Q3.The ratios of the laminar hydrodynamic boundary layer thickness to thermal
boundary layer thickness of flows of two fluids P and Q on a flat plate are 1/2
and
2 respectively. The Reynolds number based on the plate length for both the flows
is 104. The Prandtl and Nusselt numbers for P are 1/8
and 35 respectively. The
Prandtl and Nusselt numbers for Q are respectively
Q4.A cubic casting of 50mm side undergoes volumetric solidification shrinkage and
volumetric solid contraction of 4% and 6% respectively. No. riser is used.
Assume uniform cooling in all directions. The side of the cube after solidification
and contraction is
Answer : Option AExplaination / Solution:
Volumetric solidification shrinkage and volumetric solid contraction cause
decrease in dimensions.
Q8.The variable cost (V) of manufacturing a product varies according to the equation
V= 4q, where q is the quantity produced. The fixed cost (F) of production of same
product reduces with q according to the equation F = 100/q. How many units
should be produced to minimize the total cost (V+F)?
Answer : Option AExplaination / Solution:
Checking with all options in formula: (4q+100/q) i.e. (V+F). Option A gives the
minimum cost.
Q10.Match the following criteria of material failure, under biaxial stresses σ1 and σ2 and yield stress σy , with their corresponding graphic representations :
P. Maximum-normal-stress criterion L.
Q. Maximum-distortion-energy criterion M.
R. Maximum-shear–stress criterion N.
Answer : Option CExplaination / Solution: No Explaination.
Total Question/Mark :
Scored Mark :
Mark for Correct Answer : 1
Mark for Wrong Answer : -0.5
Mark for Left Answer : 0