1. Collectors forms ____
Answer: a [Reason:] Collectors are the material which form surface films on the particles, these films are thicker that produced by promoters.
2. Which of the following is a collector?
a) Sodium ethyl Xanthate
b) Pine oil
c) Timber oil
d) Cocoa oil
Answer: b [Reason:] Pine oil is a most commonly used collector, petroleum compounds are generally used though they are greasy forth maker.
3. Surfaces in either cases are manipulated using ____
Answer: b [Reason:] Surface manipulation can be done using the substances called as modifiers which either absorbed on the surface of particle or react chemically.
4. Which of the following is the right order?
a) Forth > Modifier > Collector
b) Forth < Modifier < Collector
c) Forth > Collector > Modifier
d) Forth < Collector < Modifier
Answer: d [Reason:] Initially forth is formed using a suitable forthing agent and then collectors can be applied to increase the film thickness and if needed modifiers are used.
5. Which of the following can mostly affect the flotation process?
d) Rate of reaction
Answer: c [Reason:] The pH which is a regulating or critical factor can affect the flotation process and can be adjusted by lime, caustic soda and soda ash.
6. What does the below equation represent?
a) Francis factor
b) Newton factor
c) Belly factor
d) Nauman factor
Answer: a [Reason:] For laminar settling of a spherical particle in a cylindrical vessel, Francis has proposed a correction factor, Where De is diameter of container.
7. When carried correct calculation the following equation results in ___
ρs (1-ε)+ρf ε
a) Final density
b) Bulk density
c) Bulk Volume
d) Final Volume
Answer: b [Reason:] The bulk density ρ_b can be calculated by the above equation, where ε is the volume of fraction void liquid in a suspension.
8. When the particle have the same terminal velocity, they are said to be ___
a) Kinematical falling
b) Partially falling
c) Equally falling
d) Free falling
Answer: b [Reason:] The basic criterion of separation of particles A and B are the difference in the terminal velocity, but when it is equal they are said to be equally falling.
9. The ratio of sizes of equally falling particles is called ___
a) Reflux ratio
b) Reduction ratio
c) Settling ratio
d) Steeling ratio
Answer: c [Reason:] The ratio of sizes of particles say A and B when they are equally falling is called as the settling ratio i.e. DA/DB.
10. What is the laboratory test defined for heavy medium separation?
a) Float and sink test
b) Weight test
c) Bubble test
d) Forth test
Answer: a [Reason:] In commercial practices, a sample feed is first tested in the laboratory using what is called the float and sink test experiment.