Question 1

If you want to design a phototube that ignores all visible light, what should its cathode's work function be?

Accepted Answer

A)  Below $1.77 \mathrm{eV}$ 
B)  Any value between $1.77 \mathrm{eV}$ and $3.1 \mathrm{eV}$ 
C)  Some specific value between $1.77 \mathrm{eV}$ and $3.1 \mathrm{eV}$ 
D)  Above $3.1 \mathrm{eV}$ 
E)  Some other value or range (specify) 
A)  Below $1.77 \mathrm{eV}$ 
B)  Any value between $1.77 \mathrm{eV}$ and $3.1 \mathrm{eV}$ 
C)  Some specific value between $1.77 \mathrm{eV}$ and $3.1 \mathrm{eV}$ 
D)  Above $3.1 \mathrm{eV}$ 
E)  Some other value or range (specify)

Question 2

(For discussion.) On the basis of the information presented, which do you think is the most plausible resolution of the Collapse Rule's problems? Why?

Accepted Answer

A)  The decoherence model. 
B)  Some modification of the Time Evolution Rule that allows genuine collapse to occur. 
C)  A human mind, which transcends quantum mechanics, is the agent that collapses quantum states. 
D)  Everett's many-worlds proposal. 
E)  The QBist idea that state vectors are not real, but rather only reflect the state of what an observer knows.
F) Something else (describe). 
A)  The decoherence model. 
B)  Some modification of the Time Evolution Rule that allows genuine collapse to occur. 
C)  A human mind, which transcends quantum mechanics, is the agent that collapses quantum states. 
D)  Everett's many-worlds proposal. 
E)  The QBist idea that state vectors are not real, but rather only reflect the state of what an observer knows.
F) Something else (describe).

Question 3

What is -1 expressed as a phase factor?

Accepted Answer

A)  $e^{i \pi / 2}$ 
B)  $e^{-i \pi / 2}$ 
C)  $e^{i \pi}$ 
D)  $e^{i 2 \pi}$ 
E)  Something else (specify) 
A)  $e^{i \pi / 2}$ 
B)  $e^{-i \pi / 2}$ 
C)  $e^{i \pi}$ 
D)  $e^{i 2 \pi}$ 
E)  Something else (specify)

Question 4

The ${ }_{8}^{14} \mathrm{O}$ nucleus is unstable. To what will it decay?

Accepted Answer

A)  ${ }_{7}^{14} \mathbf{N}+\mathbf{e}^{+}+\boldsymbol{v}$ 
B)  ${ }_{7}^{13} \mathrm{~N}+e^{+}+v$ 
C)  ${ }_{7}^{14} \mathrm{~N}+e^{-}+\bar{v}$ 
D)  ${ }_{9}^{14} \mathrm{~N}+e^{+}+v$ 
E)  ${ }_{9}^{14} \mathrm{~F}+e^{-}+\bar{v}$ 
A)  ${ }_{7}^{14} \mathbf{N}+\mathbf{e}^{+}+\boldsymbol{v}$ 
B)  ${ }_{7}^{13} \mathrm{~N}+e^{+}+v$ 
C)  ${ }_{7}^{14} \mathrm{~N}+e^{-}+\bar{v}$ 
D)  ${ }_{9}^{14} \mathrm{~N}+e^{+}+v$ 
E)  ${ }_{9}^{14} \mathrm{~F}+e^{-}+\bar{v}$

Question 5

Imagine that an electron with an initial spin state
$$|\psi\rangle=\left[\begin{array}{l}
\sqrt{1 / 2} \
\sqrt{1 / 2}
\end{array}\right]$$
Goes into an SGz device and comes out the - channel of that device. The electron's spin state is now

Accepted Answer

A)  $\left[\begin{array}{l}\sqrt{1 / 2} \ \sqrt{1 / 2}\end{array}\right]$ 
B)  $\left[\begin{array}{l}-\sqrt{1 / 2} \ -\sqrt{1 / 2}\end{array}\right]$ 
C)  $\left[\begin{array}{l}\sqrt{1 / 2} \ -\sqrt{1 / 2}\end{array}\right]$ 
D)  $\left[\begin{array}{l}1 \ 0\end{array}\right]$ 
E)  $\left[\begin{array}{l}0 \ 1\end{array}\right]$ 
A)  $\left[\begin{array}{l}\sqrt{1 / 2} \ \sqrt{1 / 2}\end{array}\right]$ 
B)  $\left[\begin{array}{l}-\sqrt{1 / 2} \ -\sqrt{1 / 2}\end{array}\right]$ 
C)  $\left[\begin{array}{l}\sqrt{1 / 2} \ -\sqrt{1 / 2}\end{array}\right]$ 
D)  $\left[\begin{array}{l}1 \ 0\end{array}\right]$ 
E)  $\left[\begin{array}{l}0 \ 1\end{array}\right]$

