HAL Placement-Paper on Oct 30, 2013

Discussion in 'Latest Placement papers' started by krishna, Nov 14, 2013.

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    HAL EIL,GAIL,BHEL Upcoming examinations model questions for learn and practice Current affairs of business Questions 2013 Nobel Prize winners of different categories



    RBI New Governor-Dr. Raghuram Rajan



    RBI Allowed Banks to Revise Periodicity of Interest Payments

    Reserve Bank of India Increased the Repo Rate by 25 Basis Points to 7.75 %from 7.50%

    India's Foreign Exchange Reserves jumped to 281.12 Billion US Dollars

    Miss World 2013
    Megan Young of Philippines on 28 September 2013 was crowned Miss World 2013

    2020 Olympics
    Tokyo

    World bank president
    World Bank Group President Jim Yong Kim

    OPEC -Full Form
    Organization of the Petroleum Exporting Countries

    UPA Chairperson Sonia Gandhi laid the Foundation stone of HPCL Refinery-Petro chemical Complex in Rajasthan on 22 September 2013

    The President of India, Pranab Mukherjee inaugurated the First Engineers Conclave-2013 on 17 September 2013

    Hindustan Aeronautics Limited Delivered the First Hawk Mk-132 Advanced Jet Trainer Aircraft to the Indian Navy

    Mother Teresa Memorial International Award for Social Justice 2013 Presented to Sushmita Sen

    French Award Chevalier de la Legion d’Honneur for Anjali Gopalan

    Manna Dey, the legendary singer died at 94

    Lata Mangeshkar was Presented the First National Yash Chopra Memorial Award

    Nobel Prize -Nobel Prizes are announced by the Royal Swedish Academy of Sciences every year in the memory of Alfred Nobel.


    The Nobel Prize winners of 2013 in the different categories were as follows:


    Category Name of the Person Contribution
    Physiology or Medicine James Rothman for their groundbreaking work on how the cell organises its transport system
    Randy Schekman
    Thomas Suedhof
    Physics Peter Higgs for the theoretical discovery of a mechanism that contributes to our understanding of the origin of mass of subatomic particles.
    Francois Englert
    Chemistry Michael Levitt for the development of multi scale models for complex chemical systems
    Martin Karplus
    Arieh Warshel
    Peace The Organisation for the Prohibition of Chemical Weapons (OPCW) for its extensive efforts to eliminate chemical weapons
    Literature Alice Munro master of the contemporary short story
    Economics Eugene Fama for their work on creating a deeper knowledge of how market prices move
    Lars Peter Hansen
    Robert Shiller



    1. Afcons Infrastructure signed a memorandum of understanding with which state government of India for setting up 250-crore Rupees fabrication yard for the oil as well as gas platforms?
    a) Maharashtra Government
    b) Gujarat Government
    c) Tamil Nadu Government
    d) Karnataka Government
    Answer: (b) Gujarat Government

    2. The Supreme Court of India on 24 July 2013 slapped contempt notices on two Sahara firms for not complying with its order of refunding around 19000 crore rupees to investors. Which body filed the contempt petition against Sahara firms?
    a) The Insurance Regulatory and Development Authority (IRDA)
    b) Pension Fund Regulatory and Development Aulthority (PFRDA)
    c) Forward Markets Commission (FMC)
    d) Securities and Exchange Board of India (SEBI)
    Answer: (d) Securities and Exchange Board of India (SEBI)

    3. According to the recent satellite images, deforestation has dropped down by around one-third since 2000 in which rainforests of Africa?
    a) Zaïre basin
    b) Congo Basin
    c) Amazon Rainforest
    d) None of these
    Answer: (b) Congo Basin

    4. INSAT-3D was launched successfully by the European rocket from the spaceport of Kourou in French Guiana on 26 July 2013. What is the purpose of INSAT-3D?
    a) To provide technological experience in building and operating a satellite system
    b) To provide experience in building and operating a payload experiment three-axis stabilised communication satellite
    c) For multipurpose communication: business communication, developmental communication, and mobile communication
    d) Meteorological Satellite with advanced weather monitoring payloads
    Answer: (d) Meteorological Satellite with advanced weather monitoring payloads

    5. Which automobile company became first automaker to participate in Greenhouse Gas Reporting Programme in India on 23 July 2013?
    a) Ford Motor Company
    b) General Motors
    c) Maruti Suzuki
    d) Mahindra and Mahindra Limited
    Answer: (a) Ford Motor Company
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    krishna Banned

    HAL Management Trainee,Aeronautical engg question papers with answers

    Q. 1 – Q. 25 carry one mark each.
    Q.1 The constraint A2 = A on any square matrix A is satisfied for
    (A) the identity matrix only.
    (B) the null matrix only.
    (C) both the identity matrix and the null matrix. -Answer
    (D) no square matrix A.

    Q.2 The general solution of the differential equation


    (A) Ae-t + Be2t
    (B) Ae-2t + Be-t
    (C) Ae-2t + Bet
    (D) Aet + Be2t

    Q.3 An aircraft in trimmed condition has zero pitching moment at
    (A) its aerodynamic centre.
    (B) its centre of gravity.-Answer
    (C) 25% of its mean aerodynamic chord.
    (D) 50% of its wing root chord.

    Q.4 In an aircraft, constant roll rate can be produced using ailerons by applying
    (A) a step input.
    (B) a ramp input.
    (C) a sinusoidal input.
    (D) an impulse input.-Answer

    Q.5 For a symmetric airfoil, the lift coefficient for zero degree angle of attack is
    (A) – 1.0
    (B) 0.0 -Answer
    (C) 0.5
    (D) 1.0

    Q.6 The critical Mach number of an airfoil is attained when
    (A) the freestream Mach number is sonic.
    (B) the freestream Mach number is supersonic.
    (C) the Mach number somewhere on the airfoil is unity.-Answer
    (D) the Mach number everywhere on the airfoil is supersonic.

    Q.7 The shadowgraph flow visualization technique depends on
    (A) the variation of the value of density in the flow.
    (B) the first derivative of density with respect to spatial coordinate.
    (C) the second derivative of density with respect to spatialcoordinate.-Answer
    (D) the third derivative of density with respect to spatial coordinate.

    Q.8 The Hohmann ellipse used as earth-Mars transfer orbit has
    (A) apogee at earth and perigee at Mars.
    (B) both apogee and perigee at earth.
    (C) apogee at Mars and perigee at earth. -Answer
    (D) both apogee and perigee at Mars.

    Q.9 The governing equation for the static transverse deflection of a beam under an uniformly distributed load, according to Euler-Bernoulli (engineering) beam theory, is a
    (A) 2nd order linear homogenous partial differential equation.
    (B) 4th order linear non-homogenous ordinary differential equation.-Answer
    (C) 2nd order linear non-homogenous ordinary differential equation.
    (D) 4th order nonlinear homogenous ordinary differential equation.

