What is the coordination number of a face centered cubic (FCC) unit cell?
8
6
12
4
Answer and explanation
No explanation is available for this question yet.
ObjectiveMcq
Print Protected
This page is protected for print. Use the website to view the content.
86 practice sets · Page 4 of 5
What is the coordination number of a face centered cubic (FCC) unit cell?
8
6
12
4
No explanation is available for this question yet.
What is the coordination number of a simple cubic (SC) unit cell?
6
2
8
4
There are six nearest neighbouring atoms for every atom in a simple cubic (SC) unit cell, in other words, every atom in a SC unit cell is surrounded by 6 other atoms, thus coordination number of SC unit cell is is 6.
Grinding ratio generally lies between
100-200
30-40
0.5-10
1000-200
Grinding ratio = (volume of material removed/volume of wheel wear). G.R is generally between 0.5-10.
Material removal rate in grinding operation is small due to
Due to temperature rise during grinding
Material removal rate does not depend on the rake angle
Positive rake angle
Large portion of abrasives are involved in cutting
Due to the increase in temperature during grinding operation some material get welded again with the chip.
Material removal rate in grinding operation is small due to
Positive rake angle
Only small portion of abrasives are involved in cutting
Material removal rate does not depend on the rake angle
Zero rake angle
Only small portion of abrasives are involved in grinding process and hence has less material removal rate. Hence grinding is mostly use as a finishing process.
Material removal rate in grinding operation is small due to
Negative rake angle
Positive rake angle
Material removal rate does not depend on the rake angle
Zero rake angle
Grinding wheel have negative rake angle and hence have very small material removal rate. Hence grinding is mostly use as a finishing process.
Material removal rate of grinding process in comparison to material removal rate in facing on a lathe is
Small
Large
Can’t say about material removal rate
Same
Material removal rate in grinding process is very small. Hence grinding is mostly use as a finishing process. Only small portion of abrasives are involved in grinding process and hence has less material removal rate.
Which of the following grinding wheel would be more economical for grinding of soft work piece?
Dense structure wheel
Both dense and open structure grinding wheel
Open structure grinding wheel
None of the mentioned
In open structure grinding wheels, during machining of soft work piece material removal rate is large and space for chip flow is also large due to more space between grains of wheel.
Which of the following grinding wheel would be more economical for grinding of hard work piece?
Open structure grinding wheel
Both dense and open structure grinding wheel
None of the mentioned
Dense structure wheel
In dense structure grinding wheels, during machining of hard work piece material removal rate is small and also wheel has good strength.
Which of the following grinding wheel would be more economical for grinding of soft work piece?
Hard grinding wheel
None of the mentioned
Soft grinding wheel
Both hard and soft grinding wheel
In hard grinding wheels, during machining of soft work piece glazing will occur after long time and grains of grinding wheel will be effectively utilized before coming out from the wheel.
Which of the following grinding wheel would be more economical for grinding of hard work piece?
Soft grinding wheel
Hard grinding wheel
None of the mentioned
Both hard and soft grinding wheel
In soft grinding wheels, during machining of hard work piece glazing will occur after long time.
Which of the following will be better to use for machining of soft work piece?
None of the mentioned
Both V and R bond
R-bond
V-bond
Rubber bond grinding wheel is generally used for machining of soft work piece. Fifth place of ISO designation of grinding wheel represents type of bond.
Loss in the sharpness of grinding wheel due to the presence of chips in gaps of grains is termed as
Trueing
Loading
Glazing
Dressing
Loading decrease sharpness of grinding wheel, when foreign material comes in between free space of wheel.
With time, grinding wheel starts rubbing work piece instead of cutting, due to a decrease in sharpness. This phenomenon is known as
Trueing
Dressing
Loading
Glazing
Glazing occurs when grinding wheel starts rubbing work piece instead of cutting.
Friability of grinding wheel is associated to
None of the mentioned
Hardness
Fracture
Size
Friability is the ability to fracture under pressure so that when cutting edge become dull, the grain breaks off and exposes new grains which are sharp.
A grinding wheel is specified as “A 8 K 5 P 17”. Which of the following is correct about this grinding wheel?
Open structure
Rubber bond
Very fine grains
Coarse grain
‘8’ represents grain size, which is coarse.
A grinding wheel is specified as “C 5 K 5 R 17”. Which of the following is correct about this grinding wheel?
Very fine grains
Rubber bond
Coarse grain
Open structure
Fifth place of ISO designation of the grinding wheel represents a type of bond and “R” represents rubber.
A grinding wheel is specified as “A 5 K 5 R 17”. Which of the following is correct about this grinding wheel?
Open structure
Coarse grain
Very fine grains
Aluminum oxide abrasive
First place of ISO designation of the grinding wheel represents grain type and “A” represents aluminum oxide.
A grinding wheel is specified as "C K 8 R 17". Which of the following is correct about this grinding wheel?
Very fine grains
Open structure
Aluminum oxide abrasive
Coarse grain
Fourth place of ISO designation of the grinding wheel represents Structure and “8” comes under open structure.
Which of the following has open structure?
C 8 K 5 3 17
A 80 K 4 B 17
A 46 K 5 B 17
C 600 K 8 B 17
Fourth place of ISO designation of the grinding wheel represents Structure and “8” comes under open structure.