Packing Fraction and Efficiency

Q.

The calculation of packing fraction is useful to get an idea of which of the following?

1. Density of the spheres.

2. Volume of the unit cell.

3. Distance between spheres.

4. How tightly the spheres are arranged.

Q.

What you mean by packing fraction in 3D?

1. Space in the unit cell

2. Density of particles/Density of cell.

3. Space occupied by particles/ Total volume of cell.

4. Volume of unit cell

Q.

Let's take a Rubik's cube.

We know that a Rubik's cube is made up of 27 identical smaller cubes which make up one large cube as seen in the picture above.

Let us assume that the one of the small cubes is missing. What will be the packing fraction in this case?

1. 0

2. 1/27

3. 1

4. 26/27

Q. A compound of formula $A_2{B}_3$ has the hcp lattice.
Which atom forms the $hcp$ lattice and what fraction of tetrahedral voids is occupied by the other atoms?

1. $hcp$ lattice $-B,\frac{2}{3}rd$ Tetrahedral voids $-A$
2. $hcp$ lattice $-A,\frac{2}{3}rd$ Tetrahedral voids $-B$
3. $hcp$ lattice $-A,\frac{1}{3}rd$ Tetrahedral voids $-B$
4. $hcp$ lattice $-B,\frac{1}{3}rd$ Tetrahedral voids $-A$

Q.

Calculate packing fraction in the following case to two decimal places. All circles are of equal radius.

Multiply the answer by 100 and enter the value.

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Q.

Calculate packing fraction from the following figure to two decimal places. Multiply it by 100 and enter the value.

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Q.

Fraction of total volume occupied by atoms in a simple cubic cell is

1. 
   

2. 
   

3. 
   

4. 
   

Q.

What will be the packing fraction in the following case?

The sphere is touching the sides of the cube exactly.

1. pi/3

2. pi/4

3. pi/6

4. pi/2

Q.

Packing fraction is minimum in which of the following?

1. Face Centre Cubic

2. Body Centre Cubic

3. Simple Cubic Close packing

4. Hexagonal Close Packing

Q.

We have a cube as follows which has a sphere inside in the following two ways:

Assume that the cube and sphere are identical in both cases.

Is the packing fraction different in these two cases?

1. yes

2. Could be

3. No

4. I don't know