    Q.10 The Poisson’s ratio,? of most aircraft grade metallic alloys has values in the range:
    (A) -1 =? =0
    (B) 0 =? =0.2
    (C) 0.2 =? =0.4 -Answer
    (D) 0.4 =? =0.5

    Q.11 The value of k for which the system of equations x + 2y + kz =1; 2x + ky +8z = 3 has no solution is
    (A) 0
    (B) 2
    (C) 4 -Answer
    (D) 8

    Q.12If u(t) is a unit step function, the solution of the differential equation image
    A-Answer

    D--Answer

    Q.14 During the ground roll manoeuvre of an aircraft, the force(s) acting on it parallel to the direction of motion
    (A) is thrust alone.
    (B) is drag alone.
    (C) are both thrust and drag.
    (D) are thrust, drag and a part of both weight and lift.-Answer

    Q.15 An aircraft in a steady climb suddenly experiences a 10% drop in thrust. After a new equilibrium is reached at the same speed, the new rate of climb is
    (A) lower by exactly 10%.
    (B) lower by more than 10%.-Answer
    (C) lower by less than 10%.
    (D) an unpredictable quantity.

    Q.16 In an aircraft, the dive manoeuvre can be initiated by
    (A) reducing the engine thrust alone.
    (B) reducing the angle of attack alone.
    (C) generating a nose down pitch rate. -Answer
    (D) increasing the engine thrust alone.

    Q.17 In an aircraft, elevator control effectiveness determines
    (A) turn radius.
    (B) rate of climb.
    (C) forward-most location of the centre of gravity.-Answer
    (D) aft-most location of the centre of gravity.

    Q.18 The Mach angle for a flow at Mach 2.0 is
    (A) 30o -Answer
    (B) 45o
    (C) 60o
    (D) 90o

    Q.19 For a wing of aspect ratio AR, having an elliptical lift distribution, the induced drag coefficient is

    B-Answer

    Q.20 Bernoulli’s equation is valid under steady state
    (A) only along a streamline in inviscid flow, and between any two points in potential flow.-Answer
    (B) between any two points in both inviscid flow and potential flow.
    (C) between any two points in inviscid flow, and only along a streamline in potential flow.
    (D) only along a streamline in both inviscid flow and potential flow.

    Q.21 The ratio of flight speed to the exhaust velocity for maximum propulsion efficiency is
    (A) 0.0
    (B) 0.5
    (C) 1.0 -Answer
    (D) 2.0

    Q.22 The ideal static pressure coefficient of a diffuser with an area ratio of 2.0 is
    (A) 0.25
    (B) 0.50
    (C) 0.75
    (D) 1.0

    Q.23 A rocket is to be launched from the bottom of a very deep crater on Mars for earth return. The specific impulse of the rocket, measured in seconds, is to be normalized by the acceleration due to
    gravity at
    (A) the bottom of the crater on Mars.
    (B) Mars standard “sea level”.
    (C) earth’s standard sea level. -Answer
    (D) the same depth of the crater on earth.

    Q.24 In a semi-monocoque construction of an aircraft wing, the skin and spar webs are the primary carriers of
    (A) shear stresses due to an aerodynamic moment component alone.
    (B) normal (bending) stresses due to aerodynamic forces.
    (C) shear stresses due to aerodynamic forces alone.
    (D) shear stresses due to aerodynamic forces and a moment component.-Answer


    Q.25 The logarithmic decrement measured for a viscously damped single degree of freedom system is 0.125. The value of the damping factor in % is closest to
    (A) 0.5
    (B) 1.0
    (C) 1.5
    (D) 2.0-Answer

    Q. 26 to Q. 55 carry two marks each.
    Questions Q.26 to Q.30 are numerical answer type. The answer to each of these questions is either a positive whole number, or a positive real number with maximum of 2 decimal places.


    Q.26 The integrationimage computed using trapezoidal rule with n = 4 intervals is ____.
    0.26 to 0.27

    Q.27 An aircraft has a steady rate of climb of 300 m/s at sea level and 150 m/s at 2500 m altitude. The time taken (in sec) for this aircraft to climb from 500 m altitude to 3000 m altitude is ____.
    Answer 13 to 14

    Q.28 An airfoil generates a lift of 80 N when operating in a freestream flow of 60 m/s. If the ambient pressure and temperature are 100 kPa and 290 K respectively (specific gas constant is 287 J/kg-K),
    the circulation on the airfoil in m2/s is ____.
    Answer 1.1 to 1.2

    Q.29 A rocket motor has combustion chamber temperature of 2600 K and the products have molecular weight of 25 g/mol and ratio of specific heats 1.2. The universal gas constant is 8314 J/kg-mole-K.
    The value of theoretical c* (in m/s) is ____.
    Answer-1430 to 1440

    Q.30 The mode shapes of an un-damped two degrees of freedom system are { } 1 0.5T and { } 1 0.675T - . The corresponding natural frequencies are 0.45 Hz and 1.2471 Hz. The maximum amplitude (in mm) of vibration of the first degree of freedom due to an initial displacement of
    {2 1}T (in mm) and zero initial velocities is ____.
    Answer-2

    Questions Q.31 to Q.55 are multiple choice type.31-35 questions image
    Q.31 The nth derivative of the function y=1/x+3 is
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    Q.32 The volume of a solid generated by rotating the region between semi-circle y =1- 1- x2 and straight line y = 1, about x axis, is


    Q.36 An aircraft is trimmed straight and level at true air speed (TAS) of 100 m/s at standard sea level(SSL). Further, pull of 5 N holds the speed at 90 m/s without re-trimming at SSL (air density = 1.22
    kg/m3). To fly at 3000 m altitude (air density = 0.91 kg/m3) and 120 m/s TAS without re-trimming,the aircraft needs
    (A) 1.95 N upward force.
    (B) 1.95 N downward force.-Answer
    (C) 1.85 N upward force.
    (D) 1.75 N downward force.

    Q.37 An oblique shock wave with a wave angle ß is generated from a wedge angle of ?. The ratio of the Mach number downstream of the shock to its normal component is
    (A) sin(ß–?) -Answer
    (B) cos(ß–?)
    (C) sin(?–ß)
    (D) cos(?–ß)

    Q.38 In a closed-circuit supersonic wind tunnel, the convergent-divergent (C-D) nozzle and test section are followed by a C-D diffuser to swallow the starting shock. Here, we should have the
    (A) diffuser throat larger than the nozzle throat and the shock located just at the diffuser throat.
    (B) diffuser throat larger than the nozzle throat and the shock located downstream of the diffuser throat.-Answer
    (C) diffuser throat of the same size as the nozzle throat and the shock located just at the diffuser throat.
    (D) diffuser throat of the same size as the nozzle throat and the shock located downstream of the diffuser throat.

    Q.39 A vortex flowmeter works on the principle that the Strouhal number of 0.2 is a constant over a wide range of flow rates. If the bluff-body diameter in the flowmeter is 20 mm and the piezo-electric transducer registers the vortex shedding frequency to be 10 Hz, then the velocity of the flow would be measured as
    (A) 0.1 m/s
    (B) 1 m/s -Answer
    (C) 10 m/s
    (D) 100 m/s

    Q.40 The stagnation temperatures at the inlet and exit of a combustion chamber are 600 K and 1200 K, respectively. If the heating value of the fuel is 44 MJ/kg and specific heat at constant pressure for air and hot gases are 1.005 kJ/kg.K and 1.147 kJ/kg.K respectively, the fuel-to-air ratio is
    (A) 0.0018
    (B) 0.018 -Answer
    (C) 0.18
    (D) 1.18

    Q.41 A solid propellant of density 1800 kg/m3 has a burning rate law r = 6.65 x 10-3p0.45 mm/s, where p is pressure in Pascals. It is used in a rocket motor with a tubular grain with an initial burning area
    of 0.314 m2. The characteristic velocity is 1450 m/s. What should be the nozzle throat diameter to achieve an equilibrium chamber pressure of 50 bar at the end of the ignition transient?
    (A) 35 mm
    (B) 38 mm -Answer
    (C) 41 mm
    (D) 45 mm