Question 6

With an optically perfect 200-power telescope with a 1.5-inch-diameter tube, you can resolve objects roughly how many times closer together than you could with your naked eye? (Choose the closest answer.)

Accepted Answer

A)  200 times 
B)  100 times 
C)  20 times 
D)  5 times 
E)  No better at all 
A)  200 times 
B)  100 times 
C)  20 times 
D)  5 times 
E)  No better at all

Question 7

For experiments involving the setup shown in figure Q4.1a, which of the following possible results (if seen) about the value displayed by the ammeter would probably not be consistent with the wave model of light?

Accepted Answer

A)  It is zero for some time after light starts shining. 
B)  It increases as the light's intensity increases. 
C)  It varies as the light's wavelength changes. 
D)  It is zero if the wavelength is larger than a certain value. 
A)  It is zero for some time after light starts shining. 
B)  It increases as the light's intensity increases. 
C)  It varies as the light's wavelength changes. 
D)  It is zero if the wavelength is larger than a certain value.

Question 8

Suppose that the tail for a solution to the Schrödinger equation for a given potential energy function is longer in a given classically forbidden region when the energy is $E_{A}$ than that for a solution for energy $E_{B}$. This means that

Accepted Answer

A) $E_{A}>E_{B}$. B) $E_{A}E_{B}$. B) $E_{A}

Question 9

Consider wiggle formula $w(t, x)=f(\mathrm{bx}+\mathrm{ct})$ for a transverse wave, where $b$ and $c$ are constants and $f()$ is some arbitrary function. Is this a traveling wave model? If so, in what direction does it travel?

Accepted Answer

A)  In the $+x$ direction. 
B)  In the $-x$ direction. 
C)  The wave does not move. 
D)  In the $y$ or $z$ direction because the wave is transverse. 
A)  In the $+x$ direction. 
B)  In the $-x$ direction. 
C)  The wave does not move. 
D)  In the $y$ or $z$ direction because the wave is transverse.

Question 10

Suppose we have a box containing an electron with the lowest possible energy $E_{1}$. Imagine that we slowly squeeze the box, making its length $L$ smaller. What will happen to the electron's energy? The system described in problem Q10T. 5 will resist being compressed in the manner described by exerting an opposing force on whatever is compressing it.

Accepted Answer

A) True 
 B)False

Question 11

Line waves with wavelength $\lambda$ going through a slit with width a will be diffracted into circular waves with approximately equal amplitude in all forward directions

Accepted Answer

A)  Always 
B)  Never 
C)  Only if $\lambda \gg>a$ 
D)  Only if $a>>\lambda$ 
E)  Only if $a=\lambda$ 
A)  Always 
B)  Never 
C)  Only if $\lambda \gg>a$ 
D)  Only if $a>>\lambda$ 
E)  Only if $a=\lambda$

Question 12

Which of the state vectors below is not physically equivalent to $|-y\rangle$ ?

Accepted Answer

A)  $\left[\begin{array}{l}-\sqrt{1 / 2} \ i \sqrt{1 / 2}\end{array}\right]$ 
B)  $\left[\begin{array}{l}i \sqrt{1 / 2} \ \sqrt{1 / 2}\end{array}\right]$ 
C)  $\left[\begin{array}{l}-i \sqrt{1 / 2} \ -\sqrt{1 / 2}\end{array}\right]$ 
D)  $\left[\begin{array}{l}e^{i \pi / 6} \sqrt{1 / 2} \ e^{-i \pi / 3} \sqrt{1 / 2}\end{array}\right]$ 
E)  They are all equivalent. 
A)  $\left[\begin{array}{l}-\sqrt{1 / 2} \ i \sqrt{1 / 2}\end{array}\right]$ 
B)  $\left[\begin{array}{l}i \sqrt{1 / 2} \ \sqrt{1 / 2}\end{array}\right]$ 
C)  $\left[\begin{array}{l}-i \sqrt{1 / 2} \ -\sqrt{1 / 2}\end{array}\right]$ 
D)  $\left[\begin{array}{l}e^{i \pi / 6} \sqrt{1 / 2} \ e^{-i \pi / 3} \sqrt{1 / 2}\end{array}\right]$ 
E)  They are all equivalent.

