91. The atomic packing factor for a material with body centered cubic structure is _______ .

1. 1. APF = 0.68

   
   
   

   2. APF = 1.68

   
   
   

   3. APF = 0.78

   
   
   

   4. APF = - 1.68

   
   
   

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1. View Hint View Answer Discuss in Forum

   4r = a√3
   
   

   a =	4r
   	√3

   
   APF = 0.68

   Correct Option: A

   4r = a√3
   
   

   a =	4r
   	√3

   
   APF = 0.68

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92. The crystal structure of austenite is

1. 1. body centered cubic

   
   
   

   2. face centered cubic

   
   
   

   3. hexagonal closed packed

   
   
   

   4. body centered tetragonal

   
   
   

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1. View Hint View Answer Discuss in Forum

   γ - Austenite has FCC Structure.

   Correct Option: C

   γ - Austenite has FCC Structure.

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93. Match the following Process
    

    Process	Defect
    A. Casting	1. Lack of penetration
    B. Welding	2. Penetration
    C. Extrusion	3. Flange wrinkles
    D. Deepdrawing	4. Centre burst

1. 1. A– 3, B–2, C–4, D–1

   
   
   

   2. A– 1, B–2, C–4, D–3

   
   
   

   3. A– 1, B–3, C–4, D–2

   
   
   

   4. A– 1, B–3, C–4, D–2

   
   
   

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1. View Hint View Answer Discuss in Forum

   A– 1, B–2, C–4, D–3

   Correct Option: B

   A– 1, B–2, C–4, D–3

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94. Machining process job
    List-I
    A. LBM
    B. EDM
    C. Chemical milling
    D. USM
    List-II
    1. Making a printed circuit board
    2. Drilling a hole in glass plate
    3. Making a die out of a die steel block
    4. Cutting a polyester sheet

1. 1. A – 2, B – 3, C – 1, D – 4

   
   
   

   2. A – 4, B – 2, C – 1, D – 3

   
   
   

   3. A – 4, B – 2, C – 1, D – 3

   
   
   

   4. A – 4, B – 3, C – 1, D – 2

   
   
   

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1. View Hint View Answer Discuss in Forum

   A – 4, B – 3, C – 1, D – 2
   LBM – cutting a polyester sheet
   EDM – Making a die out of a die steel block.
   Chemical milling – Making a printed circuit board.
   USM – Drilling a hole in glass plate

   Correct Option: D

   A – 4, B – 3, C – 1, D – 2
   LBM – cutting a polyester sheet
   EDM – Making a die out of a die steel block.
   Chemical milling – Making a printed circuit board.
   USM – Drilling a hole in glass plate

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95. Match the processes with their characteristics.
    

    Processes	Characteristics
    P. Electrical	1. No residual Discharge Machining stress
    Q. Ultrasonic machining	2. Machining of electrically conductive materials
    R. Chemical machining	3. Machining of glass
    S. Ion Beam Machining	4. Nanomachining

1. 1. P-2, Q-3, R-1, S-4

   
   
   

   2. P-3, Q-2, R-1, S-4

   
   
   

   3. P-3, Q-2, R-4, S-1

   
   
   

   4. P-2, Q-4, R-3, S-1

   
   
   

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1. View Hint View Answer Discuss in Forum

   P-2, Q-3, R-1, S-4

   Correct Option: A

   P-2, Q-3, R-1, S-4

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