    Q.42 A bipropellant liquid rocket motor operates at a chamber pressure of 40 bar with a nozzle throat diameter of 50 mm. The characteristic velocity is 1540 m/s. If the fuel-oxidizer ratio of the propellant is 1.8, and the fuel density is 900 kg/m3, what should be the minimum fuel tank volume for a burn time of 8 minutes
    (A) 1.65 m3
    (B) 1.75 m3 -Answer
    (C) 1.85 m3
    (D) 1.95 m3

    Q.43 The propellant in a single stage sounding rocket occupies 60% of its initial mass. If all of it isexpended instantaneously at an equivalent exhaust velocity of 3000 m/s, what would be the altitude
    attained by the payload when launched vertically? [Neglect drag and assume acceleration due to gravity to be constant at 9.81 m/s2.]
    (A) 315 km
    (B) 335 km
    (C) 365 km
    (D) 385 km-Answer

    Q.44 The Airy stress function, f =a x2 +ß xy +? y2 for a thin square panel of size l ×l automaticallysatisfies compatibility. If the panel is subjected to uniform tensile stress, o s on all four edges, the
    traction boundary conditions are satisfied by
    (A) / 2; 0; / 2. o o a =s ß = ? =s -Answer
    (B) ; 0; . o o a =s ß = ? =s
    (C) 0; / 4; 0. o a = ß =s ? =
    (D) 0; / 2; 0. o a = ß =s ? =

    Q.45 The boundary condition of a rod under longitudinal vibration is changed from fixed-fixed to fixedfree.The fundamental natural frequency of the rod is now k times the original frequency, where k is
    (A)1/2-Answer
    (B) 2
    (C)1/square root2
    (D) squareroot 2

    Q.46 A spring-mass system is viscously damped with a viscous damping constant c. The energydissipated per cycle when the system is undergoing a harmonic vibration X d Cos? t is given by
    (A) 2d p c? X-Answer
    (B) 2d p? X
    (C) d p c? X
    (D) 2d p c? X

    Q.47 Buckling of the fuselage skin can be delayed by
    (A) increasing internal pressure.-Answer
    (B) placing stiffeners farther apart.
    (C) reducing skin thickness.
    (D) placing stiffeners farther and decreasing internal pressure.



    Q.48 The maximum distance that the centre of gravity can be behind aerodynamic centre without destabilizing the wing-tail combination is
    (A) 0.4 m
    (B) 1.4 m -Answer
    (C) 2.4 m
    (D) 3.4 m

    Q.49 The angle of incidence of tail to trim the wing-tail combination for a 5% static margin is
    (A) -1.4o -Answer
    (B) -0.4o
    (C) 0.4o
    (D) 1.4o

    Common Data for Questions 50 and 51:
    A thin long circular pipe of 10 mm diameter has porous walls and spins at 60 rpm about its own axis. Fluid is pumped out of the pipe such that it emerges radially relative to the pipe surface at a velocity of 1 m/s. [Neglect the effect of gravity.]

    Q.50 What is the radial component of the fluid’s velocity at a radial location 0.5 m from the pipe axis?
    (A) 0.01 m/s -Answer
    (B) 0.1 m/s
    (C) 1 m/s
    (D) 10 m/s

    Q.51 What is the tangential component of the fluid’s velocity at the same radial location as above?
    (A) 0.01 m/s
    (B) 0.03 m/s
    (C) 0.10 m/s
    (D) 0.31 m/s

    Linked Answer Questions
    Statement for Linked Answer Questions 52 and 53:
    Air at a stagnation temperature of 15oC and stagnation pressure 100 kPa enters an axial compressor with anabsolute velocity of 120 m/s. Inlet guide vanes direct this absolute velocity to the rotor inlet at an angle of 18o to the axial direction. The rotor turning angle is 27o and the mean blade speed is 200 m/s. The axial velocity is assumed constant through the stage.

    Q.52 The blade angle at the inlet of the rotor is
    (A) 25.5o
    (B) 38.5o
    (C) 48.5o
    (D) 59.5o

    Q.53 If the mass flow rate is 1 kg/s, the power required to drive the compressor is
    (A) 50.5 kW
    (B) 40.5 kW
    (C) 30.5 kW
    (D) 20.5 kW

    Statement for Linked Answer Questions 54 and 55:
    A thin-walled spherical vessel (1 m inner diameter and 10 mm wall thickness) is made of a material with 500MPa Y s = in both tension and compression.

    Q.54 The internal pressure Y p at yield, based on the von Mises yield criterion, if the vessel is floating in space, is approximately
    (A) 500MPa
    (B) 250MPa
    (C) 100MPa
    (D) 20MPa-Answer

    Q.55 If the vessel is evacuated (internal pressure = 0) and subjected to external pressure, yielding according to the von Mises yield criterion (assuming elastic stability until yield)
    (A) occurs at about half the pressure Y p .
    (B) occurs at about double the pressure Y p .
    (C) occurs at about the same pressure Y p .
    (D) never occurs.

    2012 GENERAL APTITUDE

    General Aptitude (GA) Questions

    Q. 56 – Q. 60 carry one mark each.
    Choose the most appropriate alternative from the options given below to complete the following sentence:

    I ___ to have bought a diamond ring.
    (A) have a liking
    (B) should have liked
    (C) would like-Answer
    (D) may like

    57 Choose the most appropriate alternative from the options given below to complete the following sentence:

    Food prices ___ again this month.
    (A) have raised
    (B) have been raising
    (C) have been rising -Answer
    (D) have arose

    Q.58Choose the most appropriate alternative from the options given below to complete the following sentence:
    The administrators went on to implement yet another unreasonable measure, arguing that the measures were already ___ and one more would hardly make a difference.

    (A) reflective
    (B) utopian
    (C) luxuriant
    (D) unpopular-Answer

    Q.59 Choose the most appropriate alternative from the options given below to complete the following sentence:
    To those of us who had always thought him timid, his ___ came as a surprise.

    (A) intrepidity -Answer
    (B) inevitability
    (C) inability
    (D) inertness
    Q.60 The arithmetic mean of five different natural numbers is 12. The largest possible value among the numbers is

    (A) 12
    (B) 40
    (C) 50 -Answer
    (D) 60

    Q. 61 - Q. 65 carry two marks each.
    Q. 61 Two policemen, A and B, fire once each at the same time at an escaping convict. The probability that A hits the convict is three times the probability that B hits the convict. If the probability of the convict not getting injured is 0.5, the probability that B hits the convict is

    (A) 0.14 -Answer
    (B) 0.22
    (C) 0.33
    (D) 0.40


    Q.62 The total runs scored by four cricketers P, Q, R, and S in years 2009 and 2010 are given in the following table:
    Player 2009 2010
    P 802 1008
    Q 765 912
    R 429 619
    S 501 701
    The player with the lowest percentage increase in total runs is

    (A) P
    (B) Q -Answer
    (C) R
    (D) S

    Q.63 If a prime number on division by 4 gives a remainder of 1, then that number can be expressed as
    (A) sum of squares of two natural numbers
    (B) sum of cubes of two natural numbers
    (C) sum of square roots of two natural numbers
    (D) sum of cube roots of two natural numbers

