Machine Design

101. The endurance limit of a material with finished surface in comparison to rough surface is

1. more
2. less
3. same
4. more or less depending on quantum of load
5. unpredictable.

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102. The fatigue life of a part can be improved by

1. electroplating
2. polishing
3. coating
4. shot peening
5. heat treating.

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103. The fatigue limit of a material

1. is greatly decreased by poor surface conditions
2. remains same irrespective of surface conditions
3. depends mainly on core composition
4. is dependent upon yield strength of material
5. none of the above.

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104. The following type of nut is used with alien bolt

1. alien nut
2. hexagonal nut
3. slotted nut
4. castle nut
5. any one of the above.

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105. The function of a washer is to

1. provide cushioning effect
2. provide bearing area
3. absorb shocks and vibrations
4. provide smooth surface in place of rough surface
5. act as a locking device.

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106. The function of cutting oil when threading a pipe is to

1. provide cooling action
2. lubricate the dies
3. help remove chips
4. all of the above
5. none of the above.

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107. The included angle in unified of American National threads is

1. 60°
2. 55°
3. 47°
4. 29°
5. none of the above.

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108. The maximum stress due to stress concentration in a bar having circular transverse hole, as compared to its static stress without hole will be

1. same in both cases
2. 2 times more
3. 3 times more
4. 4 times more
5. unpredictable.

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109. The notch angle of the Izod impact test specimen is

1. 10°
2. 20°
3. 30°
4. 45°
5. 60°.

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110. The permissible stress for carbon steel under static loading is generally taken as

1. 2000-3000 kg/pm2
2. 3000-4000 kg/cm2
3. 4000-4500 kg/cm2
4. 7500-10,000 kg/cm2
5. 10,000-15,000 kg/cm2.

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