machine design MCQs – Page 3

Practise focused machine design questions with marked answers for exam preparation and subject revision.

machine design Mcqs
101. A hot short metal is_________________?
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A. ductile at high temperature

B. hard when hot

C. brittle when cold

D. brittle when hot

E. brittle under all conditions

102. A tube has the following advantage over pipe_________________?
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A. none of the above

B. greater shock absorption

C. smoother inside walls

D. all of the above

E. lighter and easier to handle

103. Aircraft body is usually fabricated by_________________?
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A. casting

B. precasting

C. rivetting

D. unconventional methods

E. welding

104. Residual stress in materials_________________?
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A. becomes zero when external load is removed

B. acts when external load is applied

C. is independent of external loads

D. is always harmful

E. is always beneficial

105. Basic shaft is one__________________?
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A. whose lower as well as upper deviations are zero

B. whose lower deviation is zero

C. does not exist

D. whose upper deviation is zero

E. none of the above

106. A tapered key which fits in a keyway in the hub and is flat on the shaft, is known as___________________?
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A. flat saddle key

B. gib head key

C. hollow saddle key

D. feather key

E. wood-ruff key

107. The ultimate strength of steel in tension in comparison to shear is in the ratio of__________________?
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A. 1:02

B. 1 : l

C. 2:03

D. 3 : 2

E. 2:01

108. A bench vice has following type of threads____________________?
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A. BSW

B. metric

C. square

D. buttress

E. acme
109. Maximum principal stress theory is applicable for_____________________?
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A. elastic materials

B. ductile materials

C. all of the above

D. brittle materials

E. none of the above

110. Set screws are_________________?
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A. none of the above

B. slotted for a screw driver and generally used with a nut

C. similar to small size tap bolts except that a greater variety of shapes of heads are available

D. used to prevent relative motion be-tween parts

E. similar to stud

111. If a material fails below its yield point, failure would be due to___________________?
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A. straining

B. sudden loading

C. creep

D. fatigue

E. impact loading

112. Split nut is a locking device in which_________________?
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A. a slot is cut partly in middle of nut and then slot reduced by tightening screw

B. a hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip

C. through slots are made at top and a cotter-pin is passed through these and a hole in the bolt, and cotter pin splitted and bent in reverse direction at the other end

D. one smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming

E. none of the above

113. For applications involving high stresses in one direction only the following type of thread would be best suited______________________?
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A. ISO metric thread

B. buttress thread

C. square thread

D. acme thread

E. British Association thread

114. In hydrodynamic bearings_____________________?
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A. do not require external supply of lubricant

B. grease is used for lubrication

C. none of the above

D. the oil film is maintained by supplying oil under pressure

E. the oil film pressure is generated only by the rotation of the journal
115. Allen bolts are___________________?
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A. self locking bolts

B. provided with hexagonal depression in head

C. designed for shock load

D. used in aircraft application

E. uniform strength bolts

116. The notch angle of the Izod impact test specimen is________________?
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A. 10

B. 20

C. 60.

D. 45

E. 30

117. The function of cutting oil when threading a pipe is to___________________?
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A. provide cooling action

B. help remove chips

C. all of the above

D. none of the above

E. lubricate the dies

118. The function of a washer is to___________________?
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A. provide bearing area

B. provide cushioning effect

C. absorb shocks and vibrations

D. provide smooth surface in place of rough surface

E. act as a locking device

119. The rated life of a bearing varies___________________?
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A. directly as load

B. inversely as cube of load

C. inversely as fourth power of load

D. none of the above

E. inversely as square of load

120. The piston rod of a steam engine is usually connected to the cross head by means of__________________?
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A. universal joint

B. cotter joint

C. bolted joint

D. universal coupling

E. kunckle joint

121. Spring index is___________________?
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A. load required to produce unit deflection

B. ratio of coil diameter to wire diameter

C. nothing

D. indication of quality of spring

E. its capability of storing energy

122. Which is correct statement ?
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A. a member made of steel will generally be more rigid than a member of equal load-carrying ability made of cast iron

B. a member made of cast iron will generally be. more rigid than a member of equal load carrying ability made of steel

C. both will be equally rigid

D. which one is rigid will depend on several other factors

E. none of the above

123. If a load W is applied instantaneously on a bar; then the stress induced in bar will___________________?
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A. increase with increase in y

B. depend on other considerations

C. none of the above

D. be independent of ratio of mass of load W to mass of bar (y)

E. decrease with decrease in y

124. In standard taper roller bearings, the angle of taper of outer raceway is___________________?
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A. 8

B. 5

C. 15

D. 40.

E. 25
125. In testing a material for endurance strength, it is subjected to_______________________?
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A. static as well as dynamic load

B. static load

C. completely reversed load

D. impact load

E. dynamic load

126. The maximum stress due to stress concentration in a bar having circular transverse hole, as compared to its static stress without hole will be_________________?
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A. same in both cases

B. 2 times more

C. 3 times more

D. 4 times more

E. unpredictable

127. The shear plane in case of bolts should_________________?
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A. be across threaded portion of shank

B. never be across the threaded portion

C. none of the above

D. be normal to threaded portion of shank

E. be parallel to axis of bolt

128. In composite or reverse laid ropes___________________?
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A. none of the above

B. wires in two adjacent strands are twisted in opposite direction

C. direction of twist of wires and strands are same

D. wires are not twisted

E. direction of twist of wires in strands is opposite to the direction of twist of strands

129. Guests theory of failure is applicable for following type of materials_________________?
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A. tough

B. elastic

C. ductile

D. plastic

E. brittle

130. When a bolt is subjected to shock loading, the resilience of the bolt should be considered in order to prevent breakage at_______________?
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A. in the middle

B. anywhere in the bolt

C. at the thread

D. shank

E. head

131. In order to obtain bolt of uniform strength____________________?
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A. increase its length

B. drill an axial hole through head up to threaded portion so that shank area is equal to root area of thread

C. all of the above

D. increase shank diameter

E. tighten die bolt properly

132. The designation M 33 x 2 of a bolt means___________________?
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A. metric threads of 33 mm outside diameter and 2 mm pitch

B. bolt of 33 mm nominal diameter having 2 threads per cm

C. metric threads with cross-section of 33 mm

D. metric threads of 33 nos in 2 cm.

E. none of the above

133. Which of the following is a permanent fastening ?
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A. screws

B. cotters

C. keys

D. rivets

E. bolts

134. If the tearing efficiency of a riveted joint is 75%, then the ratio of diameter of rivet to the pitch is equal to___________________?
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A. 0.75

B. 0.25

C. 0.5

D. 0.2

E. 0.6

135. Rivets are generally specified by_______________?
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A. all of the above

B. thickness of plates to be riveted

C. length of rivet

D. nominal diameter

E. diameter of head

136. Jam nut is a locking device in which _____________________?
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A. one smaller nut is tightened over main nut and main nut tightened against smaller one by loosening, creating friction jamming

B. a slot is cut partly in middle of nut and then slot reduced by tightening a screw

C. through slots are made at top and a cotter-pin is passed through these and a hole in the bolt, and cotter spitted and bent in reverse direction at other end

D. a hard fiber or nylon cotter is recessed in the nut and becomes threaded as the nut is screwed on the bolt causing a tight grip

E. none of the above

137. A key capable of tilting in a recess milled out in a shaft is known as______________________?
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A. feather key

B. wood-ruff key

C. hollow saddle key

D. flat saddle key

E. gib head key

138. Buttress threads are usually found on____________________?
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A. screw jack

B. feed mechanisms

C. spindles of bench vices

D. screw cutting lathes

E. railway carriage couplings