Question 1

A p-type semiconductor is produced by

Accepted Answer

A) doping the host crystal with donor impurities. 
B) doping the host crystal with accepter impurities. 
C) pure crystals of germanium. 
D) all of the above. 
E) none of the above. 
A) doping the host crystal with donor impurities. 
B) doping the host crystal with accepter impurities. 
C) pure crystals of germanium. 
D) all of the above. 
E) none of the above. B

Question 2

A diatomic quantum mechanical vibrator in its ground state has energy E. This same vibrator in its third state has energy

Accepted Answer

A) E. 
B) 3E. 
C) 5E. 
D) 7E. 
E) 9E. 
A) E. 
B) 3E. 
C) 5E. 
D) 7E. 
E) 9E. C

Question 3

Approximately how many states in the range from 5.0 eV to 5.2 eV are there in a copper bar of volume 5.3   ?

Accepted Answer

A) 5.1 x 1022 
B) 3.2 x 1022 
C) 1.6 x 1022 
D) 8.2 x 1021 
E) 3.2 x 1021 
A) 5.1 x 1022 
B) 3.2 x 1022 
C) 1.6 x 1022 
D) 8.2 x 1021 
E) 3.2 x 1021 C

Question 4

The conductivity of a semiconductor sharply increases when 400 nm (or shorter) wavelength light is shone upon it. This is consistent with what energy gap for this material?

Accepted Answer

A) 5.2 eV 
B) 3.6 eV 
C) 3.1 eV 
D) 1.0 eV 
E) 0.45 eV 
A) 5.2 eV 
B) 3.6 eV 
C) 3.1 eV 
D) 1.0 eV 
E) 0.45 eV

Question 5

The spacing of the atoms in the H2 molecule is 7.4 x 10-11 m. What is the energy of the L = 1 rotational level?

Accepted Answer

A) 9.0 x 10-2 eV 
B) 7.0 x 10-2 eV 
C) 4.5 x 10-2 eV 
D) 3.0 x 10-2 eV 
E) 1.5 x 10-2 eV 
A) 9.0 x 10-2 eV 
B) 7.0 x 10-2 eV 
C) 4.5 x 10-2 eV 
D) 3.0 x 10-2 eV 
E) 1.5 x 10-2 eV

Question 6

If one metal has double the number of conduction electrons per unit volume of a second metal, then its Fermi level is how many times that of the second metal?

Accepted Answer

A) 1.41 
B) 2.83 
C) 2.00 
D) 3.22 
E) 1.59 
A) 1.41 
B) 2.83 
C) 2.00 
D) 3.22 
E) 1.59

Question 7

Ionic bonding is caused by

Accepted Answer

A) the sharing of electrons between atoms. 
B) the transfer of electrons between atoms. 
C) unequal charge distributions around neutral molecules. 
D) atoms bonding to hydrogen molecules. 
E) atoms bonding to oxygen molecules. 
A) the sharing of electrons between atoms. 
B) the transfer of electrons between atoms. 
C) unequal charge distributions around neutral molecules. 
D) atoms bonding to hydrogen molecules. 
E) atoms bonding to oxygen molecules.

Question 8

The Fermi level of a metal is 5.5 eV. What is the number of conduction electrons per unit volume for this metal?

Accepted Answer

A) 5.8 × 1028/m3 
B) 6.2 × 1028/ m3 
C) 4.1 × 1028/ m3 
D) 8.4 × 1028/ m3 
E) N/V does not depend on   
A) 5.8 × 1028/m3 
B) 6.2 × 1028/ m3 
C) 4.1 × 1028/ m3 
D) 8.4 × 1028/ m3 
E) N/V does not depend on

Question 9

In a good insulator, the highest energy band containing electrons, called the valence band, is

Accepted Answer

A) only partially filled. 
B) completely filled. 
A) only partially filled. 
B) completely filled.

Question 10

A metal has a Fermi level of 5.50 eV. At 1200 K, what energy will have a 90% occupancy probability?

