This chapter is currently out of syllabus
1
COMEDK 2021
MCQ (Single Correct Answer)
+1
-0
Out of Syllabus

Sodium metal crystallises in a body centred cubic lattice with a unit cell edge of 4.29 $$\mathop A\limits^o $$. The radius of sodium atom is

A
1.86 $$\mathop A\limits^o $$
B
3.22 $$\mathop A\limits^o $$
C
5.72 $$\mathop A\limits^o $$
D
0.93 $$\mathop A\limits^o $$
2
COMEDK 2021
MCQ (Single Correct Answer)
+1
-0
Out of Syllabus

How much part of any corner atom actually belongs to a particular unit cell?

A
$$\frac{1}{4}$$th
B
$$\frac{1}{6}$$th
C
$$\frac{1}{8}$$th
D
$$\frac{1}{10}$$th
3
COMEDK 2021
MCQ (Single Correct Answer)
+1
-0
Out of Syllabus

The vacant space in bcc lattice cell is

A
26%
B
48%
C
23%
D
32%
4
COMEDK 2020
MCQ (Single Correct Answer)
+1
-0
Out of Syllabus

Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that, graphite

A
has molecules of variable molecular masses like polymers.
B
has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds.
C
is a non-crystalline substance.
D
is an allotropic form of carbon.
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