Railways NTPC (Technical Ability) Vibration Analysis Question Bank

done Vibration Analysis Total Questions - 120

• question_answer1)
  A mass of 1 kg is attached to the end of a spring with a stiffness 0.7 N/mm. The critical damping coefficient of the system is:
  A)
  1.40 Ns/m                      done clear
  B)
  52.22 Ns/m done clear
  C)
  52.92 Ns/m                    done clear
  D)
  529.20 Ns/m done clear
  View Solution play_arrow

• question_answer2)
  Two heavy rotating masses are connected by shafts of lengths \[{{l}_{1}},{{l}_{2}}\] and \[{{l}_{3}}\] and the   corresponding diameters are \[{{d}_{1}},{{d}_{2}}\] and \[{{d}_{3.}}\]this system is reduced to a torsionally equivalent system having uniform diameter \[''{{d}_{1}}''\] of the shaft. The equivalent length of the shaft is:
  A)
  \[\frac{{{l}_{1}}+{{l}_{2}}+{{l}_{3}}}{3}\] done clear
  B)
  \[{{l}_{1}}+{{l}_{2}}{{\left( \frac{{{d}_{1}}}{{{d}_{2}}} \right)}^{3}}+{{l}_{3}}{{\left( \frac{{{d}_{1}}}{{{d}_{3}}} \right)}^{3}}\] done clear
  C)
  \[{{l}_{1}}+{{l}_{2}}{{\left( \frac{{{d}_{1}}}{{{d}_{2}}} \right)}^{4}}+{{l}_{3}}{{\left( \frac{{{d}_{1}}}{{{d}_{3}}} \right)}^{4}}\] done clear
  D)
  \[{{l}_{1}}+{{l}_{2}}+{{l}_{3}}\] done clear
  View Solution play_arrow

• question_answer3)
  The equation of free vibrations of a system is \[\ddot{x}+36\,\,{{\pi }^{2}}X=0.\] Its natural frequency is:
  A)
  \[46\text{ }Hz\]              done clear
  B)
  \[3\,\,\pi Hz\] done clear
  C)
  \[3\text{ }Hz\]                done clear
  D)
  \[6\,\pi Hz\] done clear
  View Solution play_arrow

• question_answer4)
  Which of the following methods can be used to determine the damping of machine element?

  1. Logarithmic method

  2. Band-width method

  3.  Rayleigh method

  4. Holzer method,

  Select the correct answer using the codes given below:

  Codes:
  A)
  1 and 3             done clear
  B)
  1 and 2 done clear
  C)
  3 and 4             done clear
  D)
  1, 3 and 4 done clear
  View Solution play_arrow

• question_answer5)
  If \[\frac{\omega }{{{\omega }_{n}}}=\sqrt{2}\] where \[\omega \] is the frequency of excitation and  \[{{\omega }_{n}}\] is the natural frequency of vibrations, then the transmissibility of vibrations will be:
  A)
  0.5                                done clear
  B)
  1.0 done clear
  C)
  1.5                                done clear
  D)
  2.0 done clear
  View Solution play_arrow

• question_answer6)
  A slender shaft supported on two hearings at its ends carries a disc with an eccentricity e from the axis of rotation. The critical speed of the shaft is N. If the disc is replaced by a second one of the same weight but mounted with an eccentricity 2e, critical speed of :he shaft in the second case is:
  A)
  \[\frac{1}{2}N\]                         done clear
  B)
  \[\frac{1}{\sqrt{2}}N\] done clear
  C)
  N                                  done clear
  D)
  2N done clear
  View Solution play_arrow

• question_answer7)
  An axial flow fan balanced at one speed often exhibits substantial vibrational effect when operated at other speeds, mainly due to:
  A)
  Primary critical speed effect done clear
  B)
  Secondary critical speed effect done clear
  C)
  Unbalanced parts of the fan done clear
  D)
  Aerodynamic unbalance done clear
  View Solution play_arrow

• question_answer8)
  For a disc mounted shaft to rotate with light side of disc out:  Where \[\beta =\frac{\omega }{{{\omega }_{c}}}\]
  A)
  \[\beta <1\]                    done clear
  B)
  \[\beta =1\] done clear
  C)
  \[\beta >1\]                    done clear
  D)
  \[\beta <<1\] done clear
  View Solution play_arrow

• question_answer9)
  When shaking force is transmitted through the spring, damping becomes detrimental when the ratio of its frequency to the natural frequency is greater than:
  A)
  0.25                              done clear
  B)
  0.50 done clear
  C)
  1.00                              done clear
  D)
  sqrt 2 done clear
  View Solution play_arrow

• question_answer10)
  When the mass of a critically damped single degree of freedom system is deflected from its equilibrium position and released, it will:
  A)
  Return to equilibrium position without oscillation done clear
  B)
  Oscillate with increasing time period done clear
  C)
  Oscillate with decreasing amplitude done clear
  D)
  Oscillate with constant amplitude done clear
  View Solution play_arrow

• question_answer11)
  Under logarithmic decrement, the amplitude of successive vibrations are:
  A)
  constant done clear
  B)
  In arithmetic progression done clear
  C)
  In geometric progression done clear
  D)
  In logarithmic progression done clear
  View Solution play_arrow

• question_answer12)
  The danger of breakage and vibration is maximum:
  A)
  Below critical speed         done clear
  B)
  near critical speed done clear
  C)
  Above critical speed        done clear
  D)
  none of the above done clear
  View Solution play_arrow

• question_answer13)
  With symbols having the usual meanings, the single degree of freedom system, \[m\ddot{x}+c\dot{x}+kx=F\sin \,\,\omega t\] represents:
  A)
  Free vibration with damping done clear
  B)
  Free vibration without damping done clear
  C)
  Forced vibration with damping done clear
  D)
  Forced vibration without damping done clear
  View Solution play_arrow

• question_answer14)
  A simple spring mass vibrating system has a natural frequency of N. If the spring, stiffness is halved and the mass is doubled, then the natural frequency will become:
  A)
  N/2                               done clear
  B)
  2N done clear
  C)
  4N                                done clear
  D)
  8N done clear
  View Solution play_arrow

• question_answer15)
  Rotating shafts tend to vibrate violently at whirling speeds because:
  A)
  The shafts are rotating at very high speeds done clear
  B)
  Bearing centre line coincides with the shaft axis done clear
  C)
  The system is unbalanced done clear
  D)
  Resonance is caused due to the heavy weight of the rotor. done clear
  View Solution play_arrow

• question_answer16)
  Critical speed of a shaft with a disc supported in between is equal to the natural frequency of the system in:
  A)
  Transverse vibrations done clear
  B)
  Torsional vibrations done clear
  C)
  Longitudinal vibrations done clear
  D)
  Longitudinal vibrations provided the shaft is vertical. done clear
  View Solution play_arrow

