Mechanical Operations Multiple Choice Questions on “Magnetic Separation”.
1. What does the below equation represents?
a) Filtration area
b) Velocity of filtration
c) Speed of filtration
d) Flow of filtrate
Answer: a
Clarification: The rate of filtration is represented by the above equation, where V is the volume of filtrate which has passed in time t and A is the area.
2. For any filtration pressure, the rate of flow is ______ at the beginning.
a) Constant
b) Greatest
c) Smallest
d) Critical
Answer: b
Clarification: For any filtration pressure, the rate of flow is greatest at the beginning of the process and this is because the resistance is minimum.
3. ____ may cause plugging of pores.
a) High final rates
b) Low initial rates
c) High initial rates
d) Low final rates
Answer: c
Clarification: High initial rates of filtration may result in the initial layers can be appreciably influence the structure of the whole filter cake.
4. Increase of pressure drop forms ______
a) Vast volume
b) Deeper cake
c) Lighter cake
d) Denser cake
Answer: d
Clarification: With a compressible cake, increase of pressure difference or the rate of formation can form a denser cake.
5. What does the following equation gives?
(1-e)A lρs
a) Mass of solid in filter
b) Mass of cake
c) Mass of filter
d) Mass of fluid
Answer: a
Clarification: The variable l and V are connected, and the relation between then is given by the above equation, where ps is the density of solids.
6. Calculate the mass, if density of solid 1.20, e is 0.2 and has an area of 45 m2 and length 10 m?
a) 450 kg
b) 45 kg
c) 360 kg
d) 100 kg
Answer: c
Clarification: As (1 – 0.2)*45*10 = 360 kg.
7. What does the following equation gives?
(e) Alρs
a) Mass of solid in filter
b) Mass of liquid in filter
c) Mass of filter
d) Mass of fluid
Answer: b
Clarification: This equation is used in basic filtration equation and used to find the mass of liquid in filter and where A is area and l is the length.
8. Calculate the liquid in filter, if e is 2.0 and Area and length are 120 m2 and 2 m and consider water as fluid?
a) 250 kg
b) 240 kg
c) 480 kg
d) 260 kg
Answer: c
Clarification: As we know that the mass is given as 2.0*120*2 = 480 kg.
9. Particles will be compacted, if initial pressure is ____
a) High
b) Low
c) Constant
d) Open to atmosphere
Answer: a
Clarification: If the initial pressure is high, the first particles are caught and will be compacted into a tight mass that largely fills the pores.
10. The initial pressure of will form precipitate, if initial pressure is _____
a) High
b) Low
c) Constant
d) Open to atmosphere
Answer: b
Clarification: If initial pressure is low, the initial layer of precipitate will be more open so that rates of filtration will be higher.