The percentage of free space in a body-centered cubic unit cell is:

1. 30%
2. 32%
3. 34%
4. 28%
Subtopic:  Density & Packing Fraction |
87%
From NCERT
AIPMT - 2008
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The correct order of the packing efficiency in different types of unit cells is-

1.  Fcc < Bcc < Simple cubic

2.  Fcc > Bcc > Simple cubic

3.  Fcc < Bcc > Simple cubic

4.  Bcc < Fcc > Simple cubic

Subtopic:  Density & Packing Fraction |
86%
From NCERT
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The packing efficiency of the face-centered cubic unit cell is:
(assuming that the atoms are touching each other)

1. 52.40 %

2. 68.04 %

3. 74 %

4. 79.06 %

Subtopic:  Density & Packing Fraction |
85%
From NCERT
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The relation between the atomic mass of unknown metal with density and the dimension of its unit cell is given by  :

(Given: All the cell edge lengths are equal)

1. $$m \ = \ \frac{\rho a^{3}N_{A}}{Z}$$
2. $$m \ = \ \rho a^{3}N_{A}Z$$
3. $$m \ = \ \frac{Z}{\rho a^{3}N_{A}}$$
4. $$m \ = \ \frac{ZN_{A}}{a^{3}\rho}$$

Subtopic:  Density & Packing Fraction |
84%
From NCERT
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The most efficient packing is present in -

1. HCP and BCC

2. HCP and CCP

3. BCC and CCP

4. BCC and Simple cubic cell

Subtopic:  Density & Packing Fraction |
82%
From NCERT
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Silver crystallizes in fcc lattice. If the edge length of the cell is 4.07 × 10−8 cm and density is 10.5 g cm−3, the atomic mass of silver is -

1. 120.31 g ${\mathrm{mol}}^{-1}$

2. 107.9 g ${\mathrm{mol}}^{-1}$

3. 207.60 g ${\mathrm{mol}}^{-1}$

4. 138.52 g ${\mathrm{mol}}^{-1}$

Subtopic:  Density & Packing Fraction |
81%
From NCERT
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The fraction of total volume occupied by the atoms present in a simple cube is:

1. $\frac{\mathrm{\pi }}{6}$

2. $\frac{\mathrm{\pi }}{3\sqrt{2}}$

3. $\frac{\mathrm{\pi }}{4\sqrt{2}}$

4. $\frac{\mathrm{\pi }}{4}$

Subtopic:  Density & Packing Fraction |
81%
From NCERT
AIPMT - 2007
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An element has a body-centered cubic (BCC) structure with a cell edge of 288 pm. The atomic radius is:

1. $\frac{\sqrt{2}}{4}×288$ pm

2. $\frac{4}{\sqrt{3}}×288$ pm

3. $\frac{4}{\sqrt{2}}×288$ pm

4. $\frac{\sqrt{3}}{4}×288$ pm

Subtopic:  Introduction & Crystal System | Density & Packing Fraction |
81%
From NCERT
NEET - 2020
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A given metal crystallizes out with a cubic structure having an edge length of 361 pm. If there are four metal atoms in one unit cell, the radius of one atom is:

1. 40 pm
2. 127 pm
3. 80 pm
4. 108 pm

Subtopic:  Density & Packing Fraction |
76%
From NCERT
NEET - 2015
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An element with a molar mass of 2.7 × 10-2 kg mol-1  and density  2.7 × 103 kg m-3  forms a unit cell with an edge length of 405 pm. The type of unit cell is-

1. Simple cubic cell.

2. Face-centered cubic cell.

3. Body-centered cubic cell.

4. None of the above.

Subtopic:  Density & Packing Fraction |
77%
From NCERT
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