McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 51. |
that is developed in the pipe? |
| A. | entry |
| B. | exit |
| C. | connection between two pipes |
| D. | liquid velocity |
| Answer» D. liquid velocity | |
| Explanation: liquid velocity in the pipe is the velocity with which the liquid travels through different cross sections of the pipe. it is a vector field which is used to describe the motion of a continuum. the length of flow velocity vector is equal to the flow speed. | |
| 52. |
Which among the following is the correct formula for head loss? |
| A. | z1-z2 |
| B. | c |
| C. | t2-t1 |
| D. | s2-s1 |
| Answer» A. z1-z2 | |
| Explanation: total head loss for a system is equal to the height difference of the reservoirs. height difference is denoted by the letter ‘h’. total head loss can be equated | |
| 53. |
If the two reservoirs are kept at the same level, the head loss is |
| A. | z1-z2 |
| B. | zero |
| C. | t2-t1 |
| D. | s2-s1 |
| Answer» B. zero | |
| Explanation: total head loss for a system is equal to the height difference of the reservoirs. height difference is denoted by the letter ‘h’. the height difference between the reservoirs is z1-z2. since they are of the same level, z1=z2. therefore, head loss is zero. | |
| 54. |
How do we determine the total discharge through parallel pipes? |
| A. | add them. |
| B. | subtract them |
| C. | multiply them |
| D. | divide them |
| Answer» A. add them. | |
| Explanation: total discharge in parallel pipes are determined by adding the discharges so developed in individual pipes. if q1 is the discharge through pipe 1 and q2 is the discharge through pipe 2. then the total discharge through parallel pipes is equal to | |
| 55. |
The pipe diameter is |
| A. | directly proportional to fluid density |
| B. | directly proportional to mass flow rate |
| C. | inversely proportional to mass flow rate |
| D. | directly proportional to fluid velocity |
| Answer» B. directly proportional to mass flow rate | |
| Explanation: the pipe diameter is directly | |
| 56. |
Define Viscosity. |
| A. | resistance to flow of object |
| B. | resistance to flow of air |
| C. | resistance to flow of fluid |
| D. | resistance to flow of heat |
| Answer» C. resistance to flow of fluid | |
| Explanation: viscosity is developed due to the relative motion between two surfaces of fluids at different velocities. it happens due to the shear stress developed on the surface of the fluid. | |
| 57. |
Coefficient of friction of a laminar flow is |
| A. | re/16 |
| B. | re/64 |
| C. | 16/re |
| D. | 64/re |
| Answer» C. 16/re | |
| Explanation: coefficient of friction is defined as the value that shows relationship between force and the normal reaction. it is mainly used to find out an object’s normal force and frictional force. thus, it is equal to 16/re. | |
| 58. |
TOPIC 3.1 NEED FOR DIMENSIONAL ANALYSIS - METHODS OF DIMENSIONAL ANALYSIS |
| A. | botanical science |
| B. | zoological science |
| C. | chemistry |
| D. | physics |
| Answer» C. chemistry | |
| Explanation: chemistry is the science that deals with every substance, its structure, its composition and changes. physics is the study of the natural world, matter, energy and radiation, while biology is the science that deals with the behaviour of living things are called biological sciences. | |
| 59. |
Quantum physics deals with macroscopic phenomena. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: classical physics deals with macroscopic phenomena which may be at the laboratory, terrestrial and astronomical. | |
| 60. |
Which of the following uses electromagnetic waves? |
| A. | radio |
| B. | radiotherapy |
| C. | detecting fractures |
| D. | electric motors |
| Answer» A. radio | |
| Explanation: electromagnetic waves are used in the radio. while radiotherapy and detecting fractures are done by x-rays and electric motor comes under the electric appliance. | |
| 61. |
Which is the universal attractive force? |
| A. | electromagnetic force |
| B. | strong nuclear force |
| C. | weak nuclear force |
| D. | gravitational force |
| Answer» D. gravitational force | |
| Explanation: gravitational force is the force | |
| 62. |
Gravitational force is the weakest force in nature. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: gravitational force is the weakest force in nature because it cannot be felt by us on daily basis. electromagnetic force is the strongest force in nature. | |
| 63. |
Which of the following is an example of electromagnetic force? |
| A. | motion of moon around earth |
| B. | evolution of stars |
| C. | evolution of galaxies |
| D. | compression of spring |
