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# Multiple choice question for engineering

## Set 1

1. The pair is known as a higher pair, when the relative motion between the elements of a pair is
a) turning only
b) sliding only
c) rolling only
d) partly turning and partly sliding

Answer: d [Reason:] When the two elements of a pair have a line or point contact when relative motion takes place and the motion between the two elements is partly turning and partly sliding, then the pair is known as higher pair.

2. Which of the following is a higher pair?
a) Belt and pulley
b) Turning pair
c) Screw pair
d) Sliding pair

Answer: a [Reason:] Belt and pulley are higher pairs as the motion is partly turning and partly sliding between them.

3. When the connection between the two elements is such that only required kind of relative motion occurs, it is known as self-closed pair.
a) True
b) False

Answer: a [Reason:] When the two elements of a pair are connected together mechanically in such a way that only required kind of relative motion occurs, it is then known as self closed pair.

4. When the elements of a pair are kept in contact by the action of external forces, the pair is said to be a
a) lower pair
b) higher pair
c) self-closed pair
d) force-closed pair

Answer: d [Reason:] When the two elements of pair are not connected mechanically but are kept in contact by the action of external forces, the pair is said to be a forced-closed pair.

5. A pair of friction discs is an example of rolling pair.
a) True
b) False

Answer: b [Reason:] A pair of discs are higher pairs as the motion is partly turning and partly sliding between them.

6. The lower pairs are ___________ pairs.
a) self-closed pair
b) force-closed pair
c) screw pair
d) none of the mentioned

Answer: a [Reason:] When the two elements of a pair are connected together mechanically in such a way that only required kind of relative motion occurs, it is then known as self closed pair. The lower pairs are self closed pairs.

7. The cam and follower is an example of
a) sliding pair
b) rolling pair
c) lower pair
d) higher pair

Answer: d [Reason:] The cam and follower is an example of higher pair as it is kept in contact by the forces exerted by spring and gravity.

8. Which of the following is an example of higher pair?
a) Toothed gearing
b) Belt and rope drive
c) Ball and roller bearing
d) All of the mentioned

9. An automobile steering gear is an example of
a) sliding pair
b) rolling pair
c) lower pair
d) higher pair

10. A pair is said to be kinematic pair, if the relative motion between them is completely or successfully constrained.
a) True
b) False

Answer: a [Reason:] The two links or elements of a machine, when in contact with each other, are said to form a pair. If the relative motion between them is completely or successfully constrained, the pair is known as kinematic pair.

## Set 2

1. Coordination number of simple cubic unit cell is equal to
a) 4
b) 6
c) 8
d) 2

Answer: b [Reason:] Six atoms are nearest to simple cubic cell. Coordination number is the number of atom adjacent to one atom.

2. Coordination number of face centered cubic unit cell is equal to
a) 4
b) 6
c) 8
d) 12

Answer: d [Reason:] Twelve atoms are nearest to face centered cubic cell. Coordination number is the number of atom adjacent to one atom.

3. Coordination number of body centered cubic unit cell is equal to
a) 4
b) 6
c) 8
d) 2

Answer: d [Reason:] Two atoms are nearest to body centered cubic cell. Coordination number is the number of atom adjacent to one atom.

4. Effective number of atom in simple cubic unit cell is equal to
a) 4
b) 1
c) 8
d) 2

Answer: b [Reason:] 8× 8⁄8=1 and total number of atoms at corners= 8. Each corner atom is shared by total 8 unit cells.

5. Effective number of atom in face centered unit cell is equal to
a) 4
b) 1
c) 8
d) 2

Answer: b [Reason:] 8× 1⁄8+6×1⁄2=1 and total number of atoms at corners= 8, total atoms at faces= 6.Each corner atom is shared by total 8 unit cells.

6. Effective number of atom in body centered cubic unit cell is equal to
a) 4
b) 1
c) 8
d) 2

Answer: d [Reason:] 8× 8⁄8+1=1 and total number of atoms at corners= 8, number of atoms at body centre=1.Each corner atom is shared by total 8 unit cells.

7. Atomic Packing fraction in percentage of simple cubic structure is given by
a) 74
b) 52
c) 68
d) 66

Answer: b [Reason:] a=r and APF= (volume of effective number of atoms/volume of unit cell).

8. Atomic Packing fraction in percentage of body centered structure is equal to
a) 74
b) 52
c) 68
d) 66

Answer: c [Reason:] r=(√3)/4×a and APF= (volume of effective number of atoms/volume of unit cell).

9. If radius of copper is 1.27 Aͦ, then density of copper in Kg⁄m^3 will be
a) 100.01
b) 86.25
c) 8979
d) 7968

Answer: c [Reason:] Copper have Face centered cubic structure and atomic weight 63.5.