Accepted Answer

A) 5.79 eV 
B) 5.73 eV 
C) 5.56 eV 
D) 5.44 eV 
E) 5.27 eV 
A) 5.79 eV 
B) 5.73 eV 
C) 5.56 eV 
D) 5.44 eV 
E) 5.27 eV

Question 11

The potential energy for the formation of a hydrogen molecule can be approximated by U = -A + BR + C/R, where R is the nuclear separation. Given that A = -78.5 eV, B = 2.57 × 1011 eV/m , and C = 1.44 × 10-9 eV∙m. At what nuclear separation is the potential energy a minimum?

Accepted Answer

A) 1.9 × 10-11 m 
B) 3.7 × 10-10 m 
C) 7.5 × 10-11 m 
D) 2.9 × 10-11 m 
E) 5.1 × 10-10 m 
A) 1.9 × 10-11 m 
B) 3.7 × 10-10 m 
C) 7.5 × 10-11 m 
D) 2.9 × 10-11 m 
E) 5.1 × 10-10 m

Question 12

A diatomic molecule has 2.6 × 10-5 eV of rotational energy in the L = 2 quantum state. What is the rotational energy in the L = 1 quantum state?

Accepted Answer

A) 3.4 × 10-6 eV 
B) 4.1 × 10-6 eV 
C) 5.3 × 10-6 eV 
D) 7.8 × 10-6 eV 
E) 8.7 × 10-6 eV 
A) 3.4 × 10-6 eV 
B) 4.1 × 10-6 eV 
C) 5.3 × 10-6 eV 
D) 7.8 × 10-6 eV 
E) 8.7 × 10-6 eV

Question 13

A semiconductor has an energy gap of 2.5 eV. What is the longest wavelength light of those listed below that will promote valence electrons into the conduction band?

Accepted Answer

A) 450 nm 
B) 525 nm 
C) 600 nm 
D) 725 nm 
E) 350 nm 
A) 450 nm 
B) 525 nm 
C) 600 nm 
D) 725 nm 
E) 350 nm

Question 14

If the voltage gain for a transistor amplifier is 60 in a circuit with an output resistance of 10,000 ohms, what is the peak output current if the peak input voltage is 0.05 V?

Accepted Answer

A) 3 x 10-4 A 
B) 4 x 10-4 A 
C) 5 x 10-4 A 
D) 6 x 10-4 A 
E) 60 μA 
A) 3 x 10-4 A 
B) 4 x 10-4 A 
C) 5 x 10-4 A 
D) 6 x 10-4 A 
E) 60 μA

Question 15

A diatomic molecule has 18 × 10-5 eV of rotational energy in the L = 2 quantum state. What is the rotational energy in the L = 0 quantum state?

Accepted Answer

A) 9.0 × 10-5 eV 
B) 6.0 × 10-5 eV 
C) 3.0 × 10-5 eV 
D) 1.5 × 10-5 eV 
E) 0 eV 
A) 9.0 × 10-5 eV 
B) 6.0 × 10-5 eV 
C) 3.0 × 10-5 eV 
D) 1.5 × 10-5 eV 
E) 0 eV

Question 16

If a battery is connected to a diode with the positive terminal to the p side and the negative terminal to the n side, then diode is said to be

Accepted Answer

A) forward biased. 
B) reversed biased. 
A) forward biased. 
B) reversed biased.

Question 17

Covalent bonding is caused by

Accepted Answer

A) the sharing of electrons between atoms. 
B) the transfer of electrons between atoms. 
C) unequal charge distributions around neutral molecules. 
D) atoms bonding to hydrogen molecules. 
E) atoms bonding to oxygen molecules. 
A) the sharing of electrons between atoms. 
B) the transfer of electrons between atoms. 
C) unequal charge distributions around neutral molecules. 
D) atoms bonding to hydrogen molecules. 
E) atoms bonding to oxygen molecules.

Question 18

In a p-type semiconductor, a hole is

Accepted Answer

A) a donor atom. 
B) an extra electron supplied by a donor atom. 
C) an extra proton supplied by a donor atom. 
D) a missing atom in the crystalline structure. 
E) a region where an electron is missing. 
A) a donor atom. 
B) an extra electron supplied by a donor atom. 
C) an extra proton supplied by a donor atom. 
D) a missing atom in the crystalline structure. 
E) a region where an electron is missing.