    Q.64 Two points (4, p) and (0, q) lie on a straight line having a slope of 3/4. The value of (p – q) is
    (A) -3
    (B) 0
    (C) 3 -Answer
    (D) 4

    Q.65 In the early nineteenth century, theories of social evolution were inspired less by Biology than by the conviction of social scientists that there was a growing improvement in social institutions. Progress was taken for granted and social scientists attempted to discover its
    laws and phases. Which one of the following inferences may be drawn with the greatest accuracy from the above passage?
    Social scientists
    (A) did not question that progress was a fact.-Answer
    (B) did not approve of Biology.
    (C) framed the laws of progress.
    (D) emphasized Biology over Social Sciences.
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    Q.32 The volume of a solid generated by rotating the region between semi-circle y =1- 1- x2 and straight line y = 1, about x axis, is


    Q.36 An aircraft is trimmed straight and level at true air speed (TAS) of 100 m/s at standard sea level(SSL). Further, pull of 5 N holds the speed at 90 m/s without re-trimming at SSL (air density = 1.22
    kg/m3). To fly at 3000 m altitude (air density = 0.91 kg/m3) and 120 m/s TAS without re-trimming,the aircraft needs
    (A) 1.95 N upward force.
    (B) 1.95 N downward force.-Answer
    (C) 1.85 N upward force.
    (D) 1.75 N downward force.

    Q.37 An oblique shock wave with a wave angle ß is generated from a wedge angle of ?. The ratio of the Mach number downstream of the shock to its normal component is
    (A) sin(ß–?) -Answer
    (B) cos(ß–?)
    (C) sin(?–ß)
    (D) cos(?–ß)

    Q.38 In a closed-circuit supersonic wind tunnel, the convergent-divergent (C-D) nozzle and test section are followed by a C-D diffuser to swallow the starting shock. Here, we should have the
    (A) diffuser throat larger than the nozzle throat and the shock located just at the diffuser throat.
    (B) diffuser throat larger than the nozzle throat and the shock located downstream of the diffuser throat.-Answer
    (C) diffuser throat of the same size as the nozzle throat and the shock located just at the diffuser throat.
    (D) diffuser throat of the same size as the nozzle throat and the shock located downstream of the diffuser throat.

    Q.39 A vortex flowmeter works on the principle that the Strouhal number of 0.2 is a constant over a wide range of flow rates. If the bluff-body diameter in the flowmeter is 20 mm and the piezo-electric transducer registers the vortex shedding frequency to be 10 Hz, then the velocity of the flow would be measured as
    (A) 0.1 m/s
    (B) 1 m/s -Answer
    (C) 10 m/s
    (D) 100 m/s

    Q.40 The stagnation temperatures at the inlet and exit of a combustion chamber are 600 K and 1200 K, respectively. If the heating value of the fuel is 44 MJ/kg and specific heat at constant pressure for air and hot gases are 1.005 kJ/kg.K and 1.147 kJ/kg.K respectively, the fuel-to-air ratio is
    (A) 0.0018
    (B) 0.018 -Answer
    (C) 0.18
    (D) 1.18

    Q.41 A solid propellant of density 1800 kg/m3 has a burning rate law r = 6.65 x 10-3p0.45 mm/s, where p is pressure in Pascals. It is used in a rocket motor with a tubular grain with an initial burning area
    of 0.314 m2. The characteristic velocity is 1450 m/s. What should be the nozzle throat diameter to achieve an equilibrium chamber pressure of 50 bar at the end of the ignition transient?
    (A) 35 mm
    (B) 38 mm -Answer
    (C) 41 mm
    (D) 45 mm

    Q.42 A bipropellant liquid rocket motor operates at a chamber pressure of 40 bar with a nozzle throat diameter of 50 mm. The characteristic velocity is 1540 m/s. If the fuel-oxidizer ratio of the propellant is 1.8, and the fuel density is 900 kg/m3, what should be the minimum fuel tank volume for a burn time of 8 minutes
    (A) 1.65 m3
    (B) 1.75 m3 -Answer
    (C) 1.85 m3
    (D) 1.95 m3

    Q.43 The propellant in a single stage sounding rocket occupies 60% of its initial mass. If all of it isexpended instantaneously at an equivalent exhaust velocity of 3000 m/s, what would be the altitude
    attained by the payload when launched vertically? [Neglect drag and assume acceleration due to gravity to be constant at 9.81 m/s2.]
    (A) 315 km
    (B) 335 km
    (C) 365 km
    (D) 385 km-Answer

    Q.44 The Airy stress function, f =a x2 +ß xy +? y2 for a thin square panel of size l ×l automaticallysatisfies compatibility. If the panel is subjected to uniform tensile stress, o s on all four edges, the
    traction boundary conditions are satisfied by
    (A) / 2; 0; / 2. o o a =s ß = ? =s -Answer
    (B) ; 0; . o o a =s ß = ? =s
    (C) 0; / 4; 0. o a = ß =s ? =
    (D) 0; / 2; 0. o a = ß =s ? =

    Q.45 The boundary condition of a rod under longitudinal vibration is changed from fixed-fixed to fixedfree.The fundamental natural frequency of the rod is now k times the original frequency, where k is
    (A)1/2-Answer
    (B) 2
    (C)1/square root2
    (D) squareroot 2

    Q.46 A spring-mass system is viscously damped with a viscous damping constant c. The energydissipated per cycle when the system is undergoing a harmonic vibration X d Cos? t is given by
    (A) 2d p c? X-Answer
    (B) 2d p? X
    (C) d p c? X
    (D) 2d p c? X

    Q.47 Buckling of the fuselage skin can be delayed by
    (A) increasing internal pressure.-Answer
    (B) placing stiffeners farther apart.
    (C) reducing skin thickness.
    (D) placing stiffeners farther and decreasing internal pressure.



    Q.48 The maximum distance that the centre of gravity can be behind aerodynamic centre without destabilizing the wing-tail combination is
    (A) 0.4 m
    (B) 1.4 m -Answer
    (C) 2.4 m
    (D) 3.4 m

    Q.49 The angle of incidence of tail to trim the wing-tail combination for a 5% static margin is
    (A) -1.4o -Answer
    (B) -0.4o
    (C) 0.4o
    (D) 1.4o

    Common Data for Questions 50 and 51:
    A thin long circular pipe of 10 mm diameter has porous walls and spins at 60 rpm about its own axis. Fluid is pumped out of the pipe such that it emerges radially relative to the pipe surface at a velocity of 1 m/s. [Neglect the effect of gravity.]

    Q.50 What is the radial component of the fluid’s velocity at a radial location 0.5 m from the pipe axis?
    (A) 0.01 m/s -Answer
    (B) 0.1 m/s
    (C) 1 m/s
    (D) 10 m/s

    Q.51 What is the tangential component of the fluid’s velocity at the same radial location as above?
    (A) 0.01 m/s
    (B) 0.03 m/s
    (C) 0.10 m/s
    (D) 0.31 m/s

    Linked Answer Questions
    Statement for Linked Answer Questions 52 and 53:
    Air at a stagnation temperature of 15oC and stagnation pressure 100 kPa enters an axial compressor with anabsolute velocity of 120 m/s. Inlet guide vanes direct this absolute velocity to the rotor inlet at an angle of 18o to the axial direction. The rotor turning angle is 27o and the mean blade speed is 200 m/s. The axial velocity is assumed constant through the stage.

