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## Machine Design MCQ Set 1

1. If the controlling force line for a spring controlled governor when produced intersects the Y-axis at the origin, then the governor is said to be
a) stable
b) unstable
c) isochronous
d) none of the mentioned

Answer: c [Reason:] If the controlling force line for a spring controlled governor when produced intersects the Y-axis at the origin, then the governor is said to be isochronous. A spring controlled governor is said to be stable if the controlling force line when produced intersects the Y-axis below the origin. If the controlling force line for a spring controlled governor when produced intersects the Y-axis at the origin, then the governor is said to be unstable.

2. If the controlling force line for a spring controlled governor when produced intersects the Y-axis at the origin, then the governor is said to be unstable.
a) True
b) False

Answer: a [Reason:] A spring controlled governor is said to be stable if the controlling force line when produced intersects the Y-axis below the origin. If the controlling force line for a spring controlled governor when produced intersects the Y-axis at the origin, then the governor is said to be unstable.

3. The relation between the controlling force (Fc) and radius of rotation (r) for a stable spring controlled governor is
a) Fc = ar + b
b) Fc = ar – b
c) Fc = ar
d) Fc = a/r + b

Answer: b [Reason:] The relation between the controlling force (FC) and the radius of rotation (r) for the stability of spring controlled governors is given by the following equation FC = a.r – b

4. A spring controlled governor is said to be unstable, if the relation between the controlling force (Fc) and radius of rotation(r) is Fc = ar
a) True
b) False

Answer: b [Reason:] A governor is said to be unstable and the relation between the controlling force and the radius of rotation is, therefore FC = a.r + b

5. When the relation between the controlling force (Fc) and radius of rotation (r) for a spring controlled governor is Fc = ar + b, then the governor will be
a) stable
b) unstable
c) isochronous
d) none of the mentioned

Answer: b [Reason:] A governor is said to be unstable and the relation between the controlling force and the radius of rotation is, therefore FC = a.r + b

6. A Hartnell governor has its controlling force (Fc) given by Fc = ar + b, where r is the radius of rotation and a and b are constants. The governor becomes isochronous when
a) a is + ve and b = 0
b) a = 0 and b is +ve
c) a is +ve and b is -ve
d) a is +ve and b is also +ve

7. Calculate the vertical height of a Watt governor when it rotates at 60 r.p.m.
a) 0.248 m
b) 0.248 m
c) 0.448 m
d) 0.548 m

Answer: a [Reason:] Given : N1 = 60 r.p.m. ; N2 = 61 r.p.m. Initial height We know that initial height, h1 = 895/(N1)2 = 895/602 = 0.248 m

8. The power of a governor is the work done at
a) the governor balls for change of speed
b) the sleeve for zero change of speed
c) the sleeve for a given rate of change of change
d) each governor ball for given percentage change of speed

Answer: c [Reason:] Power of Governor: The work done by the governor on the sleeve to its equilibrium position for the fractional change in speed of governor is known as power of governor. It is actually a work done. Power = Main force × Sleeve movement.

9. In a governor, if the equilibrium speed is constant for all radii of rotation of balls, the governor is said to be
a) Stable
b) unstable
c) inertial
d) isochronous

Answer: d [Reason:] The governor is said to be Isochronous if the equilibrium speed is constant for all radii of rotation of balls.

10. A governor is said to be isochronous when the equilibrium speed is
a) variable for different radii of rotation of governor balls
b) constant for all radii of rotation of the balls within the working range
c) constant for particular radii of rotation of governor balls
d) constant for only one radius of rotation of governor balls

Answer: b [Reason:] Isochronism in governor means constant equilibrium speed for all the radii of rotation.

## Machine Design MCQ Set 2

1. In an open loop control system
a) Output is independent of control input
b) Output is dependent on control input
c) Only system parameters have effect on the control output
d) None of the mentioned

Answer: a [Reason:] When the input to a system is independent of the output from the system, then the system is called an open-loop or unmonitored system.

2. For open control system which of the following statements is incorrect ?
a) Less expensive
b) Recalibration is not required for maintaining the required quality of the output
c) Construction is simple and maintenance easy
d) Errors are caused by disturbances

Answer: b [Reason:] Most measuring instruments are open-loop control systems, as for the same input signal, the readings will depend upon things like ambient temperature and pressure.

3. A control system in which the control action is somehow dependent on the output is known as
a) Closed loop system
b) Semiclosed loop system
c) Open system
d) None of the mentioned

Answer: a [Reason:] When output of a system is measured and is continuously compared with the required value, then it is known as closed-loop or monitored system.