| Answer» D. compression of spring | |
| Explanation: when a spring is compressed, it exerts a force of elasticity due to the net repulsion/ attraction between the | |
| 64. |
Why is climbing a lamp post harder than climbing up a tree? |
| A. | because of parallel friction force |
| B. | because of contact force between the bodies |
| C. | because of van der wall’s force |
| D. | because of rope force |
| Answer» A. because of parallel friction force | |
| Explanation: sometimes, the electromagnetic contact force between two bodies may have a component acting parallel to the surface of contact. this is called friction. when bodies are placed with their smooth surfaces in contact, they provide only a small parallel component of contact of force and hence | |
| 65. |
Gravitational force, despite being a weak force, governs the large scale motion. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: mass is only of one type. so the gravitational force is always attractive. | |
| 66. |
When a body is falling freely under gravity, the total mechanical energy remains constant because of which of the following? |
| A. | law of conservation of energy |
| B. | unification of force |
| C. | electromagnetic force |
| D. | gravity |
| Answer» A. law of conservation of energy | |
| Explanation: according to the law of conservation of energy, energy can neither be created nor can it be destroyed but it can be changed from one form to another. when a body falls freely, under gravity, its potential energy gradually changes into kinetic energy. but its total mechanical energy remains constant at any point of its motion. | |
| 67. |
What happens when a bullet is fired from a rifle? |
| A. | the rifle becomes weightless |
| B. | we fall back |
| C. | rifle gives backward kick |
| D. | bullet doesn’t leave the rifle |
| Answer» C. rifle gives backward kick | |
| Explanation: a rifle gives a backward kick on firing a bullet. before firing, both the | |
| 68. |
Similitude is a concept applicable to the testing of |
| A. | mathematical models |
| B. | physical models |
| C. | engineering models |
| D. | chemical models |
| Answer» C. engineering models | |
| Explanation: similitude is an essential concept that is applicable to the testing of basic engineering models. a model has a similitude with a real-time application. it shares the same geometry. similarity and similitude are interchangeable at times. | |
| 69. |
Which among the following is the main application for Similitude? |
| A. | ships |
| B. | cars |
| C. | hydraulics |
| D. | train |
| Answer» C. hydraulics | |
| Explanation: similitude plays an important role in various applications. one of the major applications are hydraulics and aerospace engineering. its main purpose is to test the fluid flow at different conditions of scaled model. | |
| 70. |
A model of with same shape is |
| A. | geometric similarity |
| B. | kinematic similarity |
| C. | dynamic similarity |
| D. | conditional similarity |
| Answer» A. geometric similarity | |
| Explanation: geometric similarity is a similarity that follows a real-time application. it is model that has the same shape for any sort of application. it is measured in scaled quantities. | |
| 71. |
Which among the following have similar fluid streamlines? |
| A. | geometric similarity |
| B. | kinematic similarity |
| C. | dynamic similarity |
| D. | conditional similarity |
| Answer» B. kinematic similarity | |
| Explanation: in kinematic similarity, fluid flow of model and real-time application takes place. here, the model and the real application must undergo similar time rates in motion changes. thus, it has similar fluid streamlines. | |
| 72. |
Which among the following have the same forces acting on them? |
| A. | geometric similarity |
| B. | kinematic similarity |
| C. | dynamic similarity |
| D. | conditional similarity |
| Answer» C. dynamic similarity | |
| Explanation: dynamic similarities have the same forces acting on them. that means, the ratios of all the forces acting on the fluid particles are constant. also, the ratio of the | |
| 73. |
All the parameters in a similitude are described using |
| A. | continuum mechanics |
| B. | solid mechanics |
| C. | diesel mechanics |
| D. | aircraft mechanics |
| Answer» A. continuum mechanics | |
| Explanation: a branch of mechanics that deals with the analysis of mechanical behaviour of materials and kinematics of materials. they are used for modelling purposes. it is modelled in continuous mass. | |
| 74. |