Question 19

What is the occupancy probability at an energy 1.0% above a Fermi level of 7.0 eV at 300 K?

Accepted Answer

A) 0.06% 
B) 1.0% 
C) 3.2% 
D) 6.3% 
E) 12% 
A) 0.06% 
B) 1.0% 
C) 3.2% 
D) 6.3% 
E) 12%

Question 20

What is the occupancy probability at an energy of 12.00 eV for a material with EF = 11.63 eV at a temperature of 500 K?

Accepted Answer

A) 3 x 10-4 % 
B) 2 x 10-2 % 
C) 2% 
D) 6% 
E) 12% 
A) 3 x 10-4 % 
B) 2 x 10-2 % 
C) 2% 
D) 6% 
E) 12%

Exam 40: Molecules and Solids

A p-type semiconductor is produced by

A diatomic quantum mechanical vibrator in its ground state has energy E. This same vibrator in its third state has energy

Approximately how many states in the range from 5.0 eV to 5.2 eV are there in a copper bar of volume 5.3 ?

The conductivity of a semiconductor sharply increases when 400 nm (or shorter) wavelength light is shone upon it. This is consistent with what energy gap for this material?

The spacing of the atoms in the H2 molecule is 7.4 x 10-11 m. What is the energy of the L = 1 rotational level?

If one metal has double the number of conduction electrons per unit volume of a second metal, then its Fermi level is how many times that of the second metal?

Ionic bonding is caused by

The Fermi level of a metal is 5.5 eV. What is the number of conduction electrons per unit volume for this metal?

In a good insulator, the highest energy band containing electrons, called the valence band, is

A metal has a Fermi level of 5.50 eV. At 1200 K, what energy will have a 90% occupancy probability?

The potential energy for the formation of a hydrogen molecule can be approximated by U = -A + BR + C/R, where R is the nuclear separation. Given that A = -78.5 eV, B = 2.57 × 1011 eV/m , and C = 1.44 × 10-9 eV∙m. At what nuclear separation is the potential energy a minimum?

A diatomic molecule has 2.6 × 10-5 eV of rotational energy in the L = 2 quantum state. What is the rotational energy in the L = 1 quantum state?

A semiconductor has an energy gap of 2.5 eV. What is the longest wavelength light of those listed below that will promote valence electrons into the conduction band?

If the voltage gain for a transistor amplifier is 60 in a circuit with an output resistance of 10,000 ohms, what is the peak output current if the peak input voltage is 0.05 V?

A diatomic molecule has 18 × 10-5 eV of rotational energy in the L = 2 quantum state. What is the rotational energy in the L = 0 quantum state?

If a battery is connected to a diode with the positive terminal to the p side and the negative terminal to the n side, then diode is said to be

Covalent bonding is caused by

In a p-type semiconductor, a hole is

What is the occupancy probability at an energy 1.0% above a Fermi level of 7.0 eV at 300 K?

What is the occupancy probability at an energy of 12.00 eV for a material with EF = 11.63 eV at a temperature of 500 K?

Introduction, Measurement, Estimating

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Special Theory of Relativity

Early Quantum Theory and Models of the Atom

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Quantum Mechanics of Atoms

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Filters

The spacing of the atoms in the H₂ molecule is 7.4 x 10^-¹¹ m. What is the energy of the L = 1 rotational level?

The potential energy for the formation of a hydrogen molecule can be approximated by U = -A + BR + C/R, where R is the nuclear separation. Given that A = -78.5 eV, B = 2.57 × 10¹¹eV/m , and C = 1.44 × 10^-9 eV∙m. At what nuclear separation is the potential energy a minimum?

A diatomic molecule has 2.6 × 10^-⁵ eV of rotational energy in the L = 2 quantum state. What is the rotational energy in the L = 1 quantum state?

A diatomic molecule has 18 × 10^-⁵ eV of rotational energy in the L = 2 quantum state. What is the rotational energy in the L = 0 quantum state?

What is the occupancy probability at an energy of 12.00 eV for a material with E_F = 11.63 eV at a temperature of 500 K?