or remove disease-causing microorganisms, especially bacteria. Colour and turbidity are removed by treatment processes like coagulation, sedimentation, and filtration, while acidity is corrected by neutralization or pH adjustment. Hence, the correct answer is bacteria.
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.
The fundamental equation forthe computation ofrun off is
A)
Precipitation + basin recharge — ground water accretion
B)
Precipitation— basin recharge + ground water accretion
C)
Precipitation — basin recharge — ground water accretion
D)
Precipitation + basin recharge + ground water accretion
Runoff is the portion of precipitation that remains after losses such as basin recharge (infiltration/percolation) and groundwater accretion/storage. Hence, the fundamental runoff equation is:
Runoff = Precipitation − Basin recharge − Ground water accretion.
Option (c) matches this relationship. The other options incorrectly add the loss terms instead of subtracting them.
The ratio between inertia force and viscous force is called
A)
Reynold’s number
B)
Froude’s number
C)
Weber’s number
D)
Euler’snumber
The ratio of inertia force to viscous force in fluid flow is defined as the Reynolds number. It indicates whether the flow is laminar or turbulent. Froude number compares inertia force to gravitational force, Weber number compares inertia force to surface tension force, and Euler number compares pressure force to inertia force.
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 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.
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.
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**.
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.
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.
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.
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.
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.