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  #2  
3rd December 2014, 04:15 PM
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Join Date: Apr 2013
Re: MAHAGENCO exam Question Papers

Here is the question paper for MAHAGENCO exam which you are looking for
MAHAGENCO exam Question Papers
1. A motor which can conveniently be operated at lagging as well as leading power factors is the
(A) squirrel cage induction motor.
(B) wound rotor induction motor.
(C) synchronous motor.
(D) DC shunt motor.
Ans: C
2. Space charge region around a p-n junction
(A) does not contain mobile carriers
(B) contains both free electrons and holes
(C) contains one type of mobile carriers depending on the level of doping of the p or n regions
(D) contains electrons only as free carriers
Ans: A
3. A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the
secondary. Assuming 100% efficiency, the primary current equals
(A) 0.2 Amp.
(B) 5 Amps.
(C) 10 Amps.
(D) 20 Amps.
Ans: A
EX: I1= V1 /R1 = 120/600 = 0.2 (ɳ = 100%, losses are zero therefore V1 = VR = I1R1)
4. A highly stable resonance characteristic is the property of a ____ oscillator.
(A) Hartley
(B) Colpitts
(C) Crystal
(D) Weinbridge
Ans. (C)
5. The speed-torque characteristics of a DC series motor are approximately similar to those of the
_________motor.
(A) universal
(B) synchronous
(C) DC shunt
(D) two-phase
Ans:A
6. In the heating process of the ________type a simple method of temperature control is possible
by means of a special alloy which loses its magnetic properties at a particular high temperature
and regains them when cooled to a temperature below this value.
(A) Indirect induction over
(B) core type induction furnace
(C) coreless induction furnace
(D) high frequency eddy current
Ans: D
7. The ________is a circuit-switched network, while the ______is a packet-switched network.
(A) Telephone, ATM
(B) SONET and FDDI
(C) Satellite, Telephone
(D) FDDI and SONET
Ans: (A)
8. Skewing in the slots of an induction motor is provided to reduce
(A) iron loss
(B) noise
(C) harmonics
(D) temperature rise.
Ans:C
9. The losses occurring in the rotor of an induction motor are less than those in the stator because
of
(A) small diameter of rotor
(B) less rotor frequency
(C) slot skewing
(D) none of the above
Ans:B
10. Which test is conducted on transformers to check its ability to withstand the transient
voltages due to lightening etc. ?
(A) Induced over voltage test
(B) Partial discharge test
(C) Impulse test
(D) Any of the above.
Ans:C
11. The output of a rotating electrical machine is limited by
(A) size of the machine
(B) peripheral velocity
(C) temperature rise
(D) none of the above.
Ans:C
12. A synchronous machine having large length of the air gap will have
(A) higher noise level
(B) smaller unbalanced magnetic pull
(C) lower limit of stability
(D) higher value of inherent regulation.
Ans:B
13. Bulk power transmission over long HVDC lines are preferred, on account of
(A)low cost of HVDC terminals
(B)no harmonic problems
(C)minimum line power losses
(D)simple protection
Ans:C
14. The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply.
The secondary output voltage will be
(A) 3.6 V.
(B) 2.5 V.
(C) 3.0 V.
(D) 6.0 V.
Ans: C
15. By using feedback in control systems, the sensitivity to parameter variation is improved.This
is achieved at the cost of
(A) stability
(B) loss of system gain
(C) transient response
(D) reliability
Ans: (B)
16. The fan-out of a MOS-logic gate is higher than that of TTL gates because of its
(A) low input impedance
(B) high output impedance
(C) low output impedance
(D) high input impedance
Ans: D
17. Divergence theorem is applicable for
(A) static field only
(B) time varying fields only
(C) both static and time varying fields
(D) electric fields only
Ans: C
18. A highly stable resonance characteristic is the property of a ____ oscillator.
(A) Hartley
(B) Colpitts
(C) Crystal
(D) Weinbridge
Ans. (C)
19. For a JFET, when VDS is increased beyond the pinch off voltage, the drain current
