Question 1

When a p-n junction diode is forward biased

Accepted Answer

A) a current does not flow through it. 
B) a current flows through it from the p-side to the n-side. 
C) a current flows through it from the n-side to the p-side. 
D) a current flows because holes and electrons are traveling in opposite directions away from the junction. 
E) a current flows because holes and electrons are traveling in the same direction towards the junction. 
A) a current does not flow through it. 
B) a current flows through it from the p-side to the n-side. 
C) a current flows through it from the n-side to the p-side. 
D) a current flows because holes and electrons are traveling in opposite directions away from the junction. 
E) a current flows because holes and electrons are traveling in the same direction towards the junction.

Question 2

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) 3.6 eV 
B) 0.45 eV 
C) 2.0 eV 
D) 3.1 eV 
E) 1.0 eV 
A) 3.6 eV 
B) 0.45 eV 
C) 2.0 eV 
D) 3.1 eV 
E) 1.0 eV

Question 3

A diatomic quantum mechanical oscillator has a moment of inertia of 7.73 × 10-45 kg∙m2. What is the rotational energy in the quantum state characterized by L = 2?

Accepted Answer

A) 2.27 × 10-5 eV 
B) 2.72 × 10-5 eV 
C) 5.87 × 10-5 eV 
D) 7.22 × 10-5 eV 
E) 8.71 × 10-5 eV 
A) 2.27 × 10-5 eV 
B) 2.72 × 10-5 eV 
C) 5.87 × 10-5 eV 
D) 7.22 × 10-5 eV 
E) 8.71 × 10-5 eV

Question 4

For a diatomic quantum mechanical rotator, the energy difference between adjacent energy levels

Accepted Answer

A) increases as L increases. 
B) decreases as L increases. 
C) is constant for all L. 
D) varies randomly as L increases. 
A) increases as L increases. 
B) decreases as L increases. 
C) is constant for all L. 
D) varies randomly as L increases.

Question 5

In the potential energy diagram of a molecule, the activation energy is the energy that is

Accepted Answer

A) necessary to get the molecule to form. 
B) above the ground state of the molecule. 
C) released when the molecule is formed. 
D) stored in the molecule. 
E) at the ground state of the molecule. 
A) necessary to get the molecule to form. 
B) above the ground state of the molecule. 
C) released when the molecule is formed. 
D) stored in the molecule. 
E) at the ground state of the molecule.

Question 6

If the potential energy diagram, when shown as a function of the separation of the atoms in the molecule, has a positive slope, then the force between the atoms

Accepted Answer

A) has the highest possible value. 
B) is attractive. 
C) has the lowest possible value. 
D) is repulsive. 
E) is none of the above. 
A) has the highest possible value. 
B) is attractive. 
C) has the lowest possible value. 
D) is repulsive. 
E) is none of the above.

Question 7

An unfilled electron state in the valence band is called

Accepted Answer

A) a hole. 
B) an empty electron. 
C) a conduction electron. 
D) a positron. 
E) an empty positron. 
A) a hole. 
B) an empty electron. 
C) a conduction electron. 
D) a positron. 
E) an empty positron.

Question 8

Silver has a Fermi level of 5.5 eV. At 0 K, what is the speed of the electrons with the Fermi speed?

Accepted Answer

A) 1.4 × 106 m/s 
B) 1100 m/s 
C) 2200 m/s 
D) 0 
E) 1.1 × 106 m/s 
A) 1.4 × 106 m/s 
B) 1100 m/s 
C) 2200 m/s 
D) 0 
E) 1.1 × 106 m/s

Question 9

Which of the following statements is true?

Accepted Answer

A) In a p-type doped semiconductor the donor level is close to the valence band. 
B) In an n-type doped semiconductor the acceptor level is close to the valence band. 
C) In a p-type doped semiconductor the acceptor level is close to the valence band. 
D) In an n-type doped semiconductor the donor level is close to the valence band. 
E) None of the statements are true. 
A) In a p-type doped semiconductor the donor level is close to the valence band. 
B) In an n-type doped semiconductor the acceptor level is close to the valence band. 
C) In a p-type doped semiconductor the acceptor level is close to the valence band. 
D) In an n-type doped semiconductor the donor level is close to the valence band. 
E) None of the statements are true.

