416. The process by which shell like casting (like toys) are made is

1. 1. Shell moulding

   
   
   

   2. Centrifugal casting

   
   
   

   3. Slush casting

   
   
   

   4. Die casting

   
   
   

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1. View Hint View Answer Discuss in Forum

   Hollow sections made by this

   Correct Option: D

   Hollow sections made by this

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417. Negative allowance is provided on the pattern to take care of

1. 1. The distortion allowance

   
   
   

   2. The draft allowance

   
   
   

   3. The machining allowance

   
   
   

   4. The shake allowance

   
   
   

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1. View Hint View Answer Discuss in Forum

   Allowance for ramming

   Correct Option: D

   Allowance for ramming

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418. A sprue in a sand mould has a top diameter of 20 mm and height of 200 mm. The velocity of the molten metal at the entry of the sprue is 0.5 m/s. Assume acceleration due to gravity as 9.8 m/s² and neglect all losses, If the mould well ventilated, the velocity (upto 3 decimal points accuracy) of the molten metal at the bottom of the sprue is ______ m/s.

1. 1. 2.034

   
   
   

   2. 3.043

   
   
   

   3. 2.043

   
   
   

   4. 2.045

   
   
   

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1. View Hint View Answer Discuss in Forum

   
   We know that,
   V₂ = √2gh₂ = √2 × 9.81 × h₂ = 0.5
   h₂ = 0.01274 m
   h₃ = h₂ + 0.2 = 0.2127 m
   V₃ = √2gh₃ = 2.043 m/sec

   Correct Option: C

   
   We know that,
   V₂ = √2gh₂ = √2 × 9.81 × h₂ = 0.5
   h₂ = 0.01274 m
   h₃ = h₂ + 0.2 = 0.2127 m
   V₃ = √2gh₃ = 2.043 m/sec

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419. Gray cast iron blocks of size 100 mm × 50 mm × 10 mm with a central spherical cavity of diameter 4 mm are sand cast. The shrinkage allowance for the pattern is 3%. The ratio of the volume of the pattern to volume of the casting is

1. 1. 0.913

   
   
   

   2. 1

   
   
   

   3. 0.951

   
   
   

   4. 0.915

   
   
   

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1. View Hint View Answer Discuss in Forum

   Ratio of volume of pattern to casting
   

   	[(0.97 × 100)(0.97 × 50)(0.97 × 10)]	= 0.913
   	(100 × 50 × 10

   
   Volume of cavity is assumed to be small and negligible.

   Correct Option: A

   Ratio of volume of pattern to casting
   

   	[(0.97 × 100)(0.97 × 50)(0.97 × 10)]	= 0.913
   	(100 × 50 × 10

   
   Volume of cavity is assumed to be small and negligible.

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420. In full mould (cavity-less) casting process, the pattern is made of

1. 1. expandable polystyrene

   
   
   

   2. wax

   
   
   

   3. epoxy

   
   
   

   4. plaster of Paris

   
   
   

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1. View Hint View Answer Discuss in Forum

   The pattern is made of expanded polystyrene.

   Correct Option: C

   The pattern is made of expanded polystyrene.

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