Physical similitude has exactly the same geometric shape of the prototype. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: physical similitude is also called the similitude of shape. it is for modelling the same geometric shape as that of its prototype. which means, that the shape will have to be divided by a scale factor. | |
| 75. |
Which among the following is a standard scale for a similitude? |
| A. | 1:250 |
| B. | 1:50 |
| C. | 1:25 |
| D. | 1:100 |
| Answer» C. 1:25 | |
| Explanation: to design a similitude with a specific dimension, we must fix a scale. the standard system has fixed the scale as 1:25. this was fixed for an uniformity in dimensions. | |
| 76. |
In similitude, Fapplication=Fmodel*3.44 |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: a model test was conducted to determine this relation. the force and velocity that were measured in the model are to be scaled. this helps to find the force that can be expected for a real-time application. | |
| 77. |
spread is called |
| A. | surface tension |
| B. | diffusivity |
| C. | viscosity |
| D. | kinetics |
| Answer» B. diffusivity | |
| Explanation: diffusivity is defined as the | |
| 78. |
Which among the following is the standard symbol for Archimedes number? |
| A. | a |
| B. | ar |
| C. | ar |
| D. | a |
| Answer» C. ar | |
| Explanation: the standard symbol for archimedes number is ar. archimedes number in fluid mechanics deals with the motion of fluids. this takes place due to the differences in their densities. it was followed by the archimedes principle. | |
| 79. |
symbol for Atwood number? |
| A. | a |
| B. | ar |
| C. | ar |
| D. | a |
| Answer» A. a | |
| Explanation: the standard symbol for atwood number is a. atwood’s number in fluid mechanics deals with the onset of instabilities in mixtures of fluid. it is due to the density differences in fluid. | |
| 80. |
Which among the following is the standard symbol for Blake number? |
| A. | bi |
| B. | ba |
| C. | bl |
| D. | b |
| Answer» B. ba | |
| Explanation: the standard symbol for blake number is b or bl. blake number in fluid mechanics deals with geology, fluid mechanics and porous media. it is due to the inertial over the viscous forces in fluid flow through porous media. | |
| 81. |
Which among the following is the standard symbol for Darcy friction factor? |
| A. | f |
| B. | fd |
| C. | c |
| D. | cd |
| Answer» B. fd | |
| Explanation: the standard symbol for darcy friction factor is fd. darcy friction factor in fluid mechanics deals with fractions of pressure losses. this is due to the development of friction in the pipe. | |
| 82. |
Fanning friction factor is |
| A. | 0.25 times darcy friction factor |
| B. | same as darcy friction factor |
| C. | 2 times darcy friction factor |
| D. | independent |
| Answer» A. 0.25 times darcy friction factor | |
| Explanation: fanning friction factor is 0.25 times darcy friction factor. fanning friction factor in fluid mechanics deals fraction of pressure losses due to friction in the pipe. | |
| 83. |
symbol for Froude number? |
| A. | f |
| B. | fo |
| C. | fr |
| D. | f |
| Answer» C. fr | |
| Explanation: the standard symbol for froude number is fr. froude number in fluid mechanics deals with wave and surface behaviour of fluid particles. this is with the ratio of body’s inertia to gravitational forces. | |
| 84. |
Which among the following is the formula for Knudsen number? |
| A. | λ⁄l |
| B. | λ⁄2l |
| C. | λ⁄3l |
| D. | λ⁄4l |
| Answer» A. λ⁄l | |
| Explanation: the formula for knudsen number is λ⁄l. knudsen number in fluid mechanics deals with gas dynamics. it is defined as the ratio of the molecular mean free path length to the representative scale length. | |
| 85. |
utilization of |
| A. | accelerating mass |
| B. | volume |
| C. | work |
| D. | velocity |
| Answer» C. work | |
| Explanation: the principle of fluid mechanics works on the utilization of useful work. the working is based on the force exerted by a fluid jet striking the surface and moving over a series of vanes about its axis. | |
| 86. |
fluid mechanics deals with heat transfer. It is |
| A. | backward direction |
| B. | forward direction |
| C. | perpendicular direction |
| D. | parallel movement |
| Answer» B. forward direction | |
| Explanation: force exerted by a jet on a moving plate happens in three cases. the three cases are classified depending on their | |
| 87. |
The force analysis on a curved vane is understood using |
| A. | velocity triangles |
| B. | angle of the plate |
| C. | vane angles |
| D. | plate dimensions |
| Answer» A. velocity triangles | |
| Explanation: the force analysis on a curved vane is understood using clearly using the study of velocity triangles. there are two types of velocity triangles, inlet velocity triangle and outlet velocity triangle. | |