• question_answer17)
  In a automobile service station, an automobile is in a lifted up position by means of a hydraulic jack. A person working in the service station gave a tap to one rear wheel and made it rotate by one revolution. The rotation of another rear wheel is:
  A)
  Zero done clear
  B)
  Also one revolution in the same direction done clear
  C)
  Also one revolution but in the opposite direction done clear
  D)
  unpredictable done clear
  View Solution play_arrow

• question_answer18)
  In the statement "an eccentric mass rotating a 3000 rpm will create X times more unbalanced force than 50% of the same mass rotating at 300 rpm", 'X' stands for:
  A)
  10                                 done clear
  B)
  50 done clear
  C)
  100                               done clear
  D)
  200 done clear
  View Solution play_arrow

• question_answer19)
  A machine of 100 kg mass has a 20 kg rotor with 0.5 mm eccentricity. The mounting springs have stiffness 85 kN/m and damping is negligible. If the operating speed is \[20\pi \] rad/and the unit is constrained to move vertically, the dynamic amplitude of the machine will be:
  A)
  \[0.170\times {{10}^{-\,4}}m\]  done clear
  B)
  \[1.000\times {{10}^{-\,4}}m\] done clear
  C)
  \[1.274\times {{10}^{-\,4}}m\]  done clear
  D)
  \[2.540\times {{10}^{-\,4}}m\] done clear
  View Solution play_arrow

• question_answer20)
  Match the List I(Force transmissibility) with List II (frequency ratio) and select the correct answer using the codes given below the Lists:

  List-I (Force transmissibility)		List-II (Frequency ratio)
  A.	1	1.	\[\frac{\omega }{{{\omega }_{n}}}>\sqrt{2}\]
  B.	Less than 1	2.	\[\frac{\omega }{{{\omega }_{n}}}=\sqrt{2}\]
  C.	Greater than 1	3.	\[\frac{\omega }{{{\omega }_{n}}}>>\sqrt{2}\]
  D.	Tending to zero	4.	\[\frac{\omega }{{{\omega }_{n}}}<\sqrt{2}\]

  Codes:
  A)
  A\[\to \]1, B\[\to \]2, C\[\to \]3, D\[\to \]4 done clear
  B)
  A\[\to \]2, B\[\to \]1, C\[\to \]4, D\[\to \]3 done clear
  C)
  A\[\to \]2, B\[\to \]1, C\[\to \]3, D\[\to \]4 done clear
  D)
  A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]3 done clear
  View Solution play_arrow

• question_answer21)
  The equation of motion for a single degree of freedom system with viscous damping is: \[4\ddot{x}+9\dot{x}+16x=0.\] The damping ratio of the system is:     
  A)
  \[\frac{9}{128}\]                                    done clear
  B)
  \[\frac{9}{16}\] done clear
  C)
  \[\frac{9}{8\sqrt{2}}\]                done clear
  D)
  \[\frac{9}{8}\] done clear
  View Solution play_arrow

• question_answer22)
  The critical speed of a rotating shaft depends
  A)
  Mass                             done clear
  B)
  Stiffness                              done clear
  C)
  Mass and stiffness                     done clear
  D)
  Mass, stiffness and eccentricity.  done clear
  View Solution play_arrow

• question_answer23)
       Two heavy rotating masses are connected by shafts of length \[{{l}_{1}},{{l}_{2}}\] and \[{{l}_{3}}\] and the corresponding diameters are island (/3.This system is reduced to a torsionally equivalent system having uniform diameter \[{{d}_{1}}\] of the shaft. The equivalent length of the shaft is equal to:
  A)
  \[{{l}_{1}}+{{l}_{2}}+{{l}_{3}}\] done clear
  B)
  \[\frac{{{l}_{1}}+{{l}_{2}}+{{l}_{3}}}{3}\] done clear
  C)
  \[{{l}_{1}}+{{l}_{2}}{{\left( \frac{{{d}_{1}}}{{{d}_{2}}} \right)}^{3}}+{{l}_{3}}{{\left( \frac{{{d}_{1}}}{{{d}_{3}}} \right)}^{3}}\] done clear
  D)
  \[{{l}_{1}}+{{l}_{2}}{{\left( \frac{{{d}_{1}}}{{{d}_{2}}} \right)}^{4}}+{{l}_{3}}{{\left( \frac{{{d}_{1}}}{{{d}_{3}}} \right)}^{4}}\] done clear
  View Solution play_arrow

• question_answer24)
  If a mass 'm' oscillates on a spring having a mass   \[{{m}_{s}}\] and stiffness ?k?, then the natural frequency of the system is given by:
  A)
  \[\sqrt{\frac{k}{m+\frac{{{m}_{s}}}{3}}}\]                   done clear
  B)
  \[\sqrt{\frac{k}{\frac{m}{3}+{{m}_{s}}}}\] done clear
  C)
  \[\sqrt{\frac{3k}{m+{{m}_{s}}}}\]                    done clear
  D)
  \[\sqrt{\frac{k}{m+{{m}_{s}}}}\] done clear
  View Solution play_arrow

• question_answer25)
  Match List-I with List-II and select the correct answer using the codes given below the lists:

  List-I		List-II
  A.	Node and mode	1.	Geared vibration
  B.	Equivalent inertia	2.	Damped-free vibration
  C.	Log decrement	3.	Forced vibration
  D.	Resonance	4.	Multi-rotor  vibration

  Codes:
  A)
  A\[\to \]1, B\[\to \]4, C\[\to \]3, D\[\to \]2 done clear
  B)
  A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 done clear
  C)
  A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3 done clear
  D)
  A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2  done clear
  View Solution play_arrow

• question_answer26)
  The natural frequency of transverse vibration of a massless beam of length L having a mass m attached at its midspan is given by:       (El is the flexural rigidity of the beam)
  A)
  \[{{\left( \frac{m{{l}^{3}}}{48EI} \right)}^{\frac{1}{2}}}\text{rad/s}\]  done clear
  B)
  \[{{\left( \frac{48m{{l}^{3}}}{EI} \right)}^{\frac{1}{2}}}\text{rad/s}\] done clear
  C)
  \[{{\left( \frac{48EI}{m{{L}^{3}}} \right)}^{\frac{1}{2}}}\text{rad/s}\] done clear
  D)
  \[{{\left( \frac{3EI}{m{{L}^{3}}} \right)}^{\frac{1}{2}}}\text{rad/s}\] done clear
  View Solution play_arrow

• question_answer27)
  If a spring-mass-dashpot system is subjected to excitation by a constant harmonic force, then at resonance, its amplitude of vibration will be:
  A)
  Infinity done clear
  B)
  Inversely proportional to damping done clear
  C)
  Directly proportional to damping done clear
  D)
  Decreasing exponentially with time done clear
  View Solution play_arrow

• question_answer28)
  In a forced vibration with viscous damping, maximum amplitude occurs when forced frequency is:
  A)
  Equal to natural frequency        done clear
  B)
  Slightly less than natural frequency done clear
  C)
  Slightly greater than natural frequency done clear
  D)
  Zero done clear
  View Solution play_arrow

