# ch41 - Chapter 41 CONDUCTION OF ELECTRICITY IN SOLIDS 1 In...

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Unformatted text preview: Chapter 41: CONDUCTION OF ELECTRICITY IN SOLIDS 1. In a pure metal the collisions that are characterized by the mean free time τ in the expression for the resistivity are chie f y between: A. electrons and other electrons B. electrons with energy about equal to the Fermi energy and atoms C. all electrons and atoms D. electrons with energy much less than the Fermi energy and atoms E. atoms and other atoms ans: B 2. A certain metal has 5 . 3 × 10 29 conduction electrons/m 3 and an electrical resistivity of 1 . 9 × 10 − 9 Ω · m. The average time between collisions of electrons with atoms in the metal is: A. 5 . 6 × 10 − 33 s B. 1 . 3 × 10 − 31 s C. 9 . 9 × 10 − 22 s D. 4 . 6 × 10 − 15 s E. 3 . 5 × 10 − 14 s ans: C 3. Which one of the following statements concerning electron energy bands in solids is true? A. The bands occur as a direct consequence of the Fermi-Dirac occupancy probability function B. Electrical conduction arises from the motion of electrons in completely F lled bands C. Within a given band, all electron energy levels are equal to each other D. An insulator has a large energy separation between the highest F lled band and the lowest empty band E. Only insulators have energy bands ans: D 4. If E and E T are the average energies of the “free” electrons in a metal at 0 K and room temperature, respectively, then the ratio E T /E is approximately: A. 0 B. 1 C. 100 D. 10 6 E. in F nity ans: B 5. The energy gap (in eV) between the valence and conduction bands of an insulator is of the order of: A. 10 − 19 B. 0 . 001 C. 0 . 1 D. 10 E. 1000 ans: D 612 Chapter 41: CONDUCTION OF ELECTRICITY IN SOLIDS 6. The energy level diagram shown applies to: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . un f lled: . . . . . . ....
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## This note was uploaded on 04/14/2008 for the course PHYSICS 108 taught by Professor Halstead during the Spring '08 term at SUNY Buffalo.

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ch41 - Chapter 41 CONDUCTION OF ELECTRICITY IN SOLIDS 1 In...

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