33. Distance covered by the Fermi sphere of a face-centered cubic crystal of side’
a’ towards the center of the zone face is:
(a) 90%
(b) 80%
(c) 70%
(d) 60%
34. The radius of the Fermi sphere for a face-centered cubic crystal of side “a” is
separated from the zone boundary by a distance of:
(a) 3:169
p
a
À Á
(b) 2:169
p
a
À Á
(c) 1:169
p
a
À Á
(d) 0:169
p
a
À Á
35. The radius of the Fermi sphere of bcc tetragonal crystal with (c/a) = 2 is:
(a) 0.985p
(b) 0.885p
(c) 0.785p
(d) 0.685p
Answers
1. (c)
2. (d)
3. (c)
4. (d)
5. (b)
6. (a)
7. (d)
8. (a)
9. (a)
10. (b)
11. (a)
12. (c)
13. (b)
14. (a)
15. (c)
16. (b)
17. (b)
18. (a)
19. (a)
20. (b)
21. (c)
22. (d)
2.4 Fermi Surface and Brillouin Zone
93