Related Questions

Lessing ring is formed by the addition of a partition across the centre of a raschig ring, which results in an area increase of about __________ percent.
A 5
B 20
C 35
D 55
Sphericity of raschig ring (whose length and diameter are equal) is
A >1
B 1
C 2
How many liters of a 90% of concentrated acid needs to be mixed with a 75% Solution of concentrated acid to get a 30 liter Solution of 78% concentrated acid?
A 8
B 6
C 7
D 9
Maximum size of the raschig rings used in a packed tower is about __________ of the coloumn diameter.
A $${\frac{1}{{10}}^{{\text{th}}}}$$
B $${\frac{1}{{20}}^{{\text{th}}}}$$
C $${\frac{1}{{30}}^{{\text{th}}}}$$
D $${\frac{1}{{50}}^{{\text{th}}}}$$
Diameter of raschig rings used in packed tower in industry is normally around __________ inches.
A 2
B 8
C 12
D 18
Use of raschig rings in place of crushed stones as packing in packed beds (other things being same)
A Increases pressure drop, increases surface area
B Increases pressure drop, decreases surface area
C Decreases pressure drop, increases surface area
D Decreases pressure drop, decreases surface area
For raschig rings, the sphericity is
A 0.5
B 1
C $$\sqrt 3 $$
Six bells starts ringing logether and ring at intervals of 4, 8, 10, 12, 15 and 20 seconds respectively. How many times will they ring together in 60 minutes?
A 15
B 16
C 30
D 31
The function of a first compression ring (top ring) is that it
A Increases the combustion temperature
B Creates swirl
C Maintains a seal and prevents the fuel leakage
D Maintains a seal and prevents escape of burned gases and loss of pressure in the combustion chamber
M.I. of a thin ring (external diameter D, internal diameter d) about an axis perpendicular to the plane of the ring, is
A $$\frac{\pi }{{64}}\left( {{{\text{D}}^4} + {{\text{d}}^4}} \right)$$
B $$\frac{\pi }{{32}}\left( {{{\text{D}}^4} - {{\text{d}}^4}} \right)$$
C $$\frac{\pi }{{32}}\left( {{{\text{D}}^4} + {{\text{d}}^4}} \right)$$
D $$\frac{\pi }{{32}}\left( {{{\text{D}}^4} \times {{\text{d}}^4}} \right)$$

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