    Q.52 The blade angle at the inlet of the rotor is
    (A) 25.5o
    (B) 38.5o
    (C) 48.5o
    (D) 59.5o

    Q.53 If the mass flow rate is 1 kg/s, the power required to drive the compressor is
    (A) 50.5 kW
    (B) 40.5 kW
    (C) 30.5 kW
    (D) 20.5 kW

    Statement for Linked Answer Questions 54 and 55:
    A thin-walled spherical vessel (1 m inner diameter and 10 mm wall thickness) is made of a material with 500MPa Y s = in both tension and compression.

    Q.54 The internal pressure Y p at yield, based on the von Mises yield criterion, if the vessel is floating in space, is approximately
    (A) 500MPa
    (B) 250MPa
    (C) 100MPa
    (D) 20MPa-Answer

    Q.55 If the vessel is evacuated (internal pressure = 0) and subjected to external pressure, yielding according to the von Mises yield criterion (assuming elastic stability until yield)
    (A) occurs at about half the pressure Y p .
    (B) occurs at about double the pressure Y p .
    (C) occurs at about the same pressure Y p .
    (D) never occurs.

    2012 GENERAL APTITUDE

    General Aptitude (GA) Questions

    Q. 56 – Q. 60 carry one mark each.
    Choose the most appropriate alternative from the options given below to complete the following sentence:

    I ___ to have bought a diamond ring.
    (A) have a liking
    (B) should have liked
    (C) would like-Answer
    (D) may like

    57 Choose the most appropriate alternative from the options given below to complete the following sentence:

    Food prices ___ again this month.
    (A) have raised
    (B) have been raising
    (C) have been rising -Answer
    (D) have arose

    Q.58Choose the most appropriate alternative from the options given below to complete the following sentence:
    The administrators went on to implement yet another unreasonable measure, arguing that the measures were already ___ and one more would hardly make a difference.

    (A) reflective
    (B) utopian
    (C) luxuriant
    (D) unpopular-Answer

    Q.59 Choose the most appropriate alternative from the options given below to complete the following sentence:
    To those of us who had always thought him timid, his ___ came as a surprise.

    (A) intrepidity -Answer
    (B) inevitability
    (C) inability
    (D) inertness
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    krishna Banned

    Q.60 The arithmetic mean of five different natural numbers is 12. The largest possible value among the numbers is

    (A) 12
    (B) 40
    (C) 50 -Answer
    (D) 60

    Q. 61 - Q. 65 carry two marks each.
    Q. 61 Two policemen, A and B, fire once each at the same time at an escaping convict. The probability that A hits the convict is three times the probability that B hits the convict. If the probability of the convict not getting injured is 0.5, the probability that B hits the convict is

    (A) 0.14 -Answer
    (B) 0.22
    (C) 0.33
    (D) 0.40


    Q.62 The total runs scored by four cricketers P, Q, R, and S in years 2009 and 2010 are given in the following table:
    Player 2009 2010
    P 802 1008
    Q 765 912
    R 429 619
    S 501 701
    The player with the lowest percentage increase in total runs is

    (A) P
    (B) Q -Answer
    (C) R
    (D) S

    Q.63 If a prime number on division by 4 gives a remainder of 1, then that number can be expressed as
    (A) sum of squares of two natural numbers
    (B) sum of cubes of two natural numbers
    (C) sum of square roots of two natural numbers
    (D) sum of cube roots of two natural numbers

    Q.64 Two points (4, p) and (0, q) lie on a straight line having a slope of 3/4. The value of (p – q) is
    (A) -3
    (B) 0
    (C) 3 -Answer
    (D) 4

    Q.65 In the early nineteenth century, theories of social evolution were inspired less by Biology than by the conviction of social scientists that there was a growing improvement in social institutions. Progress was taken for granted and social scientists attempted to discover its
    laws and phases. Which one of the following inferences may be drawn with the greatest accuracy from the above passage?
    Social scientists
    (A) did not question that progress was a fact.-Answer
    (B) did not approve of Biology.
    (C) framed the laws of progress.
    (D) emphasized Biology over Social Sciences.
  6. krishna

    krishna Banned

    Sep 11, 2013



    1. Laminations of core are generally made of
    (a) case iron
    (b) carbon
    (c) silicon steel
    (d) stainless steel
    Ans: c
    2. Which of the following could be lamina-proximately the thickness of lamina-tions of a D.C. machine ?
    (a) 0.005 mm
    (b) 0.05 mm
    (c) 0.5 m
    (d) 5 m
    Ans: c
    3. The armature of D.C. generator is laminated to
    (a) reduce the bulk
    (b) provide the bulk
    (c) insulate the core
    (d) reduce eddy current loss
    Ans: d
    4. The resistance of armature winding depends on
    (a) length of conductor
    (b) cross-sectional area of the conductor
    (c) number of conductors
    (d) all of the above
    Ans: d
    5. The field coils of D.C. generator are usually made of
    (a) mica
    (b) copper
    (c) cast iron
    (d) carbon
    Ans: b
    6. The commutator segments are connected to the armature conductors by means of
    (a) copper lugs
    (b) resistance wires
    (c) insulation pads
    (d) brazing
    Ans: a

    7. In a commutator
    (a) copper is harder than mica
    (b) mica and copper are equally hard
    (c) mica is harder than copper
    (d) none of the above
    Ans: c

    8. In D.C. generators the pole shoes are fastened to the pole core by
    (a) rivets
    (b) counter sunk screws
    (c) brazing
    (d) welding
    Ans: b

    9. According to Fleming's right-hand rule for finding the direction of induced e.m.f., when middle finger points in the direction of induced e.m.f., forefinger will point in the direction of
    (a) motion of conductor
    (b) lines of force
    (c) either of the above
    (d) none of the above
    Ans: b

    10. Fleming's right-hand rule regarding direction of induced e.m.f., correlates
    (a) magnetic flux, direction of current flow and resultant force
    (b) magnetic flux, direction of motion and the direction of e.m.f. induced
    (c) magnetic field strength, induced voltage and current
    (d) magnetic flux, direction of force and direction of motion of conductor
    Ans: b

    11. While applying Fleming's right-hand rule to And the direction of induced e.m.f., the thumb points towards
    (a) direction of induced e.m.f.
    (b) direction of flux
    (c) direction of motion of the conductor if forefinger points in the direction of generated e.m.f.
    (d) direction of motion of conductor, if forefinger points along the lines of flux
    Ans: d

    12. The bearings used to support the rotor shafts are generally
    (a) ball bearings
    (b) bush bearings
    (c) magnetic bearmgs
    (d) needle bearings
    Ans: a

    13. In D.C. generators, the cause of rapid brush wear may be
    (a) severe sparking
    (b) rough commutator surface
    (c) imperfect contact
    (d) any of the above
    Ans: d

    14. In lap winding, the number of brushes is always
    (a) double the number of poles
    (b) same as the number of poles
    (c) half the number of poles
    (d) two
    Ans: b

    15. For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f. ?
    (a) Lap winding
    (b) Wave winding
    (c) Either of (a) and (b) above
    (d) Depends on other features of design
    Ans: b

    16. In a four-pole D.C. machine
    (a) all the four poles are north poles
    (b) alternate poles are north and south
    (c) all the four poles are south poles
    (d) two north poles follow two south poles
    Ans: b

    17. Copper brushes in D.C. machine are used
    (a) where low voltage and high currents are involved
    (b) where high voltage and small cur-rents are involved
    (c) in both of the above cases
    (d) in none of the above cases
    Ans: a

