← MES Jr. Grade
Past Questions — 2015
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**.
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.
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.
Surface water should never be used before treatment because it _
A)
Contains large amount of impurities
B)
Is contaminated by impurities while travelling
C)
Contains disease producing bacteria
D)
Allofthese
Surface water is generally not safe for direct use because it usually contains a large amount of impurities, gets contaminated while flowing over land, and often carries disease-producing bacteria. Since all three statements are true, the correct answer is 'All of these'.
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.
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 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.
A time-intensity graph of a rain storm is assumed to be made up of
A)
Straight line
B)
Curves
C)
Irregular shaped line
D)
Mixture of straight line and curves
A time-intensity graph (hyetograph) of a rain storm is generally represented by a combination of straight lines and curves, depending on how rainfall intensity varies with time. It is not usually assumed to be only straight lines, only curves, or an irregular shape alone. Hence, the correct choice is a mixture of straight line and curves.
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.
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 change of physical property in isothermal process is governed by
A)
Reynold’s number
B)
Bernoulli’s equation
C)
Boyle’s Law
D)
Navier-Stokes equation
In an isothermal process, temperature remains constant. For a gas undergoing isothermal compression or expansion, pressure and volume vary inversely, so the change in physical property is governed by Boyle’s Law (P1V1 = P2V2). Reynold’s number relates to flow regime, Bernoulli’s equation relates pressure-velocity-energy in fluid flow, and Navier-Stokes equations describe fluid motion, not the isothermal gas law.
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.
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.
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.
Hydraulic ram is a device used
A)
To lift water without electric motor
B)
To accelerate water flow
C)
For lifting heavy load
D)
None of these
A hydraulic ram is a pump that uses the kinetic energy of flowing water to lift a portion of that water to a higher level without requiring any external power source like an electric motor. Hence, option (a) is correct. Option (b) is incorrect because it does not accelerate water flow; it converts flow energy into pumping action. Option (c) is unrelated, as it is not used for lifting heavy loads.
The continuity equation of fluid flow is the mathematical statement of
A)
The Principle of Conservation of Mass
B)
The Principle of Conservation of Energy
C)
The Principle of Conservation of Momentum
D)
The Principle of Conservation of Impulse Momentum
The continuity equation in fluid mechanics expresses that mass cannot be created or destroyed in a flow. For a control volume, the rate of mass entering equals the rate of mass leaving plus the rate of accumulation. Hence, it is the mathematical form of the Principle of Conservation of Mass. The other options relate to different governing equations: energy conservation gives Bernoulli/energy equation, and momentum conservation gives the momentum equation, not continuity.
The dominant mode in a waveguide is characterized by __
A)
longest cutoff λ
B)
shortest cutoff λ
C)
infinite attenuation
D)
zero attenuation
In a waveguide, the dominant mode is the mode with the lowest cutoff frequency, which is equivalent to the longest cutoff wavelength. For a rectangular waveguide, this is typically the TE10 mode. Option (b) is the opposite of the definition, while (c) and (d) are not characteristics used to define the dominant mode.
Which power amplifier can deliver maximum load power?
A)
Class A
B)
Class AB
C)
Class B
D)
Class C
A Class B power amplifier has the highest theoretical efficiency among the given classes, with a maximum efficiency of about 78.5%. Because it wastes less power as heat than Class A or Class AB, it can deliver the maximum load power for a given supply. Class A has the lowest efficiency, Class AB is between A and B, and Class C is highly efficient but is used mainly for tuned RF applications, not for maximum linear load power delivery.
Nichols chart consists of
A)
Constant magnitude loci
B)
Constant phase angle loci
C)
Magnitude and phase angle loci in log magnitude versus phase diagram
D)
None of these
A Nichols chart is a frequency-response plot with gain (magnitude in dB) on one axis and phase angle on the other. It shows constant closed-loop magnitude and phase contours on a log-magnitude versus phase diagram. Hence, option (c) is correct. Options (a) and (b) describe only one type of locus each, not the Nichols chart as a whole.
Coulomb’s Law is a
A)
vector equation
B)
scalar equation
C)
may be (a) or (b)
D)
phasor equation
Coulomb’s law gives the electrostatic force between two charges. The force has both magnitude and direction, so it is expressed as a vector equation. The scalar form gives only the magnitude, but the law itself is fundamentally vector in nature. Hence, (a) is correct. Options (b), (c), and (d) are incorrect because Coulomb’s law is not merely scalar, not both arbitrarily, and not a phasor equation.
An oscillator requires an amplifier
A)
with negative feedback
B)
with positive feedback
C)
with either positive or negative feedback
D)
none of these
An oscillator needs regenerative or positive feedback so that a portion of the output is fed back in phase with the input, sustaining continuous oscillations. Negative feedback would oppose the signal and suppress oscillations. Therefore, the correct choice is (b).
If the poles of a system lie on the imaginary axis, the system will be
A)
stable
B)
conditionally stable
C)
marginally stable
D)
unstable
In control systems, if the poles lie exactly on the imaginary axis, the system neither decays nor grows with time. Such a system is called marginally stable. It is not asymptotically stable because the response does not die out, and it is not unstable unless there are poles in the right half-plane. Hence, the correct answer is marginally stable.
According to maximum power transfer theorem, if the load is inductive, the source should be
A)
Inductive
B)
Capacitive
C)
Resistive
D)
All of the above
For maximum power transfer in AC circuits, the load impedance must be the complex conjugate of the source (Thevenin) impedance. If the load is inductive, its reactance is positive, so the source should have equal and opposite reactance, i.e., capacitive. This cancels the reactive part and allows maximum real power transfer. Hence, the correct option is capacitive.
In a bridge rectifier circuit the rms value of input ac voltage is 10V. The PIV across each diode is
A)
7.07V
B)
14.14V
C)
10V
D)
28.28V
For a bridge rectifier, the peak inverse voltage (PIV) across each diode is equal to the peak value of the input AC voltage. Given rms input voltage Vrms = 10 V, the peak value is Vm = Vrms × √2 = 10 × 1.414 = 14.14 V. Hence, PIV across each diode is 14.14 V. Option (a) is the rms-to-peak conversion of 5 V, not applicable here; (c) is the rms value itself; and (d) is twice the peak value, which is not the PIV for a bridge rectifier.
An OPAMP has a slew rate of 5 V/ μS. The largest sine wave O/P voltage possible at a frequency of 1MHZ is
A)
10volts
B)
5 volts
C)
15volts
D)
5/2 volts
For a sine wave, the maximum slope is at the zero crossing and equals 2πfVmax. This must not exceed the slew rate.
Given:
Slew rate = 5 V/μs = 5 × 10^6 V/s
Frequency f = 1 MHz = 10^6 Hz
So,
2πfVmax ≤ SR
Vmax ≤ SR / (2πf)
Vmax ≤ (5 × 10^6) / (2π × 10^6) = 5 / (2π) ≈ 0.8 V (peak)
But the options are in terms of output voltage, and in many exam contexts this is taken as peak-to-peak value:
Vpp = 2Vmax ≈ 1.6 V, which still does not match the options.
However, the standard MCQ formula often used is:
Vmax = SR / (2f) = 5 / (2 × 1) = 2.5 V
which corresponds to option (d) 5/2 volts.
So the expected exam answer is (d).