Question 1

An acceptor replacement atom in silicon might have ______ electrons in its outer shell.

Accepted Answer

A)  3 
B)  4 
C)  5 
D)  6 
E)  7 
A)  3 
B)  4 
C)  5 
D)  6 
E)  7

Question 2

At room temperature, kT is about 0.0259 eV. The probability that a state 0.50 eV below the Fermi level is unoccupied at room temperature is:

Accepted Answer

A)  1 
B)  0.05 
C)  0.026 
D)  5.0 * 10-6 
E)  4.1 * 10-9 
A)  1 
B)  0.05 
C)  0.026 
D)  5.0 * 10-6 
E)  4.1 * 10-9

Question 3

A certain material has a resistivity of 7.8 *103  $\Omega$.m at room temperature, and its resistivity increases as the temperature is raised by 100$\degree$C. The material is most likely:

Accepted Answer

A)  a metal 
B)  a pure semiconductor 
C)  a heavily doped semiconductor 
D)  an insulator 
E)  none of the above 
A)  a metal 
B)  a pure semiconductor 
C)  a heavily doped semiconductor 
D)  an insulator 
E)  none of the above

Question 4

Which one of the following statements concerning electron energy bands in solids is true?

Accepted Answer

A)  the bands occur as a direct consequence of the Fermi-Dirac distribution function 
B)  electrical conduction arises from the motion of electrons in completely filled 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 filled band and the lowest empty band 
E)  only insulators have energy bands 
A)  the bands occur as a direct consequence of the Fermi-Dirac distribution function 
B)  electrical conduction arises from the motion of electrons in completely filled 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 filled band and the lowest empty band 
E)  only insulators have energy bands

Question 5

The speed of an electron with energy equal to the Fermi energy for copper is on the order of:

Accepted Answer

A)  10-6 m/s 
B)  10-1 m/s 
C)  10 m/s 
D)  106 m/s 
E)  109 m/s 
A)  10-6 m/s 
B)  10-1 m/s 
C)  10 m/s 
D)  106 m/s 
E)  109 m/s

Question 6

Application of a forward bias to a p-n junction:

Accepted Answer

A)  narrows the depletion zone 
B)  increases the electric field in the depletion zone 
C)  increases the potential difference across the depletion zone 
D)  increases the number of donors on the n side 
E)  decreases the number of donors on the n side 
A)  narrows the depletion zone 
B)  increases the electric field in the depletion zone 
C)  increases the potential difference across the depletion zone 
D)  increases the number of donors on the n side 
E)  decreases the number of donors on the n side

Question 7

Which of the following is NOT true when a back bias is applied to a p-n junction?

Accepted Answer

A)  Electrons flow from the p to the n side 
B)  Holes flow from the p to the n side 
C)  The electric field in the depletion zone increases 
D)  The potential difference across the depletion zone increases 
E)  The depletion zone narrows 
A)  Electrons flow from the p to the n side 
B)  Holes flow from the p to the n side 
C)  The electric field in the depletion zone increases 
D)  The potential difference across the depletion zone increases 
E)  The depletion zone narrows

Question 8

If E0 and ET are the average energies of the "free" electrons in a metal at 0 K and room temperature respectively, then the ratio ET/E0 is approximately:

Accepted Answer

A)  0 
B)  1 
C)  100 
D)  106 
E)  infinity 
A)  0 
B)  1 
C)  100 
D)  106 
E)  infinity

Question 9

The energy level diagram shown applies to:

Accepted Answer

A)  a conductor 
B)  an insulator 
C)  a semiconductor 
D)  an isolated molecule 
E)  an isolated atom 
A)  a conductor 
B)  an insulator 
C)  a semiconductor 
D)  an isolated molecule 
E)  an isolated atom

Question 10

A given doped semiconductor can be identified as p or n type by:

Accepted Answer

A)  measuring its electrical conductivity 
B)  measuring its magnetic susceptibility 
C)  measuring its coefficient of resistivity 
D)  measuring its heat capacity 
E)  performing a Hall effect experiment 
A)  measuring its electrical conductivity 
B)  measuring its magnetic susceptibility 
C)  measuring its coefficient of resistivity 
D)  measuring its heat capacity 
E)  performing a Hall effect experiment

Question 11

The energy level diagram shown applies to:

Accepted Answer

A)  a conductor 
B)  an insulator 
C)  a semiconductor 
D)  an isolated molecule 
E)  an isolated atom 
A)  a conductor 
B)  an insulator 
C)  a semiconductor 
D)  an isolated molecule 
E)  an isolated atom

Exam 41: Conduction of Electricity in Solids

An acceptor replacement atom in silicon might have ______ electrons in its outer shell.

At room temperature, kT is about 0.0259 eV. The probability that a state 0.50 eV below the Fermi level is unoccupied at room temperature is:

A certain material has a resistivity of 7.8 *103 Ω\OmegaΩ .m at room temperature, and its resistivity increases as the temperature is raised by 100 °\degree° C. The material is most likely:

Which one of the following statements concerning electron energy bands in solids is true?

The speed of an electron with energy equal to the Fermi energy for copper is on the order of:

Application of a forward bias to a p-n junction:

Which of the following is NOT true when a back bias is applied to a p-n junction?

If E0 and ET are the average energies of the "free" electrons in a metal at 0 K and room temperature respectively, then the ratio ET/E0 is approximately:

The energy level diagram shown applies to:

A given doped semiconductor can be identified as p or n type by:

The energy level diagram shown applies to:

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A certain material has a resistivity of 7.8 *10³ $\Omega$ .m at room temperature, and its resistivity increases as the temperature is raised by 100 $\degree$ C. The material is most likely:

If E₀ 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/E₀ is approximately: