Quizbank/Python/conceptual/QB
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QB is the output file, a convenient name since the WV address is of the form [[QB/testname]].
The directory QuizSoftware/conceptual/QB contains two files: One is inserted into the quiz part of the page, and the other goes into the bottom of the talk page. In other words, the talk page to a conceptul quiz acts as a bridge between the WMF Quiz extension and the "magic word" (:t, :?,...) form that permits students two write quizzes and submit them in either wikitext OR textfiles. One reason for doing this is that an explanation :$ can accompany each question. This is a good idea if students are being asked to contribute quiz questions for course credit.
NOTE: Perhaps QuizSoftware/conceptual/conceptual.py needs to be improved so that QB also contains a version that can be pasted as a replacement into v:QB/d_Bell.photon. The problem is that the header contains information that will be tricky to extract and re-insert every time the quiz is upgraded.
temporary[edit | edit source]
QuizSoftware/conceptual/QB/temporary is a useful directory for storing files if a number of conceptual quizzes are being worked on. I don't like to move quizzes in and out of QuizSoftware/bank very often because the the bank contains over a hundred textfiles that need to be kept safe.
d_Bell.photon[edit | edit source]
===*_Quiz_*===
<quiz>
{<!--q1 CCO (public domain) [[user:Guy vandegrift]]-->If the wavelength ''λ'' associated with a photon is cut in half, the photon's energy ''E''}
- is cut in half
- is reduced by a factor of 4
- stays the same
+ becomes twice as big
- becomes 4 times as big
{<!--q2 CCO (public domain) [[user:Guy vandegrift]]-->If the wavelength ''λ'' associated with a photon doubles, the photon's frequency ''f''}
+ is cut in half
- is reduced by a factor of 4
- stays the same
- becomes twice as big
- becomes 4 times as big
{<!--q3 CCO (public domain) [[user:Guy vandegrift]]-->If the frequency ''f'' associated with a photon increases by a factor of 4, the photon's wavelength ''λ''}
- is cut in half
+ is reduced by a factor of 4
- stays the same
- becomes twice as big
- becomes 4 times as big
{<!--q4 CCO (public domain) [[user:Guy vandegrift]]-->If the frequency ''f'' associated with a photon increases by a factor of 4, the photon's energy ''E''}
- is cut in half
- is reduced by a factor of 4
- stays the same
- becomes twice as big
+ becomes 4 times as big
{<!--q5 CCO (public domain) [[user:Guy vandegrift]]-->If an atom emits two photons in a cascade emission and both photons have 2 eV of energy, the atom's energy}
- stays the same
- increases by 2 eV
- increases by 4 eV
- decreases by 2 eV
+ decreases by 4 eV
{<!--q6 CCO (public domain) [[user:Guy vandegrift]]-->If an atom absorbs a photon with 2 eV energy, the atom's energy}
- stays the same
+ increases by 2 eV
- increases by 4 eV
- decreases by 2 eV
- decreases by 4 eV
{<!--q7 CCO (public domain) [[user:Guy vandegrift]]-->If a 3 eV photon strikes a metal plate and causes an electron to escape, that electron will have a kinetic energy that is}
- zero
+ less than 3 eV
- equal to 3 eV
- greater than 3 eV
- equal to 6 eV
{<!--q8 CCO (public domain) [[user:Guy vandegrift]]-->In the [[w:PhET Interactive Simulations|Phet lab]] for photoelectric effect, how was the electron's kinetic energy measured?}
- measuring spin
- measuring polarization
- measuring both spin and polarization
- deflecting the electron with a magnetic field
+ stopping the electron with an applied voltage
{<!--q9 CCO (public domain) [[user:Guy vandegrift]]-->If an atom absorbs a photon with 4 eV energy, the atom's energy}
- stays the same
- increases by 2 eV
- increases by 4 eV
- decreases by 2 eV
+ decreases by 4 eV
{<!--q10 CCO (public domain) [[user:Guy vandegrift]]-->If 10<sup>18</sup> photons pass through a small hole in your roof every second, how many photons would pass through it if you doubled the diameter?}
- 10<sup>18</sup>
- 2x10<sup>18</sup>
+ 4x10<sup>18</sup>
- 6x10<sup>18</sup>
- 8x10<sup>18</sup>
{<!--q11 CCO (public domain) [[user:Guy vandegrift]]-->Two black bodies of are created by cutting identical small holes in two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object has the greater electromagnetic ("photon") energy density (energy per unit volume)?}
+ The hotter object has a greater energy density.