• question_answer29)
  The value of the natural frequency obtained by Rayleigh's method:
  A)
  Is always greater than the actual fundamental frequency done clear
  B)
  Is always less than the actual fundamental frequency done clear
  C)
  Depends upon the initial deflection curve chosen and may be greater than or less than the actual fundamental frequency done clear
  D)
  Is independent of the initial deflection curve chosen. done clear
  View Solution play_arrow

• question_answer30)
  In a multi-rotor system of torsional vibration maximum number of nodes that can occur is:
  A)
  Two done clear
  B)
  Equal to the number of rotor plus one done clear
  C)
  Equal to the number of rotors done clear
  D)
  Equal to the number of rotors minus one done clear
  View Solution play_arrow

• question_answer31)
  A rotating shaft carries a flywheel which overhangs on the bearing as a cantilever. If this flywheel weight is reduced to half of its original weight, the whirling speed will:
  A)
  Be double done clear
  B)
  Increase by \[\sqrt{2}\] times done clear
  C)
  Decrease by \[\sqrt{2}\] times done clear
  D)
  Be half done clear
  View Solution play_arrow

• question_answer32)
  The damping force in forced vibrations with reference to spring force:
  A)
  Leads by \[90{}^\circ \] done clear
  B)
  Lags by \[90{}^\circ \] done clear
  C)
  Leads by \[180{}^\circ \] done clear
  D)
  Lags by \[180{}^\circ \] done clear
  View Solution play_arrow

• question_answer33)
  Match List-I with List-II and select the correct answer using the codes given below the Lists:

  List-I		List-II
  A.	6 d.o.f. system	1.	Vibrating beam
  B.	1 d.o.f. system	2.	Vibration absorber
  C.	2 d.o.f. system	3.	A rigid body in space
  D.	Multi d.o.f. system	4.	Pure rolling of a cylinder

  Codes:
  A)
  A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]5 done clear
  B)
  A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3 done clear
  C)
  A\[\to \]3, B\[\to \]2, C\[\to \]4, D\[\to \]1 done clear
  D)
  A\[\to \]3, B\[\to \]4, C\[\to \]2, D\[\to \]1 done clear
  View Solution play_arrow

• question_answer34)
  A shaft carries a weight W at the centre. The CG of the weight is displaced by an amount e from the axis of the rotation. If 'y is the additional displacement of the CG from the axis of rotation due to the centrifugal force, then the ratio of y to e (where \[{{\omega }_{c}}\] is the critical speed of shaft and \[\omega \] is the angular speed of shaft) is given by:
  A)
  \[\frac{1}{{{\left[ \frac{{{\omega }_{c}}}{\omega } \right]}^{2}}+1}\]               done clear
  B)
  \[\frac{1}{{{\left[ \frac{{{\omega }_{c}}}{\omega } \right]}^{2}}-1}\] done clear
  C)
  \[{{\left[ \frac{{{\omega }_{c}}}{\omega } \right]}^{2}}+1\]                  done clear
  D)
  \[\frac{\omega }{{{\left[ \frac{{{\omega }_{c}}}{\omega } \right]}^{2}}-1}\] done clear
  View Solution play_arrow

• question_answer35)
  When a vehicle travels on a rough road whose undulations can be assumed to be sinusoidal, the resonant conditions of the base-excited vibrations, are determined by the:
  A)
  Mass of the vehicle, stiffness of the suspension spring, speed of the vehicle, wavelength of the roughness curve done clear
  B)
  Speed of the vehicle only done clear
  C)
  Speed of the vehicle and the stillness of the suspension spring done clear
  D)
  Amplitude of the undulations done clear
  View Solution play_arrow

• question_answer36)
   During torsional vibration of a shaft, the node is characterized by the:
  A)
  Maximum angular velocity done clear
  B)
  Maximum angular displacement done clear
  C)
  Maximum angular acceleration done clear
  D)
  Zero angular displacement done clear
  View Solution play_arrow

• question_answer37)
  A rod of uniform diameter is suspended from one of its ends in vertical plane. The mass of the rod is 'm' and length T, the natural frequency of this rod in Hz for small amplitude is:
  A)
  \[\frac{1}{2\pi }\sqrt{\frac{g}{l}}\]                      done clear
  B)
  \[\frac{1}{2\pi }\sqrt{\frac{g}{3l}}\] done clear
  C)
  \[\frac{1}{2\pi }\sqrt{\frac{2g}{3l}}\]                  done clear
  D)
  \[\frac{1}{2\pi }\sqrt{\frac{3g}{2l}}\] done clear
  View Solution play_arrow

• question_answer38)
  The mass moment of inertia of the two motors in a two rotor system arc \[100\,\,kg.{{m}^{2}}\] and \[10\,\,kg.{{m}^{2}}.\] the length of the shaft of uniform diameter between the rotors is 110 cm. The distance of node from the rotor of lower moment of inertia is:
  A)
  80 cm               done clear
  B)
  90 cm done clear
  C)
  100 cm              done clear
  D)
  110 cm done clear
  View Solution play_arrow

• question_answer39)
  A shaft of 50 mm diameter and 1 m length carries a disc which has mass eccentricity equal to 190 microns. The displacement of the shaft at a speed which is 90% of critical speed in microns is:
  A)
  810                               done clear
  B)
  900 done clear
  C)
  800                               done clear
  D)
  820 done clear
  View Solution play_arrow

• question_answer40)
  What is the number of nodes in a shalt carrying three rotors?
  A)
  Zero                              done clear
  B)
  2 done clear
  C)
  3                                  done clear
  D)
  4 done clear
  View Solution play_arrow

• question_answer41)
  \[\frac{{{\partial }^{2}}u}{\partial {{t}^{2}}}={{c}^{2}}\frac{{{\partial }^{2}}u}{\partial {{t}^{2}}}\] represents the equation for:
  A)
  Vibration of a stretched string done clear
  B)
  Motion of a projectile in a gravitational field done clear
  C)
  Heat flow in thin rod done clear
  D)
  Oscillation of a simple pendulum done clear
  View Solution play_arrow

• question_answer42)
  The natural frequency of an undamped vibrating system is 100 rad/s. A damper with a damping factor of 0.8 is introduced into the system. The frequency of vibration of the damped system, in rad/s, is:
  A)
  60                                 done clear
  B)
  75 done clear
  C)
  80                                 done clear
  D)
  100 done clear
  View Solution play_arrow

• question_answer43)
  A mass m attached to a light spring oscillates with a period of 2 sec. If the mass is increased by 2 kg, the period increases by 1 sec. The value ofwis:
  A)
  1kg                   done clear
  B)
  1.6 kg done clear
  C)
  2 kg                              done clear
  D)
  2.4 kg done clear
  View Solution play_arrow