Question 13

Consider a beam of free particles with a certain speed $|\vec{v}|$. If we double this speed, what happens to the beam's de Broglie wavelength?

Accepted Answer

A)  It increases by a factor of 2 . 
B)  It increases by a factor of $2^{1 / 2}$. 
C)  It remains the same. 
D)  It decreases by a factor of $2^{1 / 2}$. 
E)  It decreases by a factor of 2 . 
A)  It increases by a factor of 2 . 
B)  It increases by a factor of $2^{1 / 2}$. 
C)  It remains the same. 
D)  It decreases by a factor of $2^{1 / 2}$. 
E)  It decreases by a factor of 2 .

Question 14

Note: Each problem in this column concerns a quanton moving in one dimension in response to the potential energy function $V(x)$ shown. The graph below the potential energy graph shows the energy eigenfunction (EEF) $\psi_{n}(x)$ corresponding to the energy shown as a horizontal line on the potential energy graph ( $E_{n}$ means the $n$th energy level, where $n=1$ is the ground state). In each case, there is something wrong with the energy eigenfunction shown. Select from the following responses to indicate what is wrong:
The EEF shown is incorrectly drawn because

Accepted Answer

A)  It curves toward the axis in a forbidden region or away from the axis in an allowed region. 
B)  Its wavy part doesn't have the right number of bumps. 
C)  The amplitude of the wavy part varies incorrectly. 
D)  The wavelength of the wavy part varies incorrectly. 
E)  One of the exponential-like tails has the wrong length. 
A)  It curves toward the axis in a forbidden region or away from the axis in an allowed region. 
B)  Its wavy part doesn't have the right number of bumps. 
C)  The amplitude of the wavy part varies incorrectly. 
D)  The wavelength of the wavy part varies incorrectly. 
E)  One of the exponential-like tails has the wrong length.

Question 15

A sound wave traveling in air hits the surface of a body of water. Is the reflected wave (A) inverted or (B) upright? (Make a guess.)

Accepted Answer

A)  Inverted 
B)  Upright 
A)  Inverted 
B)  Upright

Question 16

One detector built to observe solar neutrinos utilized a huge vat of perchloroethylene $\left(\mathrm{CCl}_{2}\right)$ to absorb neutrinos. If a ${ }_{17}^{37} \mathrm{Cl}$ nucleus absorbs a neutrino, what will it become? (Is the product chemically different from chlorine?)

Accepted Answer

A)  ${ }_{17}^{38} \mathrm{Cl}$ 
B)  ${ }_{16}^{37} \mathrm{~S}$ 
C)  ${ }_{18}^{37} \mathrm{Ar}$ 
D)  ${ }_{18}^{38} \mathrm{Ar}$ 
E)  Other (specify) 
A)  ${ }_{17}^{38} \mathrm{Cl}$ 
B)  ${ }_{16}^{37} \mathrm{~S}$ 
C)  ${ }_{18}^{37} \mathrm{Ar}$ 
D)  ${ }_{18}^{38} \mathrm{Ar}$ 
E)  Other (specify)

Question 17

Imagine that sound waves with a certain definite wavelength flow through a partially open sliding door. If the door is closed somewhat further (but not shut entirely), the angle through which the sound waves are diffracted

Accepted Answer

A)  Decreases. 
B)  Increases. 
C)  Remains the same. 
D)  Depends on quantities not specified (explain). 
A)  Decreases. 
B)  Increases. 
C)  Remains the same. 
D)  Depends on quantities not specified (explain).

Question 18

The normal mode of a resonating system is sinusoidally disturbed at a frequency $f$. Assume that $\gamma<<f_{0}$, where $f_{0}$ is the normal mode's natural frequency.
-(b) If $f$ is about $30 f_{0}$ ?