- The larger object has a greater energy density.
- They have the same energy density (since the holes are identical).
- No unique answer exists because two variables are involved (temperature and volume).
{<!--q12 CCO (public domain) [[user:Guy vandegrift]]-->Two black bodies of are created by cutting identical small holes two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object emits more photons per second (above a given threshold energy)?}
+ The object with the greater temperature emits more.
- The object with the greater volume.
- They both emit the same number of photons (since the holes are identical).
- No unique answer exists because two variables are involved (temperature and volume).
{<!--q13 CCO (public domain) [[user:Guy vandegrift]]-->Two black bodies of are created by cutting identical small holes in two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object has the greater electromagnetic ("photon") energy?}
- The hotter object has a greater energy.
- The larger object has a greater energy.
- They have the same energy (since the holes are identical).
+ No unique answer exists because two variables are involved (temperature and volume).
{<!--q14 CCO (public domain) [[user:Guy vandegrift]]-->[[File:Young Diffraction cropped.png|thumb|100px]] This figure is associated with }
- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
+ Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
{<!--q15 CCO (public domain) [[user:Guy vandegrift]]-->[[File:Wave-particle duality static.svg|thumb|100px]] This figure is associated with }
- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
+ Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
{<!--q16 CCO (public domain) [[user:Guy vandegrift]]-->[[File:Photoelectric_effect.svg|thumb|100px]] This figure is associated with }
+ Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
{<!--q17 CCO (public domain) [[user:Guy vandegrift]]-->[[File:Black-body_realization.png|thumb|100px]] This figure is associated with }
- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
+ A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]]
- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
{<!--q18 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 5° when it encounters a filter oriented at 35°. What is the probability that it passes?}
- 0
- 1/4
- 1/2
+ 3/4
- 1
{<!--q19 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 55°. What is the probability that it passes?}
- 0
- 1/4
+ 1/2
- 3/4
- 1
{<!--q20 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 70°. What is the probability that it passes?}
- 0
+ 1/4
- 1/2
- 3/4
- 1
{<!--q21 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 40°. What is the probability that it is blocked?}
- 0
- 1/4
- 1/2
+ 3/4
- 1
{<!--q22 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 5° when it encounters a filter oriented at 50°. What is the probability that it is blocked?}
- 0
- 1/4
+ 1/2
- 3/4
- 1
{<!--q23 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 5° when it encounters a filter oriented at 65°. What is the probability that it is blocked?}
- 0
+ 1/4
- 1/2
- 3/4
- 1
{<!--q24 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 100°. What is the probability that it passes?}
+ 0
- 1/4
- 1/2
- 3/4
- 1
{<!--q25 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 100°. What is the probability that it is blocked?}
- 0
- 1/4
- 1/2
- 3/4
+ 1
</quiz>
d_Bell.photon_talk[edit | edit source]
The talk page version repeats the entire quiz. First in a form designed to be read (and even with permission edited) by students. Then, the RAW TEXT form is given. It is the raw text form that students may submit in either a wiki or as a textfile for class credit. All of this complexity serves only one purpose (which makes me wonder if I really need it): The wikitext version renders very poorly in wikitext, unless it is put into a quiz extension (i.e. using <quiz>{Question}... form). The problem is that not all wikis support quiz extension. If we ever get private wikis that support quiz extension, then it would be great to do away with all this. The private wikis are needed because if students are writing questions for credit in a course, they must do it in private to prevent "espionage" as they compete for grades.
First to allow and display discussion of each
question, and second, to store the quiz in raw-script for.