(A) Increases
(B) decreases
(C) remains constant.
(D) First decreases and then increases.
Ans. (C)
20. A radio frequency signal contains three frequency components, 870 KHz, 875 KHz and 880
KHz. The signal needs to be amplified. The amplifier used should be
(A) audio frequency amplifier
(B) wide band amplifier
(C) tuned voltage amplifier
(D) push-pull amplifier
Ans. (C)
EX:We need to amplify 3 signal frequencies i.e., 870 kHz, 875 kHz and 880 kHz. These
frequencies lie in a bandwidth of 10 kHz and we should use only tuned voltage amplifiers to
amplify them.
21. An oscillator of the LC type that has a split capacitor in the circuit is
(A) Hartley oscillator
(B) Colpitts oscillator
(C) Weinbridge oscillator
(D) R-C phase shift oscillator
Ans. (B)
22. In the voltage range, Vp < VDS < BVDSS of an ideal JFET or MOSFET
(A) The drain current varies linearly with VDS.
(B) The drain current is constant.
(C) The drain current varies nonlinearly with VDS.
(D) The drain current is cut off.
Ans: (B)
23. In a clamping circuit, the peak-to peak voltage of the waveform being clamped is
(A) affected by the clamping
(B) not affected by the clamping
(C) determined by the clamping voltage value
(D) determined by the ratio of rms voltage of the waveform and the clamping voltage
Ans: B
24. A ‘literal’ in Boolean Algebra means
(A) a variable inn its uncomplemented form only
(B) a variable ORed with its complement
(C) a variable in its complemented form only
(D) a variable in its complemented or uncomplemented form
Ans: D
25. A wave is incident normally on a good conductor. If the frequency of a plane electromagnetic
wave increases four times, the skin depth, will
(A) increase by a factor of 2.
(B) decrease by a factor of 4.
(C) remain the same.
(D) decrease by a factor of 2.
Ans: D
26. The frequency of the ripple in the output voltage of a 3-phase semiconverter depends upon
(A)firing angle and load resistance
(B)firing angle and supply frequency
(C)firing angle and load inductance
(D)only on load circuit parameters
Ans:B
27. A single phase diode bridge rectifier supplies a highly inductive load. The load current can be
assumed to be ripple free. The ac supply side current waveform will be
(A) sinusoidal
(B) constant dc.
(C) square
(D) triangular
Ans: C
28. The breakdown mechanism in a lightly doped p-n junction under reverse biased condition is
called
(A) avalanche breakdown.
(B) zener breakdown.
(C) breakdown by tunnelling.
(D) high voltage breakdown.
Ans: A
29. For a large values of |VDS|, a FET – behaves as
(A) Voltage controlled resistor.
(B) Current controlled current source.
(C) Voltage controlled current source.
(D) Current controlled resistor.
Ans: C
30. The minimum number of flip-flops required to construct a mod-75 counter is
(A) 5
(B) 6
(C) 7
(D) 8
Ans: C
Mahagenco Mechanical Engg questions with answers for practice, Mahagenco technical
questions and answers
1. What is the importance of the Thermodynamics in the field of Mechanical Engineering?
All the mechanical engineering systems are studied with the help of thermodynamics. Hence it is very
important for the mechanical engineers.
2. How many Laws of Thermodynamics are there?
There are three laws of the thermodynamics.
First Law: Energy can be neither created nor destroyed. It can only change forms.In any process in an
isolated system, the total energy remains the same.
Second Law: When two isolated systems in separate but nearby regions of space, each in thermodynamic
equilibrium in itself, but not in equilibrium with each other at first, are at some time allowed to interact,
breaking the isolation that separates the two systems, and they exchange matter or energy, they will
eventually reach a mutual thermodynamic equilibrium. The sum of the entropies of the initial, isolated
systems is less than or equal to the entropy of the final exchanging systems. In the process of reaching a
new thermodynamic equilibrium, entropy has increased, or at least has not decreased.