4. In closed loop control system, with positive value of feedback gain the overall gain of the system will
a) decrease
b) increase
c) be unaffected
d) none of the mentioned

Answer: a [Reason:] In closed loop control system, the output is measured and through a feedback transducer, it is sent to an error detector which detects any error in the output from the required value thus adjusting the input in a way to get the required output.

5. Which of the following is an open loop control system ?
a) Field controlled D.C. motor
b) Ward leonard control
d) Stroboscope

Answer: a [Reason:] In field control D.C. motor, the input is dependent of the output. So it is an open loop control system.

6. Which of the following statements is not necessarily correct for open control system ?
a) Input command is the sole factor responsible for providing the control action
b) Presence of non-linearities causes malfunctioning
c) Less expensive
d) Generally free from problems of non-linearities

Answer: b [Reason:] When the input to a system is independent of the output from the system, then the system is called an open-loop or unmonitored system. It is also called as a calibrated system. Most measuring instruments are open-loop control systems, as for the same input signal, the readings will depend upon things like ambient temperature and pressure.

7. In open loop system
a) the control action depends on the size of the system
b) the control action depends on system variables
c) the control action depends on the input signal
d) the control action is independent of the output

Answer: d [Reason:] When the input to a system is independent of the output from the system, then the system is called an open-loop or unmonitored system.

8. The following has tendency to oscillate.
a) Open loop system
b) Closed loop system
c) Both (a) and (b)
d) Neither (a) nor (b)

Answer: b [Reason:] Both open loop system and closed loop system have the tendency to oscillate.

9. A good control system has all the following features except
a) good stability
b) slow response
c) good accuracy
d) sufficient power handling capacity

Answer: b [Reason:] Repose is not included in a good control system.

10. A car is running at a constant speed of 50 km/h, which of the following is the feedback element for the driver ?
a) Clutch
b) Eyes
c) Needle of the speedometer
d) Steering wheel

Answer: c [Reason:] The needle of the speedometer is only the indicator of the speed and to keep the speed constant, the driver has to maintain the speed of 50 km/h.

## Machine Design MCQ Set 3

1. Sensitiveness of the governor is defined as the ratio of the
a) mean speed to the maximum equilibrium speed
b) mean speed to the minimum equilibrium speed
c) difference of the maximum and minimum equilibrium speeds to the mean speed
d) sum of the maximum and minimum equilibrium speeds to the mean speed

Answer: c [Reason:] The sensitiveness is defined as the ratio of the difference between the maximum and minimum equilibrium speeds to the mean equilibrium speed.

2. A governor is said to be stable, if the
a) radius of rotation of balls increases as the equilibrium speed decreases
b) radius of rotation of balls decreases as the equilibrium speed decreases
c) radius of rotation of balls increases as the equilibrium speed increases
d) radius of rotation of balls decreases as the equilibrium speed increases

Answer: c [Reason:] A governor is said to be stable when for every speed within the working range there is a definite configuration i.e. there is only one radius of rotation of the governor balls at which the governor is in equilibrium. For a stable governor, if the equilibrium speed increases, the radius of governor balls must also increase.

3. When the radius of rotation of balls ______________ as the equilibrium speed increases, the governor is said to be unstable.
a) remains constant
b) decreases
c) increases
d) none of the mentioned

Answer: b [Reason:] A governor is said to be unstable, if the radius of rotation decreases as the speed increases.

4. A governor is said to be isochronous when range of speed is zero for all radii of rotation of the balls within the working range, neglecting friction.
a) True
b) False

Answer: a [Reason:] A governor is said to be isochronous when the equilibrium speed is constant (i.e. range of speed is zero) for all radii of rotation of the balls within the working range, neglecting friction. The isochronism is the stage of infinite sensitivity.

5. A Porter governor can not be isochronous.
a) True
b) False

6. In a Hartnell governor, if a spring of greater stiffness is used, then the governor will be
a) less sensitive
b) more sensitive
c) unaffected of sensitivity
d) isochronous

Answer: a [Reason:] In general, the greater the lift of the sleeve corresponding to a given fractional change in speed, the greater is the sensitiveness of the governor.

7. When the speed of the engine fluctuates continuously above and below the mean speed, the governor is said to be
a) stable
b) unstable
c) isochronous
d) hunt

Answer: d [Reason:] The isochronous governor is not of practical use because the sleeve will move to one of its extreme positions immediately the speed deviates from the isochronous speed.

8. A very sensitive governor will cause hunting.
a) True
b) False

Answer: a [Reason:] A governor is said to be hunt if the speed of the engine fluctuates continuously above and below the mean speed. This is caused by a too sensitive governor which changes the fuel supply by a large amount when a small change in the speed of rotation takes place.