==[[QB/d_Bell.photon]]==
===1===
*<!--q1 CCO (public domain) [[user:Guy vandegrift]]-->If the wavelength ''λ'' associated with a photon is cut in half, the photon's energy ''E''
- is cut in half
- is reduced by a factor of 4
- stays the same
+ becomes twice as big
- becomes 4 times as big
''c=fλ'' is easy to remember because the dimensions are right. Since ''fλ'' is constant, ''f∝1/λ. ''E=hf'' is harder to remember, but leads to ''E∝f'' leads to ''E∝1/λ'' If wavelength goes down, energy goes up porportionally.
<div style="clear:{{{1|both}}};"></div>
===2===
*<!--q2 CCO (public domain) [[user:Guy vandegrift]]-->If the wavelength ''λ'' associated with a photon doubles, the photon's frequency ''f''
+ is cut in half
- is reduced by a factor of 4
- stays the same
- becomes twice as big
- becomes 4 times as big
''c=fλ'' is easy to remember because the dimensions are right. Since ''fλ'' is constant, ''f∝1/λ. If wavelength doubles, frequency is cut in half.
<div style="clear:{{{1|both}}};"></div>
===3===
*<!--q3 CCO (public domain) [[user:Guy vandegrift]]-->If the frequency ''f'' associated with a photon increases by a factor of 4, the photon's wavelength ''λ''
- is cut in half
+ is reduced by a factor of 4
- stays the same
- becomes twice as big
- becomes 4 times as big
''c=fλ'' is easy to remember because the dimensions are right. Since ''fλ'' is constant, ''f∝1/λ. If wavelength goes up a factor of 4, frequency goes down a factor of 4.
<div style="clear:{{{1|both}}};"></div>
===4===
*<!--q4 CCO (public domain) [[user:Guy vandegrift]]-->If the frequency ''f'' associated with a photon increases by a factor of 4, the photon's energy ''E''
- is cut in half
- is reduced by a factor of 4
- stays the same
- becomes twice as big
+ becomes 4 times as big
Here all we need is the Plank relation between energy and frequency ''E=hf''
<div style="clear:{{{1|both}}};"></div>
===5===
*<!--q5 CCO (public domain) [[user:Guy vandegrift]]-->If an atom emits two photons in a cascade emission and both photons have 2 eV of energy, the atom's energy
- stays the same
- increases by 2 eV
- increases by 4 eV
- decreases by 2 eV
+ decreases by 4 eV
A cascade emission (at two different frequencies) is one way to do a Bell test with photons.
<div style="clear:{{{1|both}}};"></div>
===6===
*<!--q6 CCO (public domain) [[user:Guy vandegrift]]-->If an atom absorbs a photon with 2 eV energy, the atom's energy
- stays the same
+ increases by 2 eV
- increases by 4 eV
- decreases by 2 eV
- decreases by 4 eV
easy question
<div style="clear:{{{1|both}}};"></div>
===7===
*<!--q7 CCO (public domain) [[user:Guy vandegrift]]-->If a 3 eV photon strikes a metal plate and causes an electron to escape, that electron will have a kinetic energy that is
- zero
+ less than 3 eV
- equal to 3 eV
- greater than 3 eV
- equal to 6 eV
First the electron loses KE due to the work function. But also, the stopping voltage measures only the component of KE associated with motion perpendicular to the plate. It is the first consideration that guarantees an energy less than the photon's.
<div style="clear:{{{1|both}}};"></div>
===8===
*<!--q8 CCO (public domain) [[user:Guy vandegrift]]-->In the [[w:PhET Interactive Simulations|Phet lab]] for photoelectric effect, how was the electron's kinetic energy measured?
- measuring spin
- measuring polarization
- measuring both spin and polarization
- deflecting the electron with a magnetic field
+ stopping the electron with an applied voltage
The lab currently can be found at https://phet.colorado.edu/en/simulation/photoelectric
<div style="clear:{{{1|both}}};"></div>
===9===
*<!--q9 CCO (public domain) [[user:Guy vandegrift]]-->If an atom absorbs a photon with 4 eV energy, the atom's energy
- stays the same
- increases by 2 eV
- increases by 4 eV
- decreases by 2 eV
+ decreases by 4 eV
easy question perhaps too easy?
<div style="clear:{{{1|both}}};"></div>
===10===
*<!--q10 CCO (public domain) [[user:Guy vandegrift]]-->If 10<sup>18</sup> photons pass through a small hole in your roof every second, how many photons would pass through it if you doubled the diameter?