• question_answer44)
  High damping reduces the transmissibility if the non-dimensional frequency ratio  \[\omega /{{\omega }_{n}}(\omega =forcing\,\,frequency,\,\,{{\omega }_{n}}=natural\text{ }frequency):\]
  A)
  Is less than \[\sqrt{2}\]     done clear
  B)
  is greater than \[\sqrt{2}\] done clear
  C)
  Is less than \[\frac{1}{\sqrt{2}}\]  done clear
  D)
  is greater than \[\frac{1}{\sqrt{2}}\] done clear
  View Solution play_arrow

• question_answer45)
  For lightly damped heavy rotor systems, resonance occurs when the forcing co is equal to: Where \[{{\omega }_{cr}}\] is the critical speed.
  A)
  \[2\,\,{{\omega }_{cr}}\]            done clear
  B)
  \[\sqrt{2}\,\,{{\omega }_{cr}}\] done clear
  C)
  \[{{\omega }_{cr}}\]                              done clear
  D)
  \[\frac{1}{2}\,\,{{\omega }_{cr}}\] done clear
  View Solution play_arrow

• question_answer46)
  The silencer of an internal combustion engine:
  A)
  Reduces noise done clear
  B)
  Decreases brake specific fuel consumption (BSFC) done clear
  C)
  Increases BSFC done clear
  D)
  Has no effect on its efficiency done clear
  View Solution play_arrow

• question_answer47)
  The deflection of a spring with 20 active turns under a load of 1000 N is 10 mm. The spring is made-into two pieces each of 10 active coils and placed in parallel under the same load. The deflection of this system is:
  A)
  20 mm              done clear
  B)
  10 mm         done clear
  C)
  5 mm                done clear
  D)
  2.5 mm  done clear
  View Solution play_arrow

• question_answer48)
        A flexible rotor-shaft system comprises of a 10 kg rotor disc placed in the middle of a massless shaft of diameter 30 mm and length 500 mm between bearings (shaft is being taken massless as the equivalent of the shaft, is included in the rotor mass) the ends. The bearings are assumed to simulate a supported boundary conditions. The shaft is made of steel for which the value of \[E=2.1\times {{10}^{11}}\]Pa. what is the critical speed of rotation of the shaft?
  A)
  60 Hz                done clear
  B)
  90 Hz        done clear
  C)
  135 Hz              done clear
  D)
  180 Hz  done clear
  View Solution play_arrow

• question_answer49)
       A vibrating machine is isolated from the floor using springs. If the ratio of excitation frequency of vibration of machine to the natural frequency of the isolation system is equal to 0.5, the transmissibility of ratio of isolation is: 
  A)
  \[\frac{1}{2}\]                           done clear
  B)
  \[\frac{3}{4}\] done clear
  C)
  \[\frac{4}{3}\]                           done clear
  D)
  2 done clear
  View Solution play_arrow

• question_answer50)
                   For steady flow through an insulated horizontal constant diameter pipe, this property remains constant
  A)
  Enthalpy                        done clear
  B)
  Internal energy done clear
  C)
  Entropy                         done clear
  D)
  Volume   done clear
  View Solution play_arrow

• question_answer51)
     100 kJ of energy is transferred from a heat reservoir at 1000 K to a heat reservoir at 500 K. The ambient temperature is 300 K. The loss of available energy due to heat transfer process is:           
  A)
  20 kJ                 done clear
  B)
  30 kJ done clear
  C)
  40 kJ                 done clear
  D)
  50 kJ done clear
  View Solution play_arrow

• question_answer52)
  A shaft, supported on two bearings at its ends, carries two flywheels 'L' apart. Mass moment of inertia of the two flywheels are \[{{l}_{a}}\] and \[{{l}_{b}}\] I being the polar moment of inertia of cross-sectional area of inertia of shaft. Distance \[{{l}_{a}}\] of the node of torsional vibration of the shaft from the flywheel la is \[{{l}_{a}}\] given by: 
  A)
  \[{{l}_{a}}=\frac{L{{l}_{b}}}{{{I}_{a}}+{{I}_{b}}}\]                        done clear
  B)
  \[{{l}_{a}}=\frac{L{{l}_{a}}}{{{I}_{a}}+{{I}_{b}}}\] done clear
  C)
  \[{{l}_{a}}=\frac{L{{l}_{b}}}{{{I}_{a}}+{{I}_{b}}-1}\]         done clear
  D)
  \[{{l}_{a}}=\frac{L{{l}_{a}}}{{{I}_{a}}+{{I}_{b}}-1}\]  done clear
  View Solution play_arrow

• question_answer53)
  The transmitted force through a mass-spring damper system will be greater than that transmitted through rigid supports for all values of-damping factors, if the frequency ratio \[\left( \frac{\omega }{{{\omega }_{n}}} \right)\] is:
  A)
  More than \[\sqrt{2}\]      done clear
  B)
  less than \[\sqrt{2}\] done clear
  C)
  Equal to one                  done clear
  D)
  less than one done clear
  View Solution play_arrow

• question_answer54)
  In a forced vibrations with viscous damping, maximum amplitude occurs when the forced frequency is:
  A)
  Equal to natural frequency done clear
  B)
  Slightly less than natural frequency done clear
  C)
  Slightly greater than natural frequency done clear
  D)
  Zero. done clear
  View Solution play_arrow

• question_answer55)
  The rotor of a turbine is generally rotated at:
  A)
  The critical speed done clear
  B)
  A speed much below the critical speed done clear
  C)
  A speed much above the critical speed done clear
  D)
  A speed having no relation to critical speed done clear
  View Solution play_arrow

• question_answer56)
  A reed type tachometer uses the principle of:
  A)
  Torsional vibration   done clear
  B)
  Longitudinal vibration done clear
  C)
  Transverse vibration done clear
  D)
  Damped free vibration done clear
  View Solution play_arrow

• question_answer57)
  A viscous damping system with free vibrations will be critically damped if the damping factor is:
  A)
  zero                               done clear
  B)
  less than one done clear
  C)
  Equal to one                  done clear
  D)
  greater than one done clear
  View Solution play_arrow

• question_answer58)
  In a simple spring mass vibrating system, the natural frequency \[{{\omega }_{n}}\] of the system is (k is spring stiffness m is mass and \[{{m}_{s}}\] is spring mass):
  A)
  \[\sqrt{\frac{k}{m-\frac{{{m}_{s}}}{3}}}\]                     done clear
  B)
  \[\sqrt{\frac{k}{m+\frac{{{m}_{s}}}{3}}}\] done clear
  C)
  \[\sqrt{\frac{k}{m+3{{m}_{s}}}}\]                    done clear
  D)
  \[\sqrt{\frac{k}{m-3{{m}_{s}}}}\] done clear
  View Solution play_arrow

• question_answer59)
  Consider the following methods:

  1. Energy method

  2. Equilibrium method

  3. Rayleigh's method.

  Which of these methods can be used for determining the natural frequency of the free vibrations?
  A)
  1 and 2             done clear
  B)
  1, 2 and 3 done clear
  C)
  1 and 3             done clear
  D)
  2 and 3 done clear
  View Solution play_arrow

• question_answer60)
  Consider the following statements:

  1. In forced vibrations the body vibrates under the influence of an applied force.

  2. In damped vibrations amplitude reduces over every cycle of vibration

  3. In torsional vibrations the disc moves parallel to the axis of shaft.

  4. in transverse vibrations the particles of the shaft moves approximately perpendicular to the axis of the shaft.

