# Mechanical Operations Questions and Answers – Ultra-Fine Grinders

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This set of Mechanical Operations Multiple Choice Questions & Answers (MCQs) focuses on “Ultra-Fine Grinders”.

1. Jigging involves ______
a) Pulsation
b) Vibration
c) Shaking
d) Digging

Explanation: Jigging is one of the oldest method used for processing heavy minerals from light ones by pulsation of stream of liquid flowing through a bed of materials.

2. Jigging is best suited for ___
a) Drag materials
b) Fine materials
c) Coarse materials
d) Higher materials

Explanation: Jigging is best suited for coarse material that is in the size range of 20 mesh and coarser where it is considerable difference between specific gravity.

3. What are the dimensions of a jig?
a) 5 by 16 ft
b) 10 by 18 ft
c) 20 by 30 ft
d) 5 by 5 ft

Explanation: The standard dimensions of a jig are 5 by 16 feet’s, and will treat minus 3/8 inch ore at a rate of 30 to 45 T/hr.

4. Separation by flowing pulp is achieved in _____ process.
a) Jigging
b) Tabling
c) Drilling
d) Raking

Explanation: Tabling is a concentration process whereby a separation between two or more materials is affected by flowing pulp across the material.

5. Wilfley rifled tables are used for _____
a) 5 to 100 mesh size
b) 1 to 5 mesh size
c) 6 to 150 mesh size
d) 20 to 200 mesh size

Explanation: Wilfley tables are effectively used in the size range of 6 to 150 mesh but can be used to treat light materials of a considerable size.

6. How are particles classified magnetically?
a) Dia and Para magnetic
b) Bi and Pseudo magnetic
c) Half and full magnetic
d) Kinch and lynch magnetic

Explanation: Solid may be classified into two broad categories as Diamagnetic and Paramagnetic, any solid placed in a magnetic field is affected by it somehow.

7. Solids which are repelled by a magnet are called ____
a) HI magnetic
b) Short magnetic
c) Paramagnetic
d) Diamagnetic

Explanation: Diamagnetic materials are repelled by a magnetic field, the applied magnetic field creates a magnetic field in them in the reverse direction, causing a repulsion.

8. Solids which are attracted by a magnet are called ____
a) Full magnetic
b) Short magnetic
c) Paramagnetic
d) Diamagnetic

Explanation: Para magnetism is whereby certain materials are attracted by an externally applied magnetic field, it induces magnetic fields in the same direction of magnetic field.

9. The higher the magnetic field, the higher the ___
a) Separation
b) Unwanted particles
c) Flow
d) Current

Explanation: Inducing a higher magnetic field results in a higher number of separation from the bulk materials, this also increases the power requirement.

10. On what speed does the electromagnetic pulley operates?
a) 100 ft. /min
b) 680 ft. /min
c) 500 ft. /min
d) 700 ft. /min

Explanation: Electromagnetic pulleys are primarily obtained at a belt speed of 500 ft./min, if a higher speed is required then pulley of larger diameter is selected.

Sanfoundry Global Education & Learning Series – Mechanical Operations.

To practice all areas of Mechanical Operations, here is complete set of 1000+ Multiple Choice Questions and Answers.