Mechanical Operations - Study Mode
[#391] In case of a hammer crusher, the final product size depends on the
Correct Answer
(D) All of the above
[#392] Energy consumed for crushing one ton of material ranges from __________ kWh.
Correct Answer
(B) 0.5 to 1.5
[#393] A 30% (by volume) suspension of spherical sand particles in a viscous oil has a hindered settling velocity of 4.44 μm/s. If the Richardson Zaki hindered settling index is 4.5, then the terminal velocity of a sand grain is
Correct Answer
(B) 1 μm/s
Explanation
Solution: The Richardson-Zaki equation relates the hindered settling velocity (V h ) to the terminal settling velocity (V t ) through the expression: V h = V t × (1 - φ) n where φ is the volume fraction of solids (here, φ = 0.30) and n is the Richardson-Zaki index (given as 4.5). First calculate (1 - φ): 1 - 0.30 = 0.70 Then raise it to the power of n: (0.70) 4.5 ≈ 0.2008 Rearranging the equation for terminal velocity gives: V t = V h / (1 - φ) n Substituting the values: V t = 4.44 μm/s / 0.2008 ≈ 22.1 μm/s Therefore, the terminal velocity of a sand grain is 22.1 μm/s.
[#394] Supporting legs of a plate and frame filter is normally made of
Correct Answer
(B) Cast iron
[#395] In classification, particles are said to be equal settling, if they have the same terminal velocities in the
Correct Answer
(D) Both B and C