Accepted Answer

A)  Roughly zero 
B)  Roughly $A_{0} / 30$ 
C)  Roughly $A_{0} / 1.4$ 
D)  Roughly $A_{0}$ 
E)  Roughly $1.4 \mathrm{~A}_{0}$
F) Roughly $30 A_{0}$
G) Other (specify) 
A)  Roughly zero 
B)  Roughly $A_{0} / 30$ 
C)  Roughly $A_{0} / 1.4$ 
D)  Roughly $A_{0}$ 
E)  Roughly $1.4 \mathrm{~A}_{0}$
F) Roughly $30 A_{0}$
G) Other (specify)

Question 19

If we shine white light through two slits onto a distant screen, we will see a clear interference pattern.

Accepted Answer

A) True 
 B)False

Question 20

Imagine that we shine a beam of electrons with a de Broglie wavelength of $0.1 \mathrm{~nm}$ through a pair of slits that have been miraculously constructed to be only $10 \mathrm{~nm}$ apart. What will be the order of magnitude of the distance between bright spots of the interference pattern displayed on a fluorescent screen placed $1 \mathrm{~m}$ from the slits?

Accepted Answer

A)  $1 \mathrm{~cm}$ 
B)  $1 \mathrm{~mm}$ 
C)  $0.1 \mathrm{~mm}$ 
D)  $10 \mathrm{~m}$ 
E)  $1 \mu \mathrm{m}$ 
A)  $1 \mathrm{~cm}$ 
B)  $1 \mathrm{~mm}$ 
C)  $0.1 \mathrm{~mm}$ 
D)  $10 \mathrm{~m}$ 
E)  $1 \mu \mathrm{m}$

If you want to design a phototube that ignores all visible light, what should its cathode's work function be?

(For discussion.) On the basis of the information presented, which do you think is the most plausible resolution of the Collapse Rule's problems? Why?

What is -1 expressed as a phase factor?

The ${ }_{8}^{14} \mathrm{O}$ nucleus is unstable. To what will it decay?

Imagine that an electron with an initial spin state $|\psi\rangle=\left[\begin{array}{l}\sqrt{1 / 2} \\\sqrt{1 / 2}\end{array}\right]$ Goes into an SGz device and comes out the - channel of that device. The electron's spin state is now

With an optically perfect 200-power telescope with a 1.5-inch-diameter tube, you can resolve objects roughly how many times closer together than you could with your naked eye? (Choose the closest answer.)

For experiments involving the setup shown in figure Q4.1a, which of the following possible results (if seen) about the value displayed by the ammeter would probably not be consistent with the wave model of light?

Suppose that the tail for a solution to the Schrödinger equation for a given potential energy function is longer in a given classically forbidden region when the energy is $E_{A}$ than that for a solution for energy $E_{B}$ . This means that

Consider wiggle formula $w(t, x)=f(\mathrm{bx}+\mathrm{ct})$ for a transverse wave, where $b$ and $c$ are constants and $f()$ is some arbitrary function. Is this a traveling wave model? If so, in what direction does it travel?

Line waves with wavelength $\lambda$ going through a slit with width a will be diffracted into circular waves with approximately equal amplitude in all forward directions

Which of the state vectors below is not physically equivalent to $|-y\rangle$ ?

Consider a beam of free particles with a certain speed $|\vec{v}|$ . If we double this speed, what happens to the beam's de Broglie wavelength?

A sound wave traveling in air hits the surface of a body of water. Is the reflected wave (A) inverted or (B) upright? (Make a guess.)

One detector built to observe solar neutrinos utilized a huge vat of perchloroethylene $\left(\mathrm{CCl}_{2}\right)$ to absorb neutrinos. If a ${ }_{17}^{37} \mathrm{Cl}$ nucleus absorbs a neutrino, what will it become? (Is the product chemically different from chlorine?)

Imagine that sound waves with a certain definite wavelength flow through a partially open sliding door. If the door is closed somewhat further (but not shut entirely), the angle through which the sound waves are diffracted

The normal mode of a resonating system is sinusoidally disturbed at a frequency $f$ . Assume that $\gamma<<f_{0}$ , where $f_{0}$ is the normal mode's natural frequency. -(b) If $f$ is about $30 f_{0}$ ?

If we shine white light through two slits onto a distant screen, we will see a clear interference pattern.

Conservation Laws Constrain Interactions

The Laws of Physics Are Universal Newtonian Mechanics

The Laws of Physics Are Frame-Independent Relativity

Electricity and Magnetism Are Unified

Some Processes Are Irreversible Thermal Physics

Filters

Exam 5: Matter Behaves Like Waves Quantum Physics

If you want to design a phototube that ignores all visible light, what should its cathode's work function be?