  Which of these statements are correct?
  A)
  1, 2 and 3                      done clear
  B)
  1, 3 and 4 done clear
  C)
  2, 3 and 4                      done clear
  D)
  1, 2 and 4 done clear
  View Solution play_arrow

• question_answer61)
  Whirling speed of shaft is the speed at which:
  A)
  Shaft tends to vibrate in longitudinal direction done clear
  B)
  Torsional vibrations occur done clear
  C)
  Shaft tends to vibrate vigorously in transverse direction done clear
  D)
  Combination of transverse and longitudinal vibration occurs. done clear
  View Solution play_arrow

• question_answer62)
  A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 Hz and 200 Hz respectively. The lowest critical speed is:
  A)
  5367 rpm                       done clear
  B)
  6000 rpm done clear
  C)
  9360 rpm                       done clear
  D)
  12000 rpm done clear
  View Solution play_arrow

• question_answer63)
  In a system subjected to damped forced vibrations, the ratio of maximum displacement to the static deflection is known as:
  A)
  Critical damping ratio done clear
  B)
  Damping factor done clear
  C)
  Logarithmic decrement done clear
  D)
  Magnification factor done clear
  View Solution play_arrow

• question_answer64)
  Consider the following statements: Two rotors mounted on a single shaft can be considered to be equivalent to a geared-shaft system having two rotors provided

  1. The kinetic energy of the equivalent system is equal to that of the original system.

  2. The strain energy of the equivalent system is equal to that of the original system.

  3. The shaft diameters of the two systems are equal.

  Which of these statements are correct?
  A)
  1, 2 and 3                      done clear
  B)
  1 and 2 done clear
  C)
  2 and 3             done clear
  D)
  1 and 3 done clear
  View Solution play_arrow

• question_answer65)
  A spring-mass suspension has a natural frequency of 40 rad/s. What is the damping ratio required if it is desired to reduce this frequency to 20 rad/s by adding a damper to it?
  A)
  \[\frac{\sqrt{3}}{2}\]                              done clear
  B)
  \[\frac{1}{2}\] done clear
  C)
  \[\frac{1}{\sqrt{2}}\]                              done clear
  D)
  \[\frac{1}{4}\] done clear
  View Solution play_arrow

• question_answer66)
  Transmissibility is unity at two points. Which one of the following is true for these two points?
  A)
  \[\frac{\omega }{{{\omega }_{n}}}\] is zero and \[\sqrt{3}\] for all values of damping done clear
  B)
  \[\frac{\omega }{{{\omega }_{n}}}\] is zero and \[\sqrt{2}\] for all values of damping done clear
  C)
  \[\frac{\omega }{{{\omega }_{n}}}\] is unity and 2 for all values of damping done clear
  D)
  \[\frac{\omega }{{{\omega }_{n}}}\] is unity and \[\sqrt{3}\] for all values of damping. done clear
  View Solution play_arrow

• question_answer67)
  Suppose two rotors with inertias \[{{l}_{1}}\] and \[{{l}_{2}}\] on shafts of Length \[{{l}_{1}}\] and \[{{l}_{2}}\] respectively, are connected by gears such that the speed of the \[{{l}_{2}}\] rotor is always G times that of the \[{{l}_{2}}\] rotor. This system may, for vibration analysis, he treated as being on one shaft (integral with \[{{i}_{1}}\]) if:
  A)
  \[{{l}_{1}}\] is changed to \[{{G}^{2}}{{I}_{1}}\] done clear
  B)
  \[{{I}_{2}}\] is changed to \[{{G}^{2}}{{I}_{2}}\] done clear
  C)
  \[{{I}_{1}}\] is changed to \[{{\text{I}}_{\text{1}}}\text{/}{{\text{G}}^{\text{2}}}\] done clear
  D)
  \[{{I}_{2}}\] is changed to \[{{\text{I}}_{2}}\text{/}{{\text{G}}^{\text{2}}}\] done clear
  View Solution play_arrow

• question_answer68)
  Two rotors A and B are connected to the two ends of a shaft of uniform diameter. The mass moment of inertia of rotor A about the axis of the shaft is four times that of B. If the length of the shaft is 1 m and C is the position of node for torsional vibrations, then what is the length of AC?
  A)
  1/5 m                done clear
  B)
  4/5 m done clear
  C)
  1/25 m              done clear
  D)
  16/25 m done clear
  View Solution play_arrow

• question_answer69)
  Which one of the following is realized by hydraulic dashpot shock absorbers?
  A)
  Viscous damping done clear
  B)
  Structural damping done clear
  C)
  Coulomb damping          done clear
  D)
  spring damping done clear
  View Solution play_arrow

• question_answer70)
  Which one of the following is the correct statement? Transmissibility is denned as the ratio of the:
  A)
  Force applied to the machine to the force transmitted to the foundation done clear
  B)
  Force transmitted to the foundation to the force applied to the machine done clear
  C)
  Force applied to the machine to the vector sum of spring forces done clear
  D)
  Damping forces to the spring forces. done clear
  View Solution play_arrow

• question_answer71)
  Which one of the following is correct for a shaft carrying two rotors at its ends?
  A)
  It has no node    done clear
  B)
  It has one node done clear
  C)
  It has two nodes done clear
  D)
  It has three nodes done clear
  View Solution play_arrow

• question_answer72)
  A shaft has two heavy rotors mounted on it. The transverse natural frequencies, considering each of the rotor separately, are 100 cycles/sec and 200 cycles/sec respectively. The lowest critical speed is:
  A)
  5367 rpm                       done clear
  B)
  6000 rpm done clear
  C)
  9360 rpm                       done clear
  D)
  12,000 rpm done clear
  View Solution play_arrow

• question_answer73)
  A shaft has an attached disc at the centre of its length. The disc has its centre of gravity located at a distance of 2 mm from the axis of the shaft. When the shaft is allowed to vibrate in its natural bow-shaded mode, it has a frequency of vibration of 10 radians second. When the shaft is rotated a 300 revolutions per minute, it will whirl with a radius of:
  A)
  2 mm                done clear
  B)
  225 mm done clear
  C)
  2.50 mm                       done clear
  D)
  3.00 mm done clear
  View Solution play_arrow

• question_answer74)
  A uniform cantilever beam undergoes transverse vibrations. The number of natural frequencies associated with the beam is:
  A)
  1                                  done clear
  B)
  10 done clear
  C)
  100                               done clear
  D)
  infinite done clear
  View Solution play_arrow

• question_answer75)
  Coulomb damping results from which one of the following?
  A)
  Dry friction between moving parts done clear
  B)
  Drag between a moving body and the fluid environment done clear
  C)
  Internal friction within a material done clear
  D)
  Radiation of energy into the environmentl. done clear
  View Solution play_arrow

• question_answer76)
  Consider the following statements:        

  1. When frequency ratio is < 2, the force transmitted to the foundation is more than the exciting force.

  2. When frequency ratio is > 2, the force transmitted to the foundation increases and the damping is decreased.

  3. The analysis of base excited vibrations is similar to that of forced vibrations.

  Which of these statements are correct?    
  A)
  1 and 2             done clear
  B)
  2 and 5 done clear
  C)
  1 and 3             done clear
  D)
  1, 2 and 3 done clear
  View Solution play_arrow

• question_answer77)
  Consider the following statements:        

  1. Critical or whirling speed of the shaft is the speed at which it tends to vibrate violently in the transverse direction.