Third Law: As temperature approaches absolute zero, the entropy of a system approaches a minimum.
3. State Laws of conservation of energy?
According to the laws of conservation of energy, “energy can neither be created nor be destroyed. It can
only be transformed from one form to another.”
4. Is the boiler a closed system?
Yes definitely the boiler is a closed system.
5. What is Carnot engine?
It was being designed by Carnot and let me tell you that Carnot engine is an imaginary engine which
follows the Carnot cycle and provides 100% efficiency.
6. Which formula forms a link between the Thermodynamics and Electro chemistry?
Gibbs Helmholtz formula is the formula which forms the link between the thermodynamics and
electromagnetism.
∆Hs/R = [∂ lnp /∂ (1/T)]x
where: x – mole fraction of CO2 in the liquid phase
p – CO2 partial pressure (kPa)
T – temperature (K)
R – universal gas constant
α – mole ratio in the liquid phase (mole CO2 per mole of amine)
7. Which is the hardest compound known?
Diamond.
8. What is Hess Law?
According to the Hess law the energy transfer is simply independent of the path being followed. If the
reactant and the product of the whole process are the same then same amount of energy will be dissipated
or absorbed.
9. Which has more efficiency: Diesel engine or Petrol engines?
Off course Diesel engine has the better efficiency out of two.
10. A Bearing is designated as 6205 , what is it’s bore diameter?
Bore diameter is equal to : last two digit multiplied by 5.
In case of 6205 , the bore diameter =05 x 5 = 5 x 5 =25 mm
1.The third and fourth digits indicate the bore size in millimeters. Except for 0 through 3, the bore size is
simply five times the third and fourth digits together. 0 through 3, however, are different:
00 10mm
01 12mm
02 15mm
03 17mm
2.Bearing number starts from a number means it is a metric series bearing.
3.Type 6, “single-row deep groove”, is perhaps the most common type of bearing.
4.The second digit is the series reflects the robustness of the bearing.
In 6205 ….>second digit is 2 and it is a light series.
11. Advantages and Disadvantages of using LPG in car?
Advantages
1. Complete combustion
2. Fuel saving
3. Homogenous combustion
Disadvantages
1. As complete combustion is occurring ,more heat liberated,not advised for long journey, engine will be
over heated
2. Installation is difficult
3. Reduce engine life efficiency
12. All Reactor or Exchanger have Spherical/Hemispherical end Why?
Its in order to reduce the internal stress of the working substance.
For eg., If Water Vapour Dry is the working substance in the reactor or boiler and if the ends are square, at
the corners there are possibilities of pressure shoot up and also possibility of more pressure concentration
at those points. in order to avoid that, Spherical/Hemispherical Vessels are used. Spherical head is the only
remaining option because it is stronger.
One more place where Spherical vessels are used for storage is LPG Storage Containers
13. Compare Brayton and Otto cycle.
The heat addition and rejection processes in Otto cycle are of constant volume, whereas in Brayton cycle,
they are of constant pressure.
-Otto cycle is the ideal cycle for spark ignition engines.
-Brayton cycle is the ideal cycle for gas power turbines.
14. Current rating of a 3 phase DG set is 20 Amps, but what will be the per phase current for single phase
supply.
Amps means product of voltage and current. For 3 phase generator, its Amps = (1.732 X (Line Voltage) X
Current)/1000.
substitute the value and you get the answer.
15. Define Overall Heat transfer coefficient.
The overall heat transfer coefficient U is a measure of the overall ability of a series of conductive and
convective barriers to transfer heat. It is commonly applied to the calculation of heat transfer in heat
exchangers, but can be applied equally well to other problems.
1 / U A = 1 / h1 A1 + dxw / k A + 1 / h2 A2 (1)
where
U = the overall heat transfer coefficient (W/m2K)
A = the contact area for each fluid side (m2)