- 10<sup>18</sup>
- 2x10<sup>18</sup>
+ 4x10<sup>18</sup>
- 6x10<sup>18</sup>
- 8x10<sup>18</sup>
Area goes as radius squared (basic dimensional analysis says this even if you don't use A=πR<sup>2</sup>
<div style="clear:{{{1|both}}};"></div>
===11===
*<!--q11 CCO (public domain) [[user:Guy vandegrift]]-->Two black bodies of are created by cutting identical small holes in two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object has the greater electromagnetic ("photon") energy density (energy per unit volume)?
+ The hotter object has a greater energy density.
- The larger object has a greater energy density.
- They have the same energy density (since the holes are identical).
- No unique answer exists because two variables are involved (temperature and volume).
This question serves two purposes: (1) to inform students that the "photon" first emerged as a solution to the blackbody problem, and (2) to introduce the distinction between [[w:intensive and extensive properties|intensive and extensive properties]].
<div style="clear:{{{1|both}}};"></div>
===12===
*<!--q12 CCO (public domain) [[user:Guy vandegrift]]-->Two black bodies of are created by cutting identical small holes two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object emits more photons per second (above a given threshold energy)?
+ The object with the greater temperature emits more.
- The object with the greater volume.
- They both emit the same number of photons (since the holes are identical).
- No unique answer exists because two variables are involved (temperature and volume).
We know that the emission spectrum of a black body depends only on temperature (with power also depending on area). [[w:special:permalink/842328570#Carnot's_principle|Carnot's version of the second law of thermodynamics]] stipulates that photon energy must flow from the hotter to the colder object. By inserting filters between the two (identical) holes we can ensure that this equality holds at all wavelengths.
<div style="clear:{{{1|both}}};"></div>
===13===
*<!--q13 CCO (public domain) [[user:Guy vandegrift]]-->Two black bodies of are created by cutting identical small holes in two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object has the greater electromagnetic ("photon") energy?
- The hotter object has a greater energy.
- The larger object has a greater energy.
- They have the same energy (since the holes are identical).
+ No unique answer exists because two variables are involved (temperature and volume).
To suppress blind memorization, this question is a partner to a similar one where the question was about energy ''density''.
<div style="clear:{{{1|both}}};"></div>
===14===
*<!--q14 CCO (public domain) [[user:Guy vandegrift]]-->[[File:Young Diffraction cropped.png|thumb|100px]] This figure is associated with
- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
+ Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
This is the first of four questions that might not suit all instructors. One way to alleviate this is to look at whether a given question is on the test, and talk about that one. Informing students that the others will not be on the test will prevent memorization, but not informing them (and not talking about) will also disincentivize memorization and encourage lecture attendance.
<div style="clear:{{{1|both}}};"></div>
===15===
*<!--q15 CCO (public domain) [[user:Guy vandegrift]]-->[[File:Wave-particle duality static.svg|thumb|100px]] This figure is associated with
- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
+ Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
A candidate for the first "spooky" experiment of quantum mechanics?
<div style="clear:{{{1|both}}};"></div>
===16===
*<!--q16 CCO (public domain) [[user:Guy vandegrift]]-->[[File:Photoelectric_effect.svg|thumb|100px]] This figure is associated with
+ Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
Students will likely memorize only one aspect of this answer. I put the most important first (physical process), and expect other questions on other quizzes to reinforce that it is called the photo-electric effect.
<div style="clear:{{{1|both}}};"></div>
===17===
*<!--q17 CCO (public domain) [[user:Guy vandegrift]]-->[[File:Black-body_realization.png|thumb|100px]] This figure is associated with
- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
+ A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]]
- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
Plank assumed that the walls were perfect conductors, not exactly what is shown.
<div style="clear:{{{1|both}}};"></div>
===18===
*<!--q18 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 5° when it encounters a filter oriented at 35°. What is the probability that it passes?
- 0
- 1/4
- 1/2
+ 3/4
- 1
<math>cos^2 30^\circ=3/4</math>
<div style="clear:{{{1|both}}};"></div>
===19===
*<!--q19 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 55°. What is the probability that it passes?