10. Atomic Packing fraction in percentage of face centered cubic structure is equal to
a) 74
b) 52
c) 68
d) 66

Answer: a [Reason:] a=2√2×r and APF= (volume of effective number of atoms/volume of unit cell).

## Set 3

1. Chip flow velocity during machining process is 0.2m/s with chip thickness ratio of 0.6. What is the value of cutting velocity?
a) 0.33m/s
b) 0.43m/s
c) 0.23m/s
d) 0.13m/s

Answer: a [Reason:] Chip flow velocity= chip thickness ratio * cutting velocity. Hence cutting velocity = 0.33m/s.

2. Chip flow velocity during machining process is 1.2m/s with chip thickness ratio of 0.6. What is the value of cutting velocity?
a) 1.33m/s
b) 4m/s
c) 3m/s
d) 2m/s

Answer: d [Reason:] Chip flow velocity= chip thickness ratio * cutting velocity. Hence cutting velocity = 2m/s.

3. Shear velocity during machining process is 0.2m/s with chip thickness ratio of 0.6. Shear angle is 30 degree and rake angle is 15 degree. What is the value of cutting velocity?
a) 0.33m/s
b) 0.43m/s
c) 0.20m/s
d) 0.13m/s

Answer: c [Reason:] Chip flow velocity= chip thickness ratio * cutting velocity and chip flow velocity= shear velocity*sin (Shear angle)/(cos(rake angle)).

4. Shear velocity during machining process is 1.2m/s with chip thickness ratio of 0.6. Shear angle is 30 degree and rake angle is 15 degree. What is the value of cutting velocity?
a) 0.33m/s
b) 0.43m/s
c) 1.20m/s
d) 0.13m/s

Answer: c [Reason:] Chip flow velocity= chip thickness ratio * cutting velocity and chip flow velocity= shear velocity*sin (Shear angle)/(cos(rake angle)).

5. Feed force of 210Kg and cutting force of 310Kg are applied using a tool of rake angle 10 degrees. If chip thickness ratio is 0.36, what will be the value of shear angle in degrees?
a) 20.17
b) 44.13
c) 30.606
d) 21.571

Answer: a [Reason:] tan (shear angle)= (r*cos(rake angle))/ (1-r*sin(rake angle)). Where r is the chip thickness ratio.

6. Feed force of 210Kg and cutting force of 310Kg are applied using a tool of rake angle 10 degrees. If chip thickness ratio is 0.36, what will be the value of shear force in Kg?
a) 20.17
b) 44.13
c) 30.606
d) 215.71

Answer: d [Reason:] tan (shear angle)= (r*cos(rake angle))/ (1-r*sin(rake angle)). Shear force=Cutting force*cos(shear angle)-feed force*sin (shear angle).

7. Feed force of 210Kg and cutting force of 310Kg are applied using a tool of rake angle 10 degrees. If chip thickness ratio is 0.36, what will be the value of normal force in Kg?
a) 20.17
b) 44.13
c) 306.06
d) 215.71

Answer: a [Reason:] tan (shear angle)= (r*cos(rake angle))/ (1-r*sin(rake angle)). Normal force=-Cutting force*sin (shear angle)+feed force*cos(shear angle).

8. Feed force of 210Kg and cutting force of 310Kg are applied using a tool of rake angle 10 degrees. If chip thickness ratio is 0.36, what will be the value of coefficient of friction?
a) .20
b) .44
c) .97
d) .21

Answer: c [Reason:] tan (shear angle)= (r*cos(rake angle))/ (1-r*sin(rake angle)). Use merchant circle diagram to find coefficient of friction.

9. Feed force of 210Kg and cutting force of 310Kg are applied using a tool of rake angle 10 degrees. If chip thickness ratio is 0.36, what will be the value of friction angle?
a) 20.17
b) 44.13
c) 30.606
d) 21.571

Answer: b [Reason:] tan (shear angle)= (r*cos(rake angle))/ (1-r*sin(rake angle)). Use merchant circle diagram to find coefficient of friction and then use, Coefficient of friction= tan (friction angle).

10. Which of the following will have maximum amount of chips during machining?
a) Ductile material
b) Brittle material
c) Cast iron
d) None of the mentioned

Answer: a [Reason:] Ductile material produces more chip than brittle material.

## Set 4

1. Positive rake angle is given for machining of:
a) Brittle material
b) Ductile material
c) Both hard and soft material
d) None of the mentioned

Answer: b [Reason:] Positive rake angle have better chip flow. As amount of chip flow in ductile material is large, hence positive back rake angle tool will be a better option for machining ductile material.

2. Negative back rake angle is given for machining of:
a) Brittle and hard material
b) Soft material
c) Ductile material
d) Soft and ductile material

Answer: a [Reason:] Brittle material has smaller amount of chip flow and are very strong. As negative back angle tool are very strong, hence these are used for machining of brittle and hard material.