k = the thermal conductivity of the material (W/mK)
h = the individual convection heat transfer coefficient for each fluid (W/m2K)
dxw = the wall thickness (m)
The thermal conductivity – k - for some typical materials: .
Polypropylene PP – 0.12 W/mK
Stainless steel – 21 W/mK
Aluminum – 221 W/mK
16. Does Is 2062 Specifies Only Seamless Pipes Or ERW Pipe Is Also Covered Under Is 2062
IS:2062 Steel is a hot rolled structural steel that comes in three grades- low, medium and high tensile
strengths. So it’s only applied for Seamless pipe.
ERW (Electric Resistance Welding) pipe is manufactured by rolling metal and then welding it longitudinally
across its length. Seamless pipe is manufactured by extruding the metal to the desired length, hence ERW
pipe has a welded joint in its cross-section, while seamless pipe does not have any joint in its cross-section
through-out its length.
17. During Steam Blowing of Pipe Line, A Bluish Color Conical Pattern Is Observed At The End. Why?
Flames are blue because of the molecules that are produced during combustion. CH and C2 radicals give
off light in the green to blue region of the visible spectrum.
Fire needs oxygen to burn, and since the bottom of a flame does not get much oxygen, it is the hottest spot
in the flame and is blue in color.
18. Even though LPG is economical than petrol,why we are not promoting LPG usage?
Because it’s not an alternating source.
Its exhaust emissions contain a large number of harmful substances, these substances emitted to the
atmosphere, in a free state, ready for human and biological absorption affected by .
19 LPG does not have as many BTUs per gallon as petrol. That means an engine running on LPG will not
have as much power as the same engine running on petrol.
1. Pick up the wrong statement? A refrigent should have
a. Low specific heat of liquid
b. High boiling point
c. High latent heat of vaporization
d. Higher critical temperature
e. Low specific volume of vapour
Answer:
High boiling point
20. The property of a material which enable it to resist fracture due to high impact loads is known as
a. Elasticity
b. Endurance
c. Strength
d. Toughness
e. Resilience
Answer:Toughness
21. Spring index is
a. Ratio of coil diameter to wire diameter
b. Load required to produce unit deflection
c. Its capability of storing energy
d. Indication of quality of spring
e. Nothing
Answer:Ratio of coil diameter to wire diameter
22. Nodular iron has
a. High machinability
b. Low melting point
c. High tensile strength
d. Good fluidity
e. All of the above
Answer:All of the above
23 Six isometric views are given below along with 3 set of orthographic views. Please correlate the
orthographic views with their isometric view and write the answer in the box given below with a-f.
Answer:
D, A, B
1. The purpose of jigs and fixtures are to
a. Increased production rate
b. Increased machining accuracy
c. Facilitate interchangeable manufacturing
d. Enable employ less skilled operators
e. All of the above
Answer:All of the above
24. Which one of the following methods produces gear by generating process
a. Hobbing
b. Casting
c. Punching
d. Milling
e. Broaching
Answer:Hobbing
25 . Tool life of the cutting tool is most affected by
a. Cutting speed
b. Tool geometry
c. Cutting feed and depth
d. Microstructure of material being cut
e. Not using coolant and lubricant
Answer:Cutting speed
26 Metal in machining operation is removed by
a. Tearing chips
b. Distortion of metal
c. Shearing the metal across a zone
d. Cutting the metal across a zone
e. Pushing the metal with tool
Answer:Shearing the metal across a zone
27. A feeler gauge is used to check
a. Radius
b. Screw pitch
c. Surface roughness
d. Unsymmetrical shape
e. Thickness of clearance
Answer:Thickness of clearance
MAHAGENCO Mechanical Question Papers with Answers,MAHAGENCO Previous
Question Papers, MAHAGENCO Solved Question Papers
Technical Questions
1. A thermodynamic system is considered to be an isolated one if