  2. To find the natural frequency of a shaft carrying several loads, the energy method gives approximate results.

  3. Dunkerley's method gives accurate results of the natural frequency of a shaft carrying several loads.

  Which of these statements is/are correct? 
  A)
  1 only               done clear
  B)
  2 and 3 done clear
  C)
  1 and 3             done clear
  D)
  1, 2 and 3   done clear
  View Solution play_arrow

• question_answer78)
  For a single degree of freedom damped system, transmissibility is less than 1 if frequency ratio is:
  A)
  \[Equal\,\,to\,\,1\]                        done clear
  B)
  <1 done clear
  C)
  \[<\sqrt{2}\]                  done clear
  D)
  \[>\sqrt{2}\] done clear
  View Solution play_arrow

• question_answer79)
  For a harmonically excited single degree of freedom viscous damped system, which one of the following is correct?
  A)
  Inertia force leads damping force by \[90{}^\circ \] while damping force leads spring force by\[90{}^\circ \]. done clear
  B)
  Spring force leads damping force by \[90{}^\circ \] while damping force leads inertia force by\[180{}^\circ \]. done clear
  C)
  Spring force and damping force are in phase, and inertia force leads them by \[90{}^\circ \] done clear
  D)
  Spring force and inertia force are in phase, and damping force leads them by \[90{}^\circ \] done clear
  View Solution play_arrow

• question_answer80)
  In a viscously damped vibratory system with harmonic excitation, if \[{{\omega }_{1}}\] and \[{{\omega }_{2}}\] are the half power points, \[{{\omega }_{n}}\] is the natural frequency and \[\zeta \] is the damping factor, which one of the following is correct? 
  A)
  \[\frac{{{\omega }_{2}}-{{\omega }_{1}}}{{{\omega }_{n}}}\]              done clear
  B)
  \[\frac{{{\omega }_{2}}+{{\omega }_{1}}}{{{\omega }_{n}}}=\zeta \] done clear
  C)
  \[\frac{{{\omega }_{2}}-{{\omega }_{1}}}{{{\omega }_{n}}}={{\zeta }^{2}}\]            done clear
  D)
  \[\frac{{{\omega }_{2}}-{{\omega }_{1}}}{{{\omega }_{n}}}=\zeta \] done clear
  View Solution play_arrow

• question_answer81)
  Match List-I with List-II regarding a body party submerged in a liquid and select the correct answer using the codes given below the lists:

  List-I		List-II
  A.	Centre of pressure	1.	Point of application of the weight of displaced liquid
  B.	Centre of gravity	2.	Point about which the body starts oscillating when tilted by a small angle
  C.	Centre of buoyancy	3.	Point of application of hydrostatic pressure
  D.	Metacentre	4.	Point of application of the weight of the body

  Codes:
  A)
  A\[\to \]4, B\[\to \]3, C\[\to \]1, D\[\to \]2 done clear
  B)
  A\[\to \]4, B\[\to \]3, C\[\to \]2, D\[\to \]1 done clear
  C)
  A\[\to \]3, B\[\to \]4, C\[\to \]1, D\[\to \]2 done clear
  D)
  A\[\to \]3, B\[\to \]4, C\[\to \]2, D\[\to \]1 done clear
  View Solution play_arrow

• question_answer82)
  If a piece of metal having a specific gravity of 13.6 is placed in mercury of specific gravity 13.6, then:
  A)
  The metal piece will sink to the bottom done clear
  B)
  The metal piece will simply float over the mercury with no immersion done clear
  C)
  The metal piece will be immersed in mercury by half done clear
  D)
  The whole of the metal piece will be immersed with its top surface just at mercury level done clear
  View Solution play_arrow

• question_answer83)
  A bucket of water hangs with a spring balance. If an iron piece is suspended into water from another support without touching the sides of the bucket, the spring balance will show:
  A)
  An increased reading done clear
  B)
  A decreased reading done clear
  C)
  No change in reading done clear
  D)
  Increased or decreased reading depending on the depth of immersion done clear
  View Solution play_arrow

• question_answer84)
  The least radius of gyration of a ship is 9 m and the metacentric height is 750 mm. The time period of oscillation of the ship is:
  A)
  42.41 s              done clear
  B)
  75.4 s done clear
  C)
  20.85 s              done clear
  D)
  85 s done clear
  View Solution play_arrow

• question_answer85)
  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)
  \[0.146\,\,\text{N/}{{\text{m}}^{\text{2}}}\]                 done clear
  B)
  \[0.73\,\,\text{N/}{{\text{m}}^{\text{2}}}\] done clear
  C)
  \[146\,\,\text{N/}{{\text{m}}^{\text{2}}}\]                    done clear
  D)
  \[292\,\,\text{N/}{{\text{m}}^{\text{2}}}\] done clear
  View Solution play_arrow

• question_answer86)
  Newton's law of viscosity depends upon the:
  A)
  Stress and strain in a fluid done clear
  B)
  Shear stress, pressure and velocity done clear
  C)
  Shear stress and rate of strain done clear
  D)
  Viscosity and shear stress done clear
  View Solution play_arrow

• question_answer87)
  The critical speed of a uniform shaft with a rotor at the centre of the span can be reduced by:
  A)
  Reducing the shaft length done clear
  B)
  Reducing the rotor mass done clear
  C)
  Increasing the rotor mass done clear
  D)
  Increasing the shaft diameter done clear
  View Solution play_arrow

• question_answer88)
  Match List-I (Surfaces with Orientations) with List-II (Equivalent Emissivity) and select the correct answer using the codes given below the lists:

  List I (Surfaces with orientations)		List-II (Equivalent Emissivity)
  A.	Infinite parallel planes	1.	\[{{\in }_{1}}\]
  B.	Body 1 completely enclosed by body 2 but body 1 is very small	2.	\[\frac{1}{\frac{1}{{{\in }_{1}}}+\frac{1}{{{\in }_{2}}}-1}\]
  C.	Radiation exchange between two small gray bodies	3.	\[\frac{1}{\frac{1}{{{\in }_{1}}}+\left( \frac{{{A}_{1}}}{{{A}_{2}}} \right)\left( \frac{1}{{{\in }_{2}}}-1 \right)}\]
  D.	Two concentric cylinders with large lengths	4.	\[{{\in }_{1}}.{{\in }_{2}}\]