- 0
- 1/4
+ 1/2
- 3/4
- 1
<math>cos^2 45^\circ=1/2</math>
<div style="clear:{{{1|both}}};"></div>
===20===
*<!--q20 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 70°. What is the probability that it passes?
- 0
+ 1/4
- 1/2
- 3/4
- 1
<math>cos^2 60^\circ=1/4</math>
<div style="clear:{{{1|both}}};"></div>
===21===
*<!--q21 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 40°. What is the probability that it is blocked?
- 0
- 1/4
- 1/2
+ 3/4
- 1
<math>cos^2 30^\circ=1/4</math> so it is blocked with P=3/4
<div style="clear:{{{1|both}}};"></div>
===22===
*<!--q22 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 5° when it encounters a filter oriented at 50°. What is the probability that it is blocked?
- 0
- 1/4
+ 1/2
- 3/4
- 1
<math>1-cos^2 45^\circ=1/2</math>
<div style="clear:{{{1|both}}};"></div>
===23===
*<!--q23 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 5° when it encounters a filter oriented at 65°. What is the probability that it is blocked?
- 0
+ 1/4
- 1/2
- 3/4
- 1
c<math>1-cos^2 30^\circ=1-3/4</math>
<div style="clear:{{{1|both}}};"></div>
===24===
*<!--q24 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 100°. What is the probability that it passes?
+ 0
- 1/4
- 1/2
- 3/4
- 1
obvious
<div style="clear:{{{1|both}}};"></div>
===25===
*<!--q25 CCO (public domain) [[user:Guy vandegrift]]-->A photon is polarized at 10° when it encounters a filter oriented at 100°. What is the probability that it is blocked?
- 0
- 1/4
- 1/2
- 3/4
+ 1
obvious
<div style="clear:{{{1|both}}};"></div>
==Raw script==
==Raw script==
:t QB/d_Bell.photon
:! q1 CCO (public domain) [[user:Guy vandegrift]]
:? If the wavelength ''λ'' associated with a photon is cut in half, the photon's energy ''E''
:- is cut in half
:- is reduced by a factor of 4
:- stays the same
:+ becomes twice as big
:- becomes 4 times as big
:$ ''c=fλ'' is easy to remember because the dimensions are right. Since ''fλ'' is constant, ''f∝1/λ. ''E=hf'' is harder to remember, but leads to ''E∝f'' leads to ''E∝1/λ'' If wavelength goes down, energy goes up porportionally.
:! q2 CCO (public domain) [[user:Guy vandegrift]]
:? If the wavelength ''λ'' associated with a photon doubles, the photon's frequency ''f''
:+ is cut in half
:- is reduced by a factor of 4
:- stays the same
:- becomes twice as big
:- becomes 4 times as big
:$ ''c=fλ'' is easy to remember because the dimensions are right. Since ''fλ'' is constant, ''f∝1/λ. If wavelength doubles, frequency is cut in half.
:! q3 CCO (public domain) [[user:Guy vandegrift]]
:? If the frequency ''f'' associated with a photon increases by a factor of 4, the photon's wavelength ''λ''
:- is cut in half
:+ is reduced by a factor of 4
:- stays the same
:- becomes twice as big
:- becomes 4 times as big
:$ ''c=fλ'' is easy to remember because the dimensions are right. Since ''fλ'' is constant, ''f∝1/λ. If wavelength goes up a factor of 4, frequency goes down a factor of 4.
:! q4 CCO (public domain) [[user:Guy vandegrift]]
:? If the frequency ''f'' associated with a photon increases by a factor of 4, the photon's energy ''E''
:- is cut in half
:- is reduced by a factor of 4
:- stays the same
:- becomes twice as big
:+ becomes 4 times as big
:$ Here all we need is the Plank relation between energy and frequency ''E=hf''
:! q5 CCO (public domain) [[user:Guy vandegrift]]
:? If an atom emits two photons in a cascade emission and both photons have 2 eV of energy, the atom's energy
:- stays the same
:- increases by 2 eV
:- increases by 4 eV
:- decreases by 2 eV
:+ decreases by 4 eV
:$ A cascade emission (at two different frequencies) is one way to do a Bell test with photons.