(A) Mains transfer and entropy change are zero
(B) Entropy change and energy transfer are zero
(C) Energy transfer and mass transfer are zero
(D) Mass transfer and volume change are zero
Ans: (C)
2. A closed system is one in which
(A) Mass does not cross boundaries of the system, though energy may do so
(B) Mass crosses the boundary but not the energy
(C) Neither mass nor energy cross the boundary of the system
(D) Both energy and mass cross the boundaries of the system
Ans: (A)
3. Air is being forced by the bicycle pump into a tyre against a pressure of 4-5 bars. A slow downward
movement of the piston can be approximated as
(A) Isobaric process
(B) Adiabatic process
(C) Throttling process
(D) Isothermal process
Ans: (D)
4. Isentropic flow is
(A) Irreversible adiabatic flow
(B) Reversible adiabatic flow
(C) Ideal fluid flow
(D) Frictionless reversible flow
Ans: (B)
5. The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as
(A) Dual combustion cycle
(B) Diesel cycle
(C) Atkinson cycle
(D) Rankine cycle
Ans: (c)
6. Air injection is IC engine refers to injection of
(A) Air only
(B) Liquid fuel only
(C) liquid fuel and air
(D) Supercharging air
Ans: (b)
7. Turbo prop-engine has the following additional feature over the turbojet :
(A) Propeller
(B) Diffuser
(C) Starting engine
(D) Turbine and combustion chamber
Ans: (a)
8. In the SI engine, highest UBHC concentration is observed during
(A) Maximum load
(B) Acceleration
(C) Deceleration
(D) Idling
Ans: (d)
9. Shielding in a nuclear power plant is done
(A) To protect against neutron and gamma rays
(B) To absorb excess neutrons
(C) To slow down the speed of fast moving neutrons
(D) To return the neutrons back into the core of the reactor
Ans: (a)
10. In the film established along a vertical plate during condensation of any vapour over the plates, the
temperature distribution curve is
(A) Concave upwards
(B) Concave downwards
(C) Parabolic
(D) Straight line
Ans: (d)
11. In spite of large heat transfer coefficients in boiling liquids, cavities are used advantageously when
entire surface is exposed to
(A) Nucleate boiling
(B) Film boiling
(C) Transition boiling
(D) Pool boiling
Ans: (c)
12. What is the unit of dynamic viscosity of a fluid termed 'poise' equivalent to?
(A) dyne/cm2
(B) gm s/cm
(C) dyne s/cm2
(D) gm-cm/s
Ans:C
13. If the surface tension of water-air interface is 0.073 N/m, the gauge pressure inside a rain drop of 1 mm
diameter will be:
(A) 0.146N/m2
(B) 73N/m2
(C) 146N/m2
(D) 292 N/m2
Ans
Ex:P = 4σ/d = 4*0.073/.001 = 292N/m2
14. Which one of the following sets of conditions clearly apply to an ideal fluid?
(A) Viscous and compressible
(B) Non-viscous and incompressible
(c) Non-viscous and compressible
(d) Viscous and incompressible
Ans:B
15. Fluids that require a gradually increasing shear stress to maintain a constant strain rate are known as
(A) Rhedopectic fluids
(B) Thixotropic fluids
(C) Pseudoplastic fluids
(D) Newtonian fluids
Ans:A
16. At the interface of a liquid and gas at rest, the pressure is:
(A) Higher on the concave side compared to that on the convex side
(B) Higher on the convex side compared to that on the concave side
(C) Equal to both sides
(D) Equal to surface tension divided by radius of curvature on both sides
Ans:A
17. Willans line represents
(A) Total steam consumption vs power output with throttle governing
(B) Total steam consumption vs power output with cutoff governing
(C) Behaviour of supersaturated steam through nozzles
(D) Condensation of steam while flowing through the turbine
Ans: (A)
18. In a locomotive boiler, the draught is produced by
(A) Chimnay
(B) ID fan
(C) FD fan
(D) Steam jet
Ans: (D)
19. A Kaplan turbine is a
(A) Outward flow reaction turbine
(B) Inward flow impulse turbine
(C) Low head axial flow turbine
(D) High head mixed flow turbine
Ans: (C)
20. Navier – stokes equations are useful in the analysis of
(A) Turbulent flows
(B) Vortex flows
(C) Viscous flows
(D) Rotatioal flows
Ans: (C)
  #3  
23rd March 2015, 12:00 PM
Unregistered
Guest
 