  Codes:
  A)
  A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]2 done clear
  B)
  A\[\to \]2, B\[\to \]4, C\[\to \]1, D\[\to \]3 done clear
  C)
  A\[\to \]2, B\[\to \]1, C\[\to \]4, D\[\to \]3 done clear
  D)
  A\[\to \]3, B\[\to \]4, C\[\to \]1, D\[\to \]2 done clear
  View Solution play_arrow

• question_answer89)
  Two spheres A and B of same material have radii 1 m and 4 m and temperature 4000 K and 2000 K respectively. Which one of the following statements is correct? The energy radiated by sphere A is:
  A)
  Greater than that of sphere B done clear
  B)
  Less than that of sphere B done clear
  C)
  Equal to that of sphere B done clear
  D)
  Equal to double that of sphere B done clear
  View Solution play_arrow

• question_answer90)
  For an opaque plane surface, the irradiation, radiosity and emissive power are respectively 20, 12 and \[10\,\,\text{W/}{{\text{m}}^{\text{2}}}.\] what is the emissivity of the surface?
  A)
  0.2                                done clear
  B)
  0.4 done clear
  C)
  0.8                                done clear
  D)
  1.0 done clear
  View Solution play_arrow

• question_answer91)
  Two long parallel surfaces, each of emissivity 0.7, are maintained at different temperatures and accordingly have radiation exchange between them. It is desired to reduce 75% of this radiant heat transfer by inserting thin parallel shields of equal emissivity (0.7) on both sides. What would be the number of shields?
  A)
  1                                  done clear
  B)
  2 done clear
  C)
  3                                  done clear
  D)
  4 done clear
  View Solution play_arrow

• question_answer92)
  The earth receives at its surface radiation from the sun at the rate of \[1400\,\,\text{W/}{{\text{m}}^{\text{2}}}.\] the distance of centre of sun from the surface of earth is \[1.5\times {{10}^{11}}m\] and the radius of sun is \[7.0\times {{10}^{8}}M.\] what is approximately the surface temperature of the sun treating the sun as a black body?
  A)
  3650 K              done clear
  B)
  4500 K done clear
  C)
  5800 K              done clear
  D)
  6150 K done clear
  View Solution play_arrow

• question_answer93)
  A composite plane wall is made up of two different materials of the same thickness and having thermal conductivities of \[{{k}_{1}}\] and \[{{k}_{2}}\] respectively. The equivalent thermal conductivity of the slab is:
  A)
  \[{{k}_{1}}+{{k}_{2}}\]                      done clear
  B)
  \[{{k}_{1}}{{k}_{2}}\] done clear
  C)
  \[\frac{{{k}_{1}}+{{k}_{2}}}{{{k}_{1}}{{k}_{2}}}\]              done clear
  D)
  \[\frac{2{{k}_{1}}{{k}_{2}}}{{{k}_{1}}+{{k}_{2}}}\] done clear
  View Solution play_arrow

• question_answer94)
  A copper wire of radius 0.5 mm is insulated with a sheathing of thickness 1 mm having a thermo- conductivity of 05 W/m.K. The outside surface convective heat transfer coefficient is 10 W/m.K. If the thickness of insulation sheathing is raised by 10 mm, then the electrical current carrying capacity of the wire will:
  A)
  Increase done clear
  B)
  Decrease done clear
  C)
  Remain the same done clear
  D)
  Vary depending upon the electric conductivity of the wire. done clear
  View Solution play_arrow

• question_answer95)
  For the fully developed laminar flow and the transfer in a uniformly heated long circular tube, if the velocity is doubled and the tube diameter is halved, the heat transfer coefficient will be:
  A)
  Double of the original value done clear
  B)
  Half of the original value done clear
  C)
  Same as before done clear
  D)
  Four times of the original value. done clear
  View Solution play_arrow

• question_answer96)
  For an air conditioning plant above 300 ton, which one of the following system would normally he preferred?
  A)
  Ammonia reciprocating compressor done clear
  B)
  Centrifugal Chiller done clear
  C)
  Absorption refrigeration system done clear
  D)
  Hermetic compressor done clear
  View Solution play_arrow

• question_answer97)
  Fresh air intake (air change per hour) recommended for ventilation purposes in the air conditioning system of an office building is:
  A)
  1/2                                done clear
  B)
  3/2 done clear
  C)
  9/2                                done clear
  D)
  25/2 done clear
  View Solution play_arrow

• question_answer98)
  Air refrigeration cycle is used in:
  A)
  Commercial refrigerators done clear
  B)
  Domestic refrigerators done clear
  C)
  Gas liquefaction done clear
  D)
  Air-conditioning done clear
  View Solution play_arrow

• question_answer99)
  The flash chamber in a single stage simple vapour compression cycle:
  A)
  Increase the refrigerating effect done clear
  B)
  Decreases the refrigerating effect         done clear
  C)
  Increases the work of compression      done clear
  D)
  Has no effect on refrigerating effect    done clear
  View Solution play_arrow

• question_answer100)
  Consider the following statements:      

  In a vapour compression system, a thermometer placed in the liquid line can indicate whether the:

  1. Refrigerant flow is too low

  2. Water circulation is adequate.

  3. Condenser is fouled.

  4. Pump is functioning properly.

  Of these statement:                      
  A)
  1, 2 and 3 are correct done clear
  B)
  1, 2 and 4 are correct done clear
  C)
  1, 3 and 4 are correct done clear
  D)
  2, 3 and 4 are correct done clear
  View Solution play_arrow

• question_answer101)
  Match List-I with List-II and select the correct answer using the codes given below the Lists. 

  List-I		List-II
  A.	Bell Column refrigeration	1.	Compressor
  B.	Vapour compression refrigeration	2.	Generator
  C.	Absorption refrigeration	3.	Flash chamber
  D.	Jet refrigeration	4.	Expansion cylinder

  Codes:
  A)
  A\[\to \]1, B\[\to \]4, C\[\to \]3, D\[\to \]2 done clear
  B)
  A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2 done clear
  C)
  A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3 done clear
  D)
  A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3 done clear
  View Solution play_arrow

• question_answer102)
  The maximum COP for the absorption cycle is given by\[({{T}_{c}}=generator\,\,temperature\,\,{{T}_{c}}=environment\,\,temperature,\]\[{{T}_{E}}=refrigerated\,\,space\,\,temperature)\]
  A)
  \[\frac{{{T}_{E}}({{T}_{G}}-{{T}_{C}})}{{{T}_{G}}({{T}_{C}}-{{T}_{E}})}\]                      done clear
  B)
  \[\frac{{{T}_{G}}({{T}_{C}}-{{T}_{E}})}{{{T}_{E}}({{T}_{G}}-{{T}_{C}})}\] done clear
  C)
  \[\frac{{{T}_{C}}({{T}_{G}}-{{T}_{E}})}{{{T}_{G}}({{T}_{C}}-{{T}_{E}})}\]                      done clear
  D)
  \[\frac{{{T}_{G}}({{T}_{C}}-{{T}_{E}})}{{{T}_{C}}({{T}_{G}}-{{T}_{E}})}\] done clear
  View Solution play_arrow