:! q6 CCO (public domain) [[user:Guy vandegrift]]
:? If an atom absorbs a photon with 2 eV energy, the atom's energy
:- stays the same
:+ increases by 2 eV
:- increases by 4 eV
:- decreases by 2 eV
:- decreases by 4 eV
:$ easy question
:! q7 CCO (public domain) [[user:Guy vandegrift]]
:? If a 3 eV photon strikes a metal plate and causes an electron to escape, that electron will have a kinetic energy that is
:- zero
:+ less than 3 eV
:- equal to 3 eV
:- greater than 3 eV
:- equal to 6 eV
:$ First the electron loses KE due to the work function. But also, the stopping voltage measures only the component of KE associated with motion perpendicular to the plate. It is the first consideration that guarantees an energy less than the photon's.
:! q8 CCO (public domain) [[user:Guy vandegrift]]
:? In the [[w:PhET Interactive Simulations|Phet lab]] for photoelectric effect, how was the electron's kinetic energy measured?
:- measuring spin
:- measuring polarization
:- measuring both spin and polarization
:- deflecting the electron with a magnetic field
:+ stopping the electron with an applied voltage
:$ The lab currently can be found at https://phet.colorado.edu/en/simulation/photoelectric
:! q9 CCO (public domain) [[user:Guy vandegrift]]
:? If an atom absorbs a photon with 4 eV energy, the atom's energy
:- stays the same
:- increases by 2 eV
:- increases by 4 eV
:- decreases by 2 eV
:+ decreases by 4 eV
:$ easy question perhaps too easy?
:! q10 CCO (public domain) [[user:Guy vandegrift]]
:? If 10<sup>18</sup> photons pass through a small hole in your roof every second, how many photons would pass through it if you doubled the diameter?
:- 10<sup>18</sup>
:- 2x10<sup>18</sup>
:+ 4x10<sup>18</sup>
:- 6x10<sup>18</sup>
:- 8x10<sup>18</sup>
:$ Area goes as radius squared (basic dimensional analysis says this even if you don't use A=πR<sup>2</sup>
:! q11 CCO (public domain) [[user:Guy vandegrift]]
:? Two black bodies of are created by cutting identical small holes in two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object has the greater electromagnetic ("photon") energy density (energy per unit volume)?
:+ The hotter object has a greater energy density.
:- The larger object has a greater energy density.
:- They have the same energy density (since the holes are identical).
:- No unique answer exists because two variables are involved (temperature and volume).
:$ This question serves two purposes: (1) to inform students that the "photon" first emerged as a solution to the blackbody problem, and (2) to introduce the distinction between [[w:intensive and extensive properties|intensive and extensive properties]].
:! q12 CCO (public domain) [[user:Guy vandegrift]]
:? Two black bodies of are created by cutting identical small holes two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object emits more photons per second (above a given threshold energy)?
:+ The object with the greater temperature emits more.
:- The object with the greater volume.
:- They both emit the same number of photons (since the holes are identical).
:- No unique answer exists because two variables are involved (temperature and volume).
:$ We know that the emission spectrum of a black body depends only on temperature (with power also depending on area). [[w:special:permalink/842328570#Carnot's_principle|Carnot's version of the second law of thermodynamics]] stipulates that photon energy must flow from the hotter to the colder object. By inserting filters between the two (identical) holes we can ensure that this equality holds at all wavelengths.
:! q13 CCO (public domain) [[user:Guy vandegrift]]
:? Two black bodies of are created by cutting identical small holes in two large containers. The holes are oriented so that all the photons leaving one will enter the other. The objects have different temperature and different volume. Which object has the greater electromagnetic ("photon") energy?
:- The hotter object has a greater energy.
:- The larger object has a greater energy.
:- They have the same energy (since the holes are identical).
:+ No unique answer exists because two variables are involved (temperature and volume).
:$ To suppress blind memorization, this question is a partner to a similar one where the question was about energy ''density''.