Re: MAHAGENCO exam Question Papers

Can you provide me some Technical questions of MAHAGENCO or Maharashtra State Power Generation Company Limited as I will be giving the exam?
  #4  
23rd March 2015, 12:01 PM
Super Moderator
 
Join Date: Apr 2013
Re: MAHAGENCO exam Question Papers

Some Technical questions of MAHAGENCO or Maharashtra State Power Generation Company Limited as you will be giving the exam are as follows:

1. A thermodynamic system is considered to be an isolated one if

(A) Mains transfer and entropy change are zero
(B) Entropy change and energy transfer are zero
(C) Energy transfer and mass transfer are zero
(D) Mass transfer and volume change are zero
Ans: (C)

2. A closed system is one in which

(A) Mass does not cross boundaries of the system, though energy may do so
(B) Mass crosses the boundary but not the energy
(C) Neither mass nor energy cross the boundary of the system
(D) Both energy and mass cross the boundaries of the system

Ans: (A)

3. Air is being forced by the bicycle pump into a tyre against a pressure of 4-5 bars. A slow downward movement of the piston can be approximated as

(A) Isobaric process
(B) Adiabatic process
(C) Throttling process
(D) Isothermal process
Ans: (D)


4. Isentropic flow is

(A) Irreversible adiabatic flow
(B) Reversible adiabatic flow
(C) Ideal fluid flow
(D) Frictionless reversible flow
Ans: (B)

5. The cycle in which heat is supplied at constant volume and rejected at constant pressure is known as

(A) Dual combustion cycle
(B) Diesel cycle
(C) Atkinson cycle
(D) Rankine cycle
Ans: (c)

6. Air injection is IC engine refers to injection of

(A) Air only
(B) Liquid fuel only
(C) liquid fuel and air
(D) Supercharging air
Ans: (b)


7. Turbo prop-engine has the following additional feature over the turbojet :

(A) Propeller
(B) Diffuser
(C) Starting engine
(D) Turbine and combustion chamber
Ans: (a)

8. In the SI engine, highest UBHC concentration is observed during

(A) Maximum load
(B) Acceleration
(C) Deceleration
(D) Idling
Ans: (d)

9. Shielding in a nuclear power plant is done

(A) To protect against neutron and gamma rays
(B) To absorb excess neutrons
(C) To slow down the speed of fast moving neutrons
(D) To return the neutrons back into the core of the reactor
Ans: (a)


10. In the film established along a vertical plate during condensation of any vapour over the plates, the temperature distribution curve is

(A) Concave upwards
(B) Concave downwards
(C) Parabolic
(D) Straight line
Ans: (d)

11. In spite of large heat transfer coefficients in boiling liquids, cavities are used advantageously when entire surface is exposed to

(A) Nucleate boiling
(B) Film boiling
(C) Transition boiling
(D) Pool boiling
Ans: (c)


12. What is the unit of dynamic viscosity of a fluid termed 'poise' equivalent to?

(A) dyne/cm2
(B) gm s/cm
(C) dyne s/cm2
(D) gm-cm/s
Ans:C


13. If the surface tension of water-air interface is 0.073 N/m, the gauge pressure inside a rain drop of 1 mm diameter will be:

(A) 0.146N/m2
(B) 73N/m2
(C) 146N/m2
(D) 292 N/m2
Ans
Ex:P = 4σ/d = 4*0.073/.001 = 292N/m2

14. Which one of the following sets of conditions clearly apply to an ideal fluid?

(A) Viscous and compressible
(B) Non-viscous and incompressible
(c) Non-viscous and compressible
(d) Viscous and incompressible
Ans:B


15. Fluids that require a gradually increasing shear stress to maintain a constant strain rate are known as

(A) Rhedopectic fluids
(B) Thixotropic fluids
(C) Pseudoplastic fluids
(D) Newtonian fluids

Ans:A


16. At the interface of a liquid and gas at rest, the pressure is:

(A) Higher on the concave side compared to that on the convex side
(B) Higher on the convex side compared to that on the concave side
(C) Equal to both sides
(D) Equal to surface tension divided by radius of curvature on both sides
Ans:A


17. Willans line represents

(A) Total steam consumption vs power output with throttle governing
(B) Total steam consumption vs power output with cutoff governing
(C) Behaviour of supersaturated steam through nozzles
(D) Condensation of steam while flowing through the turbine
Ans: (A)

18. In a locomotive boiler, the draught is produced by

(A) Chimnay
(B) ID fan
(C) FD fan
(D) Steam jet
Ans: (D)


19. A Kaplan turbine is a

(A) Outward flow reaction turbine
(B) Inward flow impulse turbine
(C) Low head axial flow turbine
(D) High head mixed flow turbine
Ans: (C)


20. Navier – stokes equations are useful in the analysis of

(A) Turbulent flows
(B) Vortex flows
(C) Viscous flows
(D) Rotatioal flows
Ans: (C)


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