| 88. |
Jet propulsion works on the principle of |
| A. | newton’s first law |
| B. | newton’s second law |
| C. | newton’s third law |
| D. | thermodynamic properties |
| Answer» C. newton’s third law | |
| Explanation: jet propulsion works on the principle of newton’s third law. newton’s third law states that for every action, there is an equal and opposite reaction. thus, the correct option is newton’s third law. | |
| 89. |
How is absolute velocity at inlet denoted? |
| A. | v |
| B. | v1 |
| C. | c |
| D. | v |
| Answer» B. v1 | |
| Explanation: in a jet propulsion, v1 stands for absolute velocity at the inlet. the main | |
| 90. |
The relative velocity is obtained by the equation |
| A. | u – v1 |
| B. | v1 |
| C. | u*v1 |
| D. | u/v1 |
| Answer» A. u – v1 | |
| Explanation: the relative velocity of the jet is denoted as vr1. it is the relative velocity at the inlet to the vane. relative velocity of inlet to the vane is obtained by subtracting vectorially the velocity of the vane with its absolute velocity. | |
| 91. |
If the friction is neglected, then |
| A. | vr1 > vr2 |
| B. | vr1 < vr2 |
| C. | vr1 = vr2 |
| D. | vr1 is a zero |
| Answer» C. vr1 = vr2 | |
| Explanation: the relative velocity of the jet is denoted as vr1. it is the relative velocity at the inlet to the vane. relative velocity of inlet to the vane is obtained by subtracting vectorially the velocity of the vane with its absolute velocity. it happens in the same way for vr2. thus, if the friction is neglected, then vr1 = vr2. | |
| 92. |
If the pressure remains a constant, then |
| A. | vr1 > vr2 |
| B. | vr1 < vr2 |
| C. | vr1 = vr2 |
| D. | vr1 is a zero |
| Answer» C. vr1 = vr2 | |
| Explanation: the relative velocity of the jet is denoted as vr1. it is the relative velocity at | |
| 93. |
from the sea can be taken by the pump. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: through inlet orifices, which are facing the direction of motion of the ship, the water from the sea can be taken by the pump. we can also take the sea water from the pump when the inlet orifices are at right angles with respect to the motion of the ship. | |
| 94. |
Jet propulsion of ship is less efficient than screw propeller due to |
| A. | pressure |
| B. | temperature |
| C. | frictional losses |
| D. | wear and tear |
| Answer» C. frictional losses | |
| Explanation: jet propulsion of ship is less efficient than screw propeller due to large amount of frictional losses developed in the pump and the pipeline. thus, it is rarely used in ships. | |
| 95. |
A jet strikes a curved plate at its |
| A. | sides |
| B. | surface |
| C. | centre |
| D. | does not strike |
| Answer» C. centre | |
| Explanation: a jet strikes a curved plate at its centre. force exerted by a jet on a stationery plate happens in three cases. the | |
| 96. |
of jet engine? |
| A. | turbojet |
| B. | ramjet |
| C. | scramjet |
| D. | propulsive jet |
| Answer» D. propulsive jet | |
| Explanation: a jet engine is broadly classified into four types of jet. the four types of jet are turbojet, ramjet, scramjet, and pulse jet. there isn’t anything related to the propulsive jet and thus cannot be the answer. | |
| 97. |
decelerates the flow, what increases? |
| A. | pressure |
| B. | temperature |
| C. | volume |
| D. | flow rate |
| Answer» A. pressure | |
| Explanation: when the casing in a centrifugal pump decelerates the flow, pressure in the turbine increases. the diffuser helps this happen. the shape of the diffuser passing present in the centrifugal pump is doughnut shaped. | |
| 98. |
while passing |
| A. | pressure energy |
| B. | kinetic energy |
| C. | momentum |
| D. | potential energy |
| Answer» A. pressure energy | |
| Explanation: the velocity imparted by the impeller is converted into pressure energy. it | |
| 99. |
The consequence of Newtons second law is |
| A. | conservation of angular momentum |
| B. | conservation of mass |
| C. | conservation of potential energy |
| D. | conservation of kinetic energy |
| Answer» A. conservation of angular momentum | |
| Explanation: the consequence of newtons second law is the conservation of angular momentum. this, in accordance with newtons second law, provides the basic details to define parameters in the centrifugal pump. | |
| 100. |
in centrifugal pumps. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: centrifugal pumps are used to transport fluids. they transport fluids by conversion of energies. centrifugal pumps transport fluids by converting rotational kinetic energy to hydrodynamic energy. | |
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