Question 10

For a diatomic quantum mechanical vibrator, the energy difference between adjacent quantum states

Accepted Answer

A) increases as v increases. 
B) decreases as v increases. 
C) is constant for all values of v. 
D) varies randomly as v increases. 
A) increases as v increases. 
B) decreases as v increases. 
C) is constant for all values of v. 
D) varies randomly as v increases.

Question 11

The spacing of the atoms in the H2 molecule is 7.4 x 10-11 m. What is the moment of inertia of this molecule about its center of mass?

Accepted Answer

A) 1.5 x 10-47 kg∙ m2 
B) 1.9 x 10-47 kg∙ m2 
C) 9.1 x 10-48 kg∙ m2 
D) 4.6 x 10-48 kg∙ m2 
E) 2.3 x 10-48 kg∙v 
A) 1.5 x 10-47 kg∙ m2 
B) 1.9 x 10-47 kg∙ m2 
C) 9.1 x 10-48 kg∙ m2 
D) 4.6 x 10-48 kg∙ m2 
E) 2.3 x 10-48 kg∙v

Question 12

A p-type semiconductor has a net positive charge.

Accepted Answer

A) True 
 B)False

Question 13

The bond energy for a hydrogen molecule is

Accepted Answer

A) 1.5 eV. 
B) 2.5 eV. 
C) 3.5 eV. 
D) 4.5 eV. 
E) 5.5 eV. 
A) 1.5 eV. 
B) 2.5 eV. 
C) 3.5 eV. 
D) 4.5 eV. 
E) 5.5 eV.

Question 14

A diatomic quantum mechanical rotator in the L = 1 quantum state has energy E. The same rotator in the L = 2 quantum state will have energy

Accepted Answer

A) 2E. 
B) 3E. 
C) 6E. 
D) 8E. 
E) none of the given answers 
A) 2E. 
B) 3E. 
C) 6E. 
D) 8E. 
E) none of the given answers

Question 15

An n-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.

Question 16

Van der Waals bonding is caused by

Accepted Answer

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

Exam 40: Molecules and Solids

When a p-n junction diode is forward biased

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?

A diatomic quantum mechanical oscillator has a moment of inertia of 7.73 × 10-45 kg∙m2. What is the rotational energy in the quantum state characterized by L = 2?

For a diatomic quantum mechanical rotator, the energy difference between adjacent energy levels

In the potential energy diagram of a molecule, the activation energy is the energy that is

If the potential energy diagram, when shown as a function of the separation of the atoms in the molecule, has a positive slope, then the force between the atoms

An unfilled electron state in the valence band is called

Silver has a Fermi level of 5.5 eV. At 0 K, what is the speed of the electrons with the Fermi speed?

Which of the following statements is true?

For a diatomic quantum mechanical vibrator, the energy difference between adjacent quantum states

The spacing of the atoms in the H2 molecule is 7.4 x 10-11 m. What is the moment of inertia of this molecule about its center of mass?

A p-type semiconductor has a net positive charge.

The bond energy for a hydrogen molecule is

A diatomic quantum mechanical rotator in the L = 1 quantum state has energy E. The same rotator in the L = 2 quantum state will have energy

An n-type semiconductor is produced by

Van der Waals bonding is caused by

Introduction, Measurement, Estimating

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Filters

A diatomic quantum mechanical oscillator has a moment of inertia of 7.73 × 10^-⁴⁵ kg∙m². What is the rotational energy in the quantum state characterized by L = 2?

The spacing of the atoms in the H₂ molecule is 7.4 x 10^-11 m. What is the moment of inertia of this molecule about its center of mass?