1. Which of the following is best for charging the particles?
Answer: b [Reason:] Ion bombardment is the strongest and perhaps the most efficient mechanism for charging solid particles.
2. If a dielectric and conductor are placed in path of mobile ions, then it will generate _____
a) Semi charge
Answer: c [Reason:] A dielectric and conductor are when placed in path of mobile ions, a portion of the surface of each particle will be given a strong electrical charge.
3. If a particle is placed in a grounded surface, then _____
a) Mobiles ions are stopped
b) Charges get renewed
c) Flow of ions gets retarded
d) End of dielectric
Answer: a [Reason:] If a group of particles is placed on a grounded surface in the path of these mobile ions, it will be found that mobile ions are stopped.
4. What does the below diagram represent?
a) Cyclone separator
b) Plate type separator
c) Craved separator
d) Twice separator
Answer: b [Reason:] The plate type merely consists of two plates that are vertical suspended relatively close to each other grounded one or more positively or negatively charged.
5. What is the capacity of a rotor type separator?
a) 1500 lb/hr
b) 2000 lb/hr
c) 3000 lb/hr
d) 500 lb/hr
Answer: b [Reason:] One rotor gives sufficient type of capacity but the material need more than one pass to make a final product, capacities of these machines ranges from 1000 to 2000 lb/hr.
6. Separation of mixture using flotation depends up on ___
Answer: b [Reason:] Separation of a mixture depends up on the difference in the surface properties of the materials involved in separation.
7. What agent can hold the particle on the fluid surface?
a) Hold agent
b) Bubble agent
c) Grignard’s reagent
d) Forth agent
Answer: d [Reason:] If a suitable frothing agent is added to the liquid, the particles will be held on the surface by means of the forth.
8. _____ can increase the angle of contact.
Answer: a [Reason:] The affinity of particle should be increased towards the fluid these can be done by increasing the angle of contact by adding suitable promoters.
9. Which of the following is a known promoter?
a) Sodium ethyl Xanthate
b) Caustic soda
c) Soda Ash
Answer: a [Reason:] A commonly used promoter is sodium ethyl xanthate has the formula Na(S) COC2H5, and
structure shown below.
10. In sodium ethyl Xanthate, the Xanthate ions are ____
a) Positively charged
b) Negatively charged
d) Van der Waal forces
Answer: b [Reason:] In solution this material ionizes giving negatively charged Xanthate ions, the polar end of Xanthate ions is absorbed on new surface.