    18. A separately excited generator as compared to a self-excited generator
    (a) is amenable to better voltage con-trol
    (b) is more stable
    (c) has exciting current independent of load current
    (d) has all above features
    Ans: d

    19. In case of D.C. machines, mechanical losses are primary function of
    (a) current
    (b) voltage
    (c) speed
    (d) none of above
    Ans: c

    20. Iron losses in a D.C. machine are independent of variations in
    (a) speed
    (b) load
    (c) voltage
    (d) speed and voltage
    Ans: b

    21. In D.C. generators, current to the external circuit from armature is given through
    (a) commutator
    (b) solid connection
    (c) slip rings
    (d) none of above
    Ans: a

    23. Brushes of D.C. machines are made of
    (a) carbon
    (b) soft copper
    (c) hard copper
    (d) all of above
    Ans: a

    24. If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by
    (a)Blv
    (b)Blv2
    (c)Bl2v
    (d)Bl2v2
    Ans: a

    25. In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be
    (a) 4
    (b) 8
    (c) 16
    (d) 32
    Ans: b

    26. The material for commutator brushes is generally
    (a) mica
    (b) copper
    (c) cast iron
    (d) carbon
    Ans: d

    27. The insulating material used between the commutator segments is normally
    (a) graphite
    (b) paper
    (c) mica
    (d) insulating varnish
    Ans: c

    28. In D.C. generators, the brushes on commutator remain in contact with conductors which
    (a) lie under south pole
    (b) lie under north pole
    (c) lie under interpolar region
    (d) are farthest from the poles
    Ans: c

    29. If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be
    (a) demagnetisation only
    (b) cross magnetisation as well as magnetisation
    (c) crossmagnetisation as well as demagnetising
    (d) cross magnetisation only
    Ans: c

    30. Armature reaction of an unsaturated D.C. machine is
    (a) crossmagnetising
    (b) demagnetising
    (c) magnetising
    (d) none of above
    Ans: a

    31. D.C. generators are connected to the busbars or disconnected from them only under the floating condition
    (a) to avoid sudden loading of the primemover
    (b) to avoid mechanicaljerk to the shaft
    (c) to avoid burning of switch contacts
    (d) all above
    Ans: d

    32. Eddy currents are induced in the pole shoes of a D.C. machine due to
    (a) oscillating magnetic field
    (b) pulsating magnetic flux
    (c) relative rotation between field and armature
    (d) all above
    Ans: c

    33. In a D.C. machine, short-circuited field coil will result in
    (a) odour of barning insulation
    (b) unbalanced magnetic pull producing vibrations
    (c) reduction of generated voltage for which excitation has to be increased to maintain the voltage
    (d) all above


    34. Equilizer rings are required in case armature is
    (a) wave wound
    (b) lap wound
    (c) delta wound
    (d) duplex wound
    Ans: b

    35. Welding generator will have
    (a) lap winding
    (b) wave winding
    (c) delta winding
    (d) duplex wave winding
    Ans: a

    36. In case of D.C. machine winding, number of commutator segments is equal to
    (a) number of armature coils
    (b) number of armature coil sides
    (c) number of armature conductors
    (d) number of armature turns
    Ans: a

    37. For a D.C. machines laboratory following type of D.C. supply will be suitable
    (a) rotary converter
    (b) mercury are rectifier
    (c) induction motor D.C. generator set
    (d) synchronous motor D.C. generator set
    Ans: c

    38. The function of pole shoes in the case of D.C. machine is
    (a) to reduce the reluctance of the magnetic path
    (b) to spread out the flux to achieve uniform flux density
    (c) to support the field coil
    (d) to discharge all the above functions
    Ans: d

    39. In the case of lap winding resultant pitch is
    (a) multiplication of front and back pitches
    (b) division of front pitch by back pitch
    (c) sum of front and back pitches
    (d) difference of front and back pitches
    Ans: d

    40. A D.C. welding generator has
    (a) lap winding
    (b) wave moving
    (c) duplex winding
    (d) any of the above
    Ans: a

    41. Which of the following statement about D.C. generators is false ?
    (a) Compensating winding in a D.C. machine helps in commutation
    (b) In a D. C. generator interpoles winding is connected in series with the armature winding
    (c) Back pitch and front pitch are both odd and approximately equal to the pole pitch
    (d) Equilizing bus bars are used with parallel running of D.C. shunt generators
    Ans: d

    42. The demagnetising component of armature reaction in a D.C. generator
    (a) reduces generator e.m.f.
    (b) increases armature speed
    (c) reduces interpoles flux density
    (d) results in sparking trouble
    Ans: a

    43. Magnetic field in a D.C. generator is produced by
    (a) electromagnets
    (b) permanent magnets
    (c) both (a) and (b)
    (d) none of the above
    Ans: a

    44. The number of brushes in a commutator depends on
    (a) speed of armature
    (b) type of winding
    (c) voltage
    (d) amount of current to be collected
    Ans: d

    45. Compensating windings are used in D.C. generators
    (a) mainly to reduce the eddy currents by providing local short-circuits
    (b) to provide path for the circulation of cooling air
    (c) to neutralise the cross-magnetising effect of the armature reaction
    (d) none of the above
    Ans: c

    46. Which of the following components of a D.C, generator plays vital role for providing direct current of a D.C. generator ?
    (a) Dummy coils
    (b) Commutator
    (c) Eye bolt
    (d) Equilizer rings
    Ans: b
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    krishna Banned

    47. In a D.C. generator the ripples in the direct e.m.f. generated are reduced by
    (a) using conductor of annealed copper
    (b) using commutator with large number of segments
    (c) using carbon brushes of superior quality
    (d) using equiliser rings
    Ans: c

    48. In D.C. generators, lap winding is used for
    (a) high voltage, high current
    (b) low voltage, high current
    (c) high voltage, low current
    (d) low voltage, low current
    Ans: b

    49. Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be
    (a) 2 : 3
    (b) 3 : 1
    (c) 3 : 2
    (d) 1 : 3
    Ans: b

    50. The voltage drop for which of the following types of brush can be expected to be least ?
    (a) Graphite brushes
    (b) Carbon brushes
    (c) Metal graphite brushes
    (d) None of the above
    Ans: c

    51. The e.m.f. generated by a shunt wound D.C. generator isE. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be
    (a) E/2
    (b) 2E
    (c) slightly less than E
    (d) E
    Ans: b

    52. In a D.C. generator the actual flux distribution depends upon
    (a) size of air gap
    (b) shape of the pole shoe
    (c) clearance between tips of the ad¬jacent pole shoes
    (d) all of the above
    Ans:

    53. The armature core of a D.C. generator is usually made of
    (a) silicon steel
    (b) copper
    (c) non-ferrous material
    (d) cast-iron
    Ans: a

    9.63. Satisfactory commutation of D.C. machines requires
    (a) brushes should be of proper grade and size
    (b) brushes should smoothly run in the holders
    (c) smooth, concentric commutator properly undercut
    (d) all of the above
    Ans: d

    54. Open circuited armature coil of a D.C. machine is
    (a) identified by the scarring of the commutator segment to which open circuited coil is connected
    (b) indicated by a spark completely around the commutator
    (c) both (a) and (b)
    (d) none of the above
    Ans: c