3. Which of the following will give maximum chip flow during machining?
a) Hard material
b) Ductile material
c) Brittle material
d) All of the mentioned

Answer: b [Reason:] Brittle material breaks very easily due to which they have maximum chip flow.

4. With increase in rake angle of tool, tool life will
a) Increase
b) Decrease
c) Remains constant
d) First increase then decrease

Answer: d [Reason:] With increase in rake angle chip flow rate increases and hence the heat generated is carried away with chips at faster rate due to which tool life increases. For large back rake angle, tool become very thin and its life decrease.

5. What is the optimum value of positive rake angle in degrees for maximum tool life?
a) 10
b) 12
c) 15
d) 20

Answer: c [Reason:] At 15 degree chip removal rate and strength of tool are optimum and hence tool life will be maximum.

6. For machining of carbide material which of the following tool will be preferred?
a) Large positive rake angle tools
b) Large negative rake angle tools
c) Zero rake angle tools
d) Small point angle tools

Answer: b [Reason:] Carbide materials are very hard hence strong tool is required for their machining. Tools with large negative back rake angle are stronger.

7. Which of the following tool will give best result for machining of brass?
a) Large positive rake angle tools
b) Large negative rake angle tools
c) Zero rake angle tools
d) Small point angle tools

Answer: c [Reason:] Brass is neither very hard nor very soft and zero rake angle tool would be best option for machining of brass.

8. With increase in side cutting edge angle keeping width of cut constant, depth of cut will
a) Increase
b) Decrease
c) First increase then decrease
d) Remains constant

Answer: b [Reason:] Depth of cut is directly proportional to cos of side cutting edge angle, hence it decreases with increase in side cutting edge angle.

9. With increase in rake angle of tool, tool life will
a) Increase
b) Decrease
c) Remains constant
d) First increase then decrease

Answer: d [Reason:] With increase in side cutting edge angle width of cut decreases, hence the chip removal rate is good due to which toll life increases. After some limit increasing side cutting angle will decrease tool life to increase in interaction of tool with work piece.

10. What is the optimum value of side cutting edge in degrees for maximum tool life?
a) 20
b) 22
c) 25
d) 30

Answer: d [Reason:] At 30 degree chip removal rate and strength of tool are optimum and hence tool life will be maximum.

## Set 5

1. Which of the following is correct reason for keeping transverse force minimum in turning of slender rod?
a) To enhances surface finish
b) To increase productivity
c) To increase efficiency of cutting
d) To reduce undesired vibration during turning

Answer: d [Reason:] Vibration is the major problem during turning of slandered rod due to which it is advised to keep transverse force minimum during turning of slender rod.

2. Self centered chuck has ___ number of jaws.
a) 10
b) 1
c) 2
d) 3

Answer: 3 [Reason:] 3-jaw chucks are also known as self centered chuck, hence they have 3 jaws.

3. During groove cutting in a lathe, by using a parting tool, which of the following forces are encountered?
a) Tangential
c) Tangential, Radial and Axial
d) Tangential and Radial

Answer: c [Reason:] Radial, axial and tangential forces are encountered during groove cutting on a lathe machine.

4. Which of the following will give best result for taper turning on internal surface?
a) Using tailstock offset method
b) Using taper attachment method
c) Using form tool
d) Using compound rest method

Answer: d [Reason:] Compound rest method is generally used for taper turning on internal surfaces.

5.Lead screw of lathe have double start thread with a pitch of 4mm. What should be the ratio of speed between lead screw and spindle for producing a single start thread of 2 mm pitch?
a) 1:2
b) 1:3
c) 1:4
d) 1:5

Answer: c [Reason:] Number of starts and pitch of lathe is directly proportional to speed of spindle required.

6. Let screw of 2mm pitch is needed to be cut on lathe machine. Lead screw of lathe has pitch of 6mm. Which of the following statement is correct?
a) Speed of lead screw>speed of spindle
b) Speed of lead screw<speed of spindle
c) Speed of lead screw=speed of spindle
d) None of the mentioned

Answer: b [Reason:] Speed of lead screw decreases in relative to speed of spindle as many times the required pitch is larger than pitch of lead screw.

7. Speed of lead screw decreases in relative to speed of spindle as many times the required pitch is larger than pitch of lead screw.
a) True
b) False

Answer: a [Reason:] Lead screw will move axially equal to pitch of lead screw after one complete rotation of lead screw.

8. Speed of lead screw decreases in relative to speed of spindle as many times the required pitch is smaller than pitch of lead screw.
a) True
b) False

Answer: b [Reason:] Lead screw will move axially equal to pitch of lead screw after one complete rotation of lead screw.

9. What are thread chasers?
a) Multipoint cutting tool
b) Single point cutting tool
c) A work holding device
d) None of the mentioned