:! q14 CCO (public domain) [[user:Guy vandegrift]]
:? [[File:Young Diffraction cropped.png|thumb|100px]] This figure is associated with
:- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
:- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
:- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
:+ Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
:- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
:$ This is the first of four questions that might not suit all instructors. One way to alleviate this is to look at whether a given question is on the test, and talk about that one. Informing students that the others will not be on the test will prevent memorization, but not informing them (and not talking about) will also disincentivize memorization and encourage lecture attendance.
:! q15 CCO (public domain) [[user:Guy vandegrift]]
:? [[File:Wave-particle duality static.svg|thumb|100px]] This figure is associated with
:- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
:+ Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
:- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
:- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
:- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
:$ A candidate for the first "spooky" experiment of quantum mechanics?
:! q16 CCO (public domain) [[user:Guy vandegrift]]
:? [[File:Photoelectric_effect.svg|thumb|100px]] This figure is associated with
:+ Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
:- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
:- A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]] (except that Plank assumed that the walls were conductive.)
:- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
:- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
:$ Students will likely memorize only one aspect of this answer. I put the most important first (physical process), and expect other questions on other quizzes to reinforce that it is called the photo-electric effect.
:! q17 CCO (public domain) [[user:Guy vandegrift]]
:? [[File:Black-body_realization.png|thumb|100px]] This figure is associated with
:- Photons striking metal and ejecting electrons ([[w:Photoelectric effect|photo-electric effect]] explained in 1905)
:- Diffraction observed in light so faint that photons seemed to have no mechanism to interact with each other ([[w:special:permalink/841709261#Career_and_research|observed in 1909]])
:+ A system similar to the one that led to the 1901 proposal that light energy is [[w:Planck's law|quantized as integral multiples of hf]]
:- Evidence presented in 1800 that [[w:Young's interference experiment|light is a wave]].
:- The transfer of energy and momentum of a high energy photon of a [[w:Compton effect|nearly free electron]].
:$ Plank assumed that the walls were perfect conductors, not exactly what is shown.
:! q18 CCO (public domain) [[user:Guy vandegrift]]
:? A photon is polarized at 5° when it encounters a filter oriented at 35°. What is the probability that it passes?
:-0
:-1/4
:-1/2
:+3/4
:-1
:$ <math>cos^2 30^\circ=3/4</math>
:! q19 CCO (public domain) [[user:Guy vandegrift]]
:? A photon is polarized at 10° when it encounters a filter oriented at 55°. What is the probability that it passes?
:-0
:-1/4
:+1/2
:-3/4
:-1
:$ <math>cos^2 45^\circ=1/2</math>
:! q20 CCO (public domain) [[user:Guy vandegrift]]
:? A photon is polarized at 10° when it encounters a filter oriented at 70°. What is the probability that it passes?
:-0
:+1/4
:-1/2
:-3/4
:-1
:$ <math>cos^2 60^\circ=1/4</math>
:! q21 CCO (public domain) [[user:Guy vandegrift]]
:? A photon is polarized at 10° when it encounters a filter oriented at 40°. What is the probability that it is blocked?
:-0
:-1/4
:-1/2
:+3/4
:-1
:$ <math>cos^2 30^\circ=1/4</math> so it is blocked with P=3/4
:! q22 CCO (public domain) [[user:Guy vandegrift]]
:? A photon is polarized at 5° when it encounters a filter oriented at 50°. What is the probability that it is blocked?
:-0
:-1/4
:+1/2
:-3/4
:-1
:$ <math>1-cos^2 45^\circ=1/2</math>
:! q23 CCO (public domain) [[user:Guy vandegrift]]
:? A photon is polarized at 5° when it encounters a filter oriented at 65°. What is the probability that it is blocked?
:-0
:+1/4
:-1/2
:-3/4
:-1
:$ c<math>1-cos^2 30^\circ=1-3/4</math>
:! q24 CCO (public domain) [[user:Guy vandegrift]]
:? A photon is polarized at 10° when it encounters a filter oriented at 100°. What is the probability that it passes?
:+0
:-1/4
:-1/2
:-3/4
:-1
:$ obvious
:! q25 CCO (public domain) [[user:Guy vandegrift]]
:? A photon is polarized at 10° when it encounters a filter oriented at 100°. What is the probability that it is blocked?
:-0
:-1/4
:- 1/2
:- 3/4
:+ 1
:$ obvious
:z