Callister - An introduction - 8th edition

774 • Chapter 18 / Electrical Properties
REFERENCES
Bube, R. H., Electrons in Solids, 3rd edition, Academic
Press, San Diego, 1992.
Hummel, R. E., Electronic Properties of Materials,
3rd edition, Springer-Verlag, New York, 2000.
Irene, E. A., Electronic Materials Science, Wiley,
Hoboken, NJ, 2005.
Jiles, D. C., Introduction to the Electronic Properties
of Materials, 2nd edition, Nelson Thornes,
Cheltenham, UK, 2001.
Kingery, W. D., H. K. Bowen, and D. R. Uhlmann,
Introduction to Ceramics, 2nd edition, Wiley,
New York, 1976. Chapters 17 and 18.
Kittel, C., Introduction to Solid State Physics, 8th
edition, Wiley, Hoboken, NJ, 2005. An advanced
treatment.
Livingston, J., Electronic Properties of Engineering
Materials, Wiley, New York, 1999.
Pierret, R. F., Semiconductor Device Fundamentals,
Addison-Wesley, Boston, 1996.
Rockett, A., The Materials Science of Semiconductors,
Springer, New York, 2008.
Solymar, L., and D. Walsh, Electrical Properties of
Materials, 7th edition, Oxford University Press,
New York, 2004.
QUESTIONS AND PROBLEMS
Ohm’s Law
Electrical Conductivity
18.1 (a) Compute the electrical conductivity of a
5.1-mm- (0.2-in.-) diameter cylindrical silicon
specimen 51 mm (2 in.) long in which a current
of 0.1 A passes in an axial direction. A
voltage of 12.5 V is measured across two
probes that are separated by 38 mm (1.5 in.).
(b) Compute the resistance over the entire
51 mm (2 in.) of the specimen.
18.2 A copper wire 100 m long must experience a
voltage drop of less than 1.5 V when a current
of 2.5 A passes through it. Using the data in
Table 18.1, compute the minimum diameter
of the wire.
18.3 An aluminum wire 4 mm in diameter is to
offer a resistance of no more than 2.5 . Using
the data in Table 18.1, compute the maximum
wire length.
18.4 Demonstrate that the two Ohm’s law expressions,
Equations 18.1 and 18.5, are equivalent.
18.5 (a) Using the data in Table 18.1, compute the
resistance of a copper wire 3 mm (0.12 in.) in
diameter and 2 m (78.7 in.) long.(b)What would
be the current flow if the potential drop across
the ends of the wire is 0.05 V? (c) What is the
current density? (d) What is the magnitude of
the electric field across the ends of the wire?
Electronic and Ionic Conduction
18.6 What is the distinction between electronic
and ionic conduction?
Energy Band Structures in Solids
18.7 How does the electron structure of an
isolated atom differ from that of a solid
material?
Conduction in Terms of Band and
Atomic Bonding Models
18.8 In terms of electron energy band structure,
discuss reasons for the difference in electrical
conductivity between metals, semiconductors,
and insulators.
Electron Mobility
18.9 Briefly tell what is meant by the drift velocity
and mobility of a free electron.
18.10 (a) Calculate the drift velocity of electrons
in germanium at room temperature and
when the magnitude of the electric field is
1000 V/m. (b) Under these circumstances,
how long does it take an electron to traverse
a 25-mm (1-in.) length of crystal?
18.11 At room temperature the electrical conductivity
and the electron mobility for copper
are 6.0 10 7 (#
m) 1 and 0.0030 m 2 /V#
s, respectively.
(a) Compute the number of free
electrons per cubic meter for copper at room
temperature. (b) What is the number of free
electrons per copper atom? Assume a density
of 8.9 g/cm 3 .
18.12 (a) Calculate the number of free electrons
per cubic meter for gold, assuming that
there are 1.5 free electrons per gold atom.