(For discussion.) On the basis of the information presented, which do you think is the most plausible resolution of the Collapse Rule's problems? Why?

What is -1 expressed as a phase factor?

The 814O{ }_{8}^{14} \mathrm{O}814​O nucleus is unstable. To what will it decay?

Imagine that an electron with an initial spin state ∣ψ⟩=[1/21/2]|\psi\rangle=\left[\begin{array}{l}\sqrt{1 / 2} \\\sqrt{1 / 2}\end{array}\right]∣ψ⟩=[1/2​1/2​​] Goes into an SGz device and comes out the - channel of that device. The electron's spin state is now

With an optically perfect 200-power telescope with a 1.5-inch-diameter tube, you can resolve objects roughly how many times closer together than you could with your naked eye? (Choose the closest answer.)

For experiments involving the setup shown in figure Q4.1a, which of the following possible results (if seen) about the value displayed by the ammeter would probably not be consistent with the wave model of light?

Suppose that the tail for a solution to the Schrödinger equation for a given potential energy function is longer in a given classically forbidden region when the energy is EAE_{A}EA​ than that for a solution for energy EBE_{B}EB​ . This means that

Consider wiggle formula w(t,x)=f(bx+ct)w(t, x)=f(\mathrm{bx}+\mathrm{ct})w(t,x)=f(bx+ct) for a transverse wave, where bbb and ccc are constants and f()f()f() is some arbitrary function. Is this a traveling wave model? If so, in what direction does it travel?

Line waves with wavelength λ\lambdaλ going through a slit with width a will be diffracted into circular waves with approximately equal amplitude in all forward directions

Which of the state vectors below is not physically equivalent to ∣−y⟩|-y\rangle∣−y⟩ ?

Consider a beam of free particles with a certain speed ∣v⃗∣|\vec{v}|∣v∣ . If we double this speed, what happens to the beam's de Broglie wavelength?

A sound wave traveling in air hits the surface of a body of water. Is the reflected wave (A) inverted or (B) upright? (Make a guess.)

Imagine that sound waves with a certain definite wavelength flow through a partially open sliding door. If the door is closed somewhat further (but not shut entirely), the angle through which the sound waves are diffracted

The normal mode of a resonating system is sinusoidally disturbed at a frequency fff . Assume that γ<<f0\gamma<<f_{0}γ<<f0​ , where f0f_{0}f0​ is the normal mode's natural frequency. -(b) If fff is about 30f030 f_{0}30f0​ ?

If we shine white light through two slits onto a distant screen, we will see a clear interference pattern.

Conservation Laws Constrain Interactions

The Laws of Physics Are Universal Newtonian Mechanics

The Laws of Physics Are Frame-Independent Relativity

Electricity and Magnetism Are Unified

Some Processes Are Irreversible Thermal Physics

Filters

The ${ }_{8}^{14} \mathrm{O}$ nucleus is unstable. To what will it decay?

Imagine that an electron with an initial spin state $|\psi\rangle=\left[\begin{array}{l}\sqrt{1 / 2} \\\sqrt{1 / 2}\end{array}\right]$ Goes into an SGz device and comes out the - channel of that device. The electron's spin state is now

Suppose that the tail for a solution to the Schrödinger equation for a given potential energy function is longer in a given classically forbidden region when the energy is $E_{A}$ than that for a solution for energy $E_{B}$ . This means that

Consider wiggle formula $w(t, x)=f(\mathrm{bx}+\mathrm{ct})$ for a transverse wave, where $b$ and $c$ are constants and $f()$ is some arbitrary function. Is this a traveling wave model? If so, in what direction does it travel?

Line waves with wavelength $\lambda$ going through a slit with width a will be diffracted into circular waves with approximately equal amplitude in all forward directions

Which of the state vectors below is not physically equivalent to $|-y\rangle$ ?

Consider a beam of free particles with a certain speed $|\vec{v}|$ . If we double this speed, what happens to the beam's de Broglie wavelength?

The normal mode of a resonating system is sinusoidally disturbed at a frequency $f$ . Assume that $\gamma<<f_{0}$ , where $f_{0}$ is the normal mode's natural frequency. -(b) If $f$ is about $30 f_{0}$ ?