    55. In a D.C. machine, fractional pitch winding is used
    (a) to increase the generated voltage
    (b) to reduce sparking
    (c) to save the copper because of shorter end connections
    (d) due to (b) and (c) above
    Ans:

    56. For the parallel operation of two or more D.C. compound generators, we should ensure that
    (a) voltage of the incoming generator should be same as that of bus bar
    (b) polarity of incoming generator should be same as that of bus bar
    (c) all the series fields should be run in parallel by means of equilizer connection
    (d) series fields of all generators should be either on positive side or negative side of the armature
    (e) all conditions mentioned above should be satisfied
    Ans: d

    57. D.C. series generator is used
    (a) to supply traction load
    (b) to supply industrial load at constant voltage
    (c) voltage at the toad end of the feeder
    (d) for none of the above purpose
    Ans: c

    58. Following D.C. generator will be in a position to build up without any residual magnetism in the poles
    (a) series generator
    (b) shunt generator
    (c) compound generator
    (d) self-excited generator
    Ans: d

    59. Interpole flux should be sufficient to
    (a) neutralise the commutating self induced e.m.f.
    (b) neutralise the armature reaction flux
    (c) neutralise both the armature reaction flux as well as commutating e.m.f. induced in the coil
    (d) perform none of the above functions
    Ans: c

    60. D.C. generator generally preferred for charging automobile batteries is
    (a) series generator
    (b) shunt generator
    (c) long shunt compound generator
    (d) any of'the above
    Ans: c

    61. In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when
    (a) r.p.m. is more than 300
    (b) r.p.m. is less than 300
    (c) number of poles is 4
    (d) number of poles is 2
    Ans: d

    62. Permeance is the reciprocal of
    (a) flux density
    (b) reluctance
    (c) ampere-turns
    (d) resistance
    Ans: b

    63. In D.C. generators the polarity of the interpoles
    (a) is the same as that of the main pole ahead
    (b) is the same as that of the immediately preceding pole
    (c) is opposite to that of the main pole ahead
    (d) is neutral as these poles do not play part in generating e.m.f.
    Ans: a

    64. The e.m.f. generated in a D.C. generator is directly proportional to
    (a) flux/pole
    (b) speed of armature
    (c) number of poles
    (d) all of the above
    Ans: b

    65. In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when
    (a) there is no load on|he generator
    (b) the generator runs on full load
    (c) the generator runs on overload
    (d) the generator runs on designed speed
    Ans: a

    66. In a D.C. generator in order to reduce sparking at brushes, the self-induced e.m.f. in the coil is neutralised by all of the following except
    (a) interpoles
    (b) dummy coils
    (c) compensating winding
    (d) shifting of axis of brushes
    Ans: b

    67. In D.C. generators on no-load, the air gap flux distribution in space is
    (a) sinusoidal
    (b) triangular
    (c) pulsating
    (d) flat topped
    Ans: d

    68. A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly
    (a) 150 V
    (b) 175 V
    (c) 240 V
    (d) 290 V
    Ans: c

    69. The purpose of providing dummy coils in a generator is
    (a) to reduce eddy current losses
    (b) to enhance flux density
    (c) to amplify voltage
    (d) to provide mechanical balance for the rotor
    Ans: d

    70. In a shunt generator the voltage build up is generally restricted by
    (a) speed limitation
    (b) armature heating
    (c) insulation restrictions
    (d) saturation of iron
    Ans:

    71. If a D.C. generator fails to build up the probable cause could not be
    (a) imperfect brush contact
    (b) field resistance less than the critical resistance
    (c) no residual magnetism in the generator
    (d) faulty shunt connections tending to reduce the residual magnetism
    Ans: b

    72. Flashing the field of D.C. generator means
    (a) neutralising residual magnetism
    (b) creating residual magnetism by a D.C. source
    (c) making the magnetic losses of forces parallel
    (d) increasing flux density by adding extra turns of windings on poles
    Ans: b

    73. The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be
    (a) 640 V
    (b) 620 V
    (c) 600 V
    (d) 580 V
    Ans: d

    74. In a D.C. generator the critical resistance refers to the resistance of
    (a) brushes
    (b) field
    (c) armature
    (d) load
    Ans: b

    75. To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them
    (a) just ahead of magnetic neutral axis
    (b) in magnetic neutral axis
    (c) just behind the magnetic neutral axis
    Ans: a

    76. Armature coil is short circuited by brushes when it lies
    (a) along neutral axis
    (b) along field axis
    (c) in any of the above positions
    (d) in none of the above positions
    Ans: a

    77. A cumulatively compounded long shunt generator when operating as a motor would be
    (a) cumulatively compounded long shunt
    (b) differentially compounded long shunt
    (c) cumulatively compounded short shunt
    (d) differentially compounded short shunt
    Ans: b

    78. To avoid formation of grooves in the commutator of a D.C. machine
    (a) the brushes of opposite polarity should track each other
    (b) the brushes of same polarity should track each other
    (c) brush position has no effect on the commutator grooving
    Ans: a

    79. The following constitute short-circuit in the armature winding.
    (a) Insulation failure between two com-mutator bars
    (6) Insulation failure between two turns of a coil
    (c) Two of more turns of the same coil getting grounded
    (d) All of the above
    Ans: d

    80. The rapid wear of brushes takes place due to
    (a) abrasion from dust
    (b) excessive spring pressure
    (c) rough commutator bars
    (d) high mica insulation between com-mutation bars
    (e) all of the above factors
    Ans: e

    81. Number of tappings for each equilizer ring is equal to
    (a) number of pole pairs
    (b) number of poles
    (c) number of parallel paths
    (d) number of commutator segments
    Ans: a

    82. A D.C. generator can be considered as
    (a) rectifier
    (b) primemover
    (c) rotating amplifier
    (d) power pump
    Ans: c

    83. In any rotating machine that part which houses the conductors and in which e.m.f. induced is to be utilised is called
    (a) rotor
    (b) stator
    (c) field
    (d) armature
    Ans: d

    84. In a D.C. machine stray loss is the sum of
    (a) total copper loss and mechanical loss
    (b) armature copper loss and iron loss
    (c) shunt field copper loss and mechanical loss
    (d) iron loss and mechanical loss
    Ans: d

    85. Lap winding is composed of
    (a) any even number of conductors
    (b) any odd number of conductors
    (c) that even number which is exact multiple of poles + 2
    (d) that even number which is exact multiple of poles
    Ans: a

    86. In a D.C. generator in case the resistance of the field winding is increased, then output voltage will
    (a) increase
    (b) decrease
    (c) remain unaffected
    (d) fluctuate heavily
    Ans: b

    87. An exciter for a turbo generator is a
    (a) separately excited generator
    (b) shunt generator
    (c) series generator
    (d) compound generator
    Ans: b

    88. In case of a flat compounded generator
    (a) voltage generated is less than the rated voltage
    (b) generated voltage is proportional to the load on the generator
    (c) voltage remains constant irrespec¬tive of the load
    (d) speed varies in proportion to the load on the generator
    Ans: c

    89. Which of the following generator will have negligible terminal voltage while running on no-load ?
    (a) Series generator
    (b) Shunt generator
    (c) Compound generator
    (d) Separately excited generator
    Ans: a

    90. Which of the following D.C. generators will be in a position to build up without any residual magnetism in the poles ?
    (a) Series generator
    (b) Shunt generator
    (c) Compound generator
    (d) None of the above
    Ans: d
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    krishna Banned