• question_answer103)
  In milk chilling plants, the usual secondary refrigerant is:                                     
  A)
  Ammonia solution           done clear
  B)
  Sodium Silicate done clear
  C)
  Glycol               done clear
  D)
  Brine done clear
  View Solution play_arrow

• question_answer104)
        104. The desirable combination of properties of a refrigerant include :                  
  A)
  High specific heat and low specific volume done clear
  B)
  High heat transfer coefficient and low latent heat                              done clear
  C)
  High thermal conductivity and low specific volume done clear
  D)
  High specific heat and high boiling point. done clear
  View Solution play_arrow

• question_answer105)
  Which of the following method(s) is/are adopted in the design of air duct system           

  1. Velocity reduction method

  2. Equal friction method

  3. Static regain method.

  Select the correct answer using the codes given below: Codes:
  A)
  1 alone              done clear
  B)
  1 and 2 done clear
  C)
  2 and 3             done clear
  D)
  1, 2 and 3 done clear
  View Solution play_arrow

• question_answer106)
  To fix the stale point in respect of air-vapour mixtures, three intrinsic properties are needed. Yet, the psychrometric chart requires only two because:
  A)
  Water vapour is in the superheated state done clear
  B)
  The chart is for a given pressure done clear
  C)
  The chart is an approximation to true values done clear
  D)
  The mixtures can be treated as a perfect gas done clear
  View Solution play_arrow

• question_answer107)
  During sensible cooling of air :
  A)
  Its wet bulb temperature increases and dew point remains constant done clear
  B)
  Its wet bulb temperature decreases and the dew point remains constant done clear
  C)
  Its wet bulb temperature increases and the dew point decreases done clear
  D)
  It wet bulb temperature decreases and dew point increases. done clear
  View Solution play_arrow

• question_answer108)
  The expression \[\frac{0.622{{p}_{v}}}{{{p}_{r}}-{{p}_{v}}}\] is used to determine:
  A)
  Relative humidity   done clear
  B)
  Specific humidity done clear
  C)
  Degree of saturation done clear
  D)
  Partial pressure done clear
  View Solution play_arrow

• question_answer109)
  The effective temperature is a measure of the combined effects of:
  A)
  Dry bulb temperature and relative humidity done clear
  B)
  Dry bulb temperature and air motion done clear
  C)
  Wet bulb temperature and air motion done clear
  D)
  Dry bulb temperature, relative humidity and air motion. done clear
  View Solution play_arrow

• question_answer110)
  In air-conditioning design for summer months, the condition inside a factory where heavy work in performed as compared to a factory in which light work is performed should have:
  A)
  Lower dry bulb temperature and lower relative humidity done clear
  B)
  Lower dry bulb temperature and higher relative humidity done clear
  C)
  Lower dry bulb temperature and same relative humidity done clear
  D)
  Same dry bulb temperature and same relative humidity. done clear
  View Solution play_arrow

• question_answer111)
  For low by pass factor a cooling coil, the fin spacing and the number of tube rows will be respectively:
  A)
  High and high     done clear
  B)
  High and low done clear
  C)
  Low and high     done clear
  D)
  Low and low done clear
  View Solution play_arrow

• question_answer112)
  In vapour compression plant, if certain temperature differences are to be maintained in the evaporator and condenser in order to obtain the necessary heat transfer, then the evaporator saturation temperature must be:
  A)
  Higher than the derived cold-region temperature and the condenser saturation temperature must be lower than the available cooling water temperature by sufficient amounts done clear
  B)
  Low than the derived cold-region temperature and the condenser saturation temperature must be lower than the available cooling water temperature by sufficient amounts done clear
  C)
  Lower than the derived cold-region temperature and the condenser saturation temperature must be higher than the available cooling water temperature by sufficient amounts done clear
  D)
  Higher than the derived cold-region temperature and the condenser saturation temperature must he higher than the available cooling water temperature by sufficient amounts. done clear
  View Solution play_arrow

• question_answer113)
  One ton refrigeration is equivalent to:
  A)
  3.5 kW              done clear
  B)
  50 kJ/s done clear
  C)
  1000 J/min                    done clear
  D)
  1000 kJ/min done clear
  View Solution play_arrow

• question_answer114)
  The correct sequence of the given components of a vapour compression refrigerator is:
  A)
  Evaporator, compressor, condenser and throttle valve done clear
  B)
  Condenser, throttle valve, evaporator and compressor done clear
  C)
  Compressor, condenser, throttle valve and evaporator done clear
  D)
  Throttle valve, evaporator, compressor and condenser done clear
  View Solution play_arrow

• question_answer115)
  The coefficient of performance of a refrigerator working on a reversed Carnot cycle is 4 the ratio of the highest absolute temperature to the lowest absolute temperature is:
  A)
  1.2                                done clear
  B)
  1.25 done clear
  C)
  3.33                              done clear
  D)
  4 done clear
  View Solution play_arrow

• question_answer116)
  When a burnt out hermetic compressor is replaced by a new one it is desirable to include in the system a large drier-cum-strainer also. This is to be placed in:
  A)
  Liquid line                      done clear
  B)
  Suction line done clear
  C)
  Hot gas line                    done clear
  D)
  Discharge line done clear
  View Solution play_arrow

• question_answer117)
  A good refrigerant should have:
  A)
  Large latent heat of vaporization and low operating pressures done clear
  B)
  Small latent heat of vaporization and high operating pressures done clear
  C)
  Large latent heat of vaporization and large operating pressures done clear
  D)
  Small latent heat of vaporization and low operating pressures done clear
  View Solution play_arrow

• question_answer118)
  The most common type of absorption system in use in industrial applications is based on the refrigerant absorbent combination of:
  A)
  Air-Water done clear
  B)
  Lithium bromide-air done clear
  C)
  Carbon dioxide-Water done clear
  D)
  Ammonia-Water done clear
  View Solution play_arrow

• question_answer119)
  Solar energy be directly used in:
  A)
  Vapour compression refrigeration system done clear
  B)
  Vapour absorption refrigeration system done clear
  C)
  Air refrigeration system done clear
  D)
  Jet refrigeration system done clear
  View Solution play_arrow

• question_answer120)
  The equation \[\phi =\frac{{{p}_{v}}}{ps}\] is used to calculate the \[({{p}_{v}}=\] partial pressure of water vapour in moist air at a given temperature \[{{p}_{s}}=\] saturation pressure of water vapour at the same temperature)
  A)
  Relative humidity done clear
  B)
  Degree of saturation done clear
  C)
  Specific humidity done clear
  D)
  Absolute humidity done clear
  View Solution play_arrow