9. For isochronous Hartnell governor
a) mg + S1 / mg + S2 = r1/r2
b) mg – S1 / mg – S2 = r2/r1
c) S1/S2 = r1/r2
d) S2/S1 = r1/r2

10. Effort of a governor is the
a) mean force exerted at the sleeve for a given percentage change of speed
b) workdone at the sleeve for maximum equilibrium speed
c) mean force exerted at the sleeve for maximum equilibrium speed
d) none of the mentioned

Answer: a [Reason:] The effort of a governor is the mean force exerted at the sleeve for a given percentage change of speed (or lift of the sleeve).

## Machine Design MCQ Set 4

1. The degree of the Bezier curve with n control points is:
a) n + 1
b) n – I
c) n
d) 2n

Answer: a [Reason:] The degree of a Bézier curve defined by n+1 control points is n: In each basis function, the exponent of u is i + (n – i) = n. Therefore, the degree of the curve is n.

2. The degree of the B-spline with varying knot vectors:
a) Increases with knot vectors
b) Decreases with knot vectors
c) Remains constant
d) none of the mentioned

Answer: a [Reason:] Changing the degree of the curve due to the increase of knots will change the shape of the curve globally and will not be considered. Therefore, inserting a new knot causes a new control point to be added. In fact, some existing control points are removed and replaced with new ones by corner cutting.

3. C” continuity refers to:
a) Common tangent
b) Common point
c) Common curvature
d) Common normal

Answer: a [Reason:] C‘ continuity refers to Common curvature . C0 continuity refers to Common point. C” continuity refers to Common tangent.

4. C‘ continuity refers to:
a) Common tangent
b) Common point
c) Common curvature
d) Common normal

Answer: c [Reason:] C‘ continuity refers to Common curvature . C0 continuity refers to Common point. C” continuity refers to Common tangent.

5. C0 continuity refers to:
a) Common tangent
b) Common point
c) Common curvature
d) Common normal

Answer: b [Reason:] C‘ continuity refers to Common curvature . C0 continuity refers to Common point. C” continuity refers to Common tangent.

6. The number of non-coincidental points required to define the simplest surface are:
a) 4
b) 3
c) 2
d) 5

7. Convex hull property is satisfied by the following surface:
a) Bezier
b) B-spline
c) NURBS
d) All of the mentioned

Answer: b [Reason:] The curve that follows a convex hull property is B-spline.

8. The tensor product technique constraints surfaces by two curves.
b) Subtraction
c) Multiplying
d) Dividing

9. The degrees of freedom of a two-node bar element are:
a) 1
b) 2
c) 3
d) 4

10. The shape functions of a two-node bar element are:
a) Linear
c) Constant
d) None of the mentioned

## Machine Design MCQ Set 5

1. With reference to NC machines, which of the following statements is wrong
a) Both closed-loop and open-loop control systems are used
b) Paper tapes, floppy tapes and cassettes are used for data storage
c) Digitizers may be used as interactive input devices
d) Post processor is an item of hardware

2. In a point-to-point type of NC system
a) Control of position and velocity of the tool is essential
b) Control of only position of the tool is sufficient
c) Control of only velocity of the tool is sufficient
d) Neither position nor velocity need to be controlled

Answer: b [Reason:] Point to point is also sometimes called a positioning system. In PTP the objective of the machine tool control system is to move the cutting tool to predefined location. The speeder path by which this movement is accomplished is not important in point to point NC. Once the tool reaches the desired location, the machining operation is performed at that position.

3. GUI is the acronym for Graphical User Interface.
a) True
b) False

4. The heart of a computer is:
a) CPU
b) ALU
c) Monitor
d) Keyboard

Answer: a [Reason:] Keyboard is input device, monitor is output device.

5. The widely employed computer architecture for CAD/CAM applications is:
a) Mainframe-based system
b) Minicomputer-based system
c) Microcomputer-based system
d) Workstation-based system

Answer: d [Reason:] Workstation based system is widely used for CAD/cAM architecture.

6. Keyboard is a ___________ input device.
a) Graphical
b) Text
c) Numericals
d) All of the mentioned

7. Locating devices are classified as:
a) Text input devices
b) Graphics input devices
c) Both a and b
d) None of the mentioned

8. Mouse is a __________ type of input device.
a) Text
b) Graphics
c) Locating
d) All of the mentioned

Answer: c [Reason:] Through mouse we locate the required data or information.

9. Light pen is a:
a) Writing device
b) Drawing device
c) Locating device
d) Lighting device

Answer: b [Reason:] Light pen is used to draw on screen.

10. Digitizer is constructed on the basis of:
a) Magnetic tablet mechanism
b) Acoustic tablet mechanism
c) Optical tablet mechanism
d) both (a) and (b)