    91. In over compounded generator, full load terminal voltage is
    (a) almost zero
    (b) less than noload terminal voltage
    (c) more than noload terminal voltage
    (d) equal to no-load terminal voltage
    Ans: c

    92. In a level compounded D.C. generator, full load terminal voltage is
    (a) negligibly low
    (b) equal to no-load terminal voltage
    (c) more than no-load terminal voltage
    (d) less than no-load terminal voltage
    Ans: b

    93. The terminal voltage of a D.C. shunt generator drops on load because of all of the following reasons except
    (a) armature reaction
    (b) armature resistance drop
    (c) field weakening due to armature reaction and armature
    (d) commutation
    Ans: d

    94. In a D.C. generator
    (a) external resistance = internal char-acteristic - armature reaction
    (b) internal characteristic = magnetisation characteristic - ohmic drop
    (c) external characteristic = magnetisation characteristic - ohmic drop - armature reaction
    (d) magnetisation characteristic = external characteristic
    Ans: c

    95. A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave
    (a) will be zero
    (b) will be of 5 Hz
    (c) willbeof5xiVHz
    (d) will be of v Hz 5
    Ans: b

    96. A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be
    (a) zero
    (b) about 2 V
    (c) about 50 V
    (d) 220 V
    Ans: b

    97. In a separately excited generator supplying rated load the armature reaction ,
    (a) is always present
    (b) is always absent
    (c) may be sometimes present
    (d) none of the above
    Ans: a

    98. If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be
    (a) zero
    (b) small
    (c) the same as rated voltage
    (d) high
    Ans: a

    99. Armature reaction in a generator results in
    (a) demagnetisation of leading pole tip and magnetisation of trailing pole tip
    (b) demagnetisation of trailing pole tip and magnetisation of leading pole tip
    (c) damagnetising the centre of all poles
    (d) magnetising the centre of all poles
    Ans: a

    100. Following energized winding of a D.C. machine should not be opened as it would produce high inductive voltage which may be dangerous to personnel and may cause its own insulation failure.
    (a) Series field
    (b) Compensating field
    (c) Inter pole field
    (d) Shunt field
    Ans: d

    101. Wave winding is composed of
    (a) any even number of conductors
    (b) any odd number of conductors
    (c) that even number which is exact multiple of poles + 2
    (d) that even number which is exact multiple of poles
    Ans: c

    102. The critical resistance of the D.C. generator is the resistance of
    (a) field
    (b) brushes
    (c) armature
    (d) load
    Ans: a

    103. When two D.C. series generators are running in parallel, an equilizer bar is used
    (a) to increase the speed and hence generated e.m.f.
    (b) to increase the series flux
    (c) so that two similar machines will pass approximately equal currents to the load
    (d) to reduce the combined effect of ar-mature reaction of both machines
    Ans: c

    104. Which of the following generating machine will offer constant voltage on all loads ?
    (a) Self-excited generator
    (b) Separately excited generator
    (c) Level compounded generator .
    (d) All of the above
    Ans: c

    105. Which of the following generators will be preferred if they are required to be run in parallel ?
    (a) Shunt generators
    (b) Series generators
    (c) Compound generators
    (d) None of the above
    Ans: a

    106. Two generators are running in parallel. One of the generators may run as motor for which of the following reasons ?
    (a) The direction of that generator is reversed
    (b) The speed of that generator is increased
    (c) The field of that generator is weakened
    (d) That generator takes large share of loads
    Ans: d

    107. A D.C. generator works on the principle of
    (a) Lenz's law
    (b) Ohm's law
    (c) Faraday's law of electromagnetic induction
    (d) none of the above
    Ans: c

    108. A series generator can self-excite
    (a) only if the load current is zero
    (b) only if the load current is not zero
    (c) irrespective of the value of load current
    (d) none of the above
    Ans: b

    109. A shunt generator can self-excite
    (a) only if the resistance of the field circuit is less than critical value
    (b) only if the resistance of the field circuit is greater than critical value
    (c) irrespective of the value of the resis-tance in the field circuit
    Ans: a

    110. The terminal voltage of a series generator is 150 V when the load current is 5 A. If the load current is increased to 10 A, the terminal voltage will be
    (a) 150 V
    (b) less than 150 V
    (c) greater than 150 V
    (d) none of the above
    Ans: c

    111. The open circuit voltage of a compound generator is 250 V. At full load the terminal voltage
    (a) will be less than 250 V
    (b) will always be 250 V
    (c) may be greater or less than 250 V
    (d) none of the above
    Ans: c

    112. Two D.C. shunt generators, each with armature resistance of 0.02 ohm and field resistance of 50 ohm run in parallel and supply a total current of 1000 amperes to the load circuit. If their e.m.fs. are 270 V and 265 V, their bus bar voltage will be
    (a) 270 V
    (b) 267.5 V
    (c) 265 V
    (d) 257.4 V
    Ans: b

    113. The essential condition for parallel operation of two D.C. generators is that they have '
    (a) same kW rating
    (b) the same operation r.p.m.
    (c) the same drooping voltage charac-teristics
    (d) same percentage regulation
    Ans: c

    114. When two D.C. generators are running in parallel an equilizer bar is used
    (a) to increase the series flux
    (b) to increase the generated e.m.f.
    (c) to reduce the combined effect of ar-mature reaction of both the machines
    (d) so that the two identical machines will pass approximately equal currents to the load
    Ans: d

    115. With a D.C. generator which of the following regulation is preferred ?
    (a) 100% regulation
    (b) infinite regulation
    (c) 50% regulation
    (d) 1% regulation
    Ans: d

    116. Which generator would you prefer for feeding long D.C. transmission lines ?
    (a) Series generator
    (b) Shunt generator
    (c) Over compound generator
    (d) Flat compound generator
    Ans: c

    117. In a D.C. generator the critical resistance can be increased by
    (a) increasing its field resistance
    (b) decreasing its field resistance
    (c) increasing its speed
    (d) decreasing its speed
    Ans: c

    118. The number of armature parallel paths in a two-pole D.C. generator having duplex lap winding is
    (a) 2
    (b) 4
    (c) 6
    (d) 8
    Ans: b

    119. For both lap and wave windings, there are as many commutator bars as the number of
    (a) slots
    (b) armature conductors
    (c) winding elements
    (d) poles
    Ans: c

    120. The series field of a short-shunt D.C. generator is excited by
    (a) external current
    (b) armature current
    (c) shunt current
    (d) load current
    Ans: d

    121. As a result of armature reaction, the reduction in the total mutual air gap flux in a D.C. generator is approximately
    (a) 40 percent
    (b) 25 percent
    (c) 10 percent
    (d) 5 percent
    Ans: d

    122. Shunt generators are most suited for stable parallel operation because of their
    (a) rising voltage characteristics
    (b) identical voltage characteristics
    (c) drooping voltage characteristics
    (d) linear voltage characteristics
    Ans: c

    123. The main factor which leads to unstable parallel operation of flat and over compounded generators is
    (a) their rising voltage characteristics
    (b) unequal number of turns in their series field windings
    (c) unequal speed regulation of their primemovers
    (d) unequal series field resistances
    Ans: a

    124. If a self excited D.C. generator after being installed, fails to build up on its first trial run, the first thing to do is to
    (a) reverse the field connections
    (b) increase the field resistance
    (c) increase the speed of primemover
    (d) check armature insulation resis¬tance
    Ans: a

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