20120229

Physics quiz question: real image with greatest magnification

Physics 205B Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

Placing an object __________ to the left of a converging lens would produce a real image with the greatest magnification.
(A) out at ∞.
(B) just outside the focal length.
(C) just inside the focal length.
(D) almost next to the lens.

Correct answer: (B)

In order to produce a real image from a converging lens, an object should be placed at a distance anywhere from +f < p < +∞. As linear magnification m = -q/p = f/(f - p), the greatest magnified real image will result in the limit where p -> f.

Response (C) would result in a virtual image with the greatest magnification.

Section 30882
Exam code: quiz02gL4s
(A) : 1 student
(B) : 18 students
(C) : 5 students
(D) : 0 students

Success level: 75%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.47

20120228

Physics quiz question: object to produce real image by converging lens

Physics 205B Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 23.57

An image is located +7.0 cm (to the right) of a converging lens with a focal length of +5.5 cm. The object distance (to the left of the converging lens) is:
(A) +3.1 cm.
(B) +3.9 cm.
(C) +8.0 cm.
(D) +26 cm.

Correct answer (highlight to unhide): (D)

With the image distance q = +7.0 cm, and focal length f = +5.5 cm in the thin lens equation, the object distance p is:

(1/p) = (1/f) - (1/q),

such that:

p = +25.667 cm, or to two significant figures, +27 cm.

Response (A) is (1/p) = (1/f) + (1/q); response (B) is (1/p); response (C) is 100/(f + q).

Section 30882
Exam code: quiz02gL4s
(A) : 1 student
(B) : 3 students
(C) : 0 students
(D) : 20 students

Success level: 83%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

20120227

Astronomy current events question: dwarf galaxy NGC 4449

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Charles Q. Choi, "Twisted Dwarf Galaxy Warped by Cosmic 'Stealth Merger'," February 8, 2012
http://www.msnbc.msn.com/id/46314513/ns/technology_and_science-space/#.T0w34XLLw0U
The distorted shape and furious star formation rate of dwarf galaxy NGC 4449 may be due to a newly discovered __________ nearby.
(A) dark matter cloud.
(B) supermassive black hole.
(C) dark energy stream.
(D) type II supernova.
(E) smaller dwarf galaxy.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 3 students
(B) : 9 students
(C) : 1 student
(D) : 6 students
(E) : 31 students

Astronomy current events question: Venus spin rate

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
ESA press release, "Could Venus Be Shifting Gear?," February 10, 2012
http://www.esa.int/esaSC/SEM0TLSXXXG_index_0.html
Venus may spin slower than previously measured, according to __________ recorded by the European Space Agency Venus Express spacecraft.
(A) infrared images of surface feature positions.
(B) GPS discrepancies with Earth's position.
(C) gravity wave oscillations.
(D) underground magma currents.
(E) magnetic pole strengths.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 23 students
(B) : 9 students
(C) : 6 students
(D) : 2 students
(E) : 6 students

Astronomy current events question: Sagittarius A* x-ray flares

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Trent J. Perrotto, Megan Watzke, and Janet Anderson, "NASA's Chandra Finds Milky Way's Black Hole Grazing on Asteroids," February 8, 2012
http://www.nasa.gov/mission_pages/chandra/news/H-12-049.html
According to UK researchers, daily x-ray flares detected by NASA's Chandra X-ray Observatory may be due to __________ the supermassive black hole Sagittarius A* at the center of the Milky Way.
(A) asteroids vaporized and devoured by.
(B) supernovae triggered by.
(C) matter and antimatter ejected from.
(D) a wormhole connected to.
(E) superheated plasma surrounding.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 38 students
(B) : 3 students
(C) : 6 students
(D) : 0 students
(E) : 4 students

Physics quiz archive: lenses, optical instruments

Physics 205B Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

Section 30882, version 1
Exam code: quiz02gL4s
Section 30882 results
Quiz 2 results (max score = 30):
0- 6 : ** [low = 6]
7-12 : *****
13-18 : ****
19-24 : ********* [mean = 18.6 +/- 7.7]
25-30 : **** [high = 30]

20120226

Astronomy quiz question: Large Binocular Telescope interferometry

Astronomy 210 Quiz 3, spring semester 2012
Cuesta College, San Luis Obispo, CA

Consider the Large Binocular Telescope located at Mt. Graham, AZ. The mirrors of these two optical telescopes are separated from each other to improve:
(A) light-gathering power.
(B) resolving power.
(C) magnifying power.
(D) (Two of the above choices.)
(E) (All of the above choices.)
(F) (None of the above choices.)

(Image credit: Large Binocular Telescope/NASA, http://www.nasa.gov/topics/universe/features/lbti20101206-i.html.)

Correct answer: (B)

Increasing the distance between connected telescopes creates a much larger effective diameter to increase resolving power.

Section 30674
Exam code: quiz03n0T7
(A) : 5 students
(B) : 23 students
(C) : 2 students
(D) : 3 students
(E) : 0 students
(F) : 0 students

Success level: 73% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.89

Section 30676
Exam code: quiz03SL3w
(A) : 12 students
(B) : 18 students
(C) : 2 students
(D) : 4 students
(E) : 2 students
(F) : 2 students

Success level: 50% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.60

20120225

Astronomy quiz question: reflector versus refractor costs

Astronomy 210 Quiz 3, spring semester 2012
Cuesta College, San Luis Obispo, CA

Large optical telescopes are reflectors rather than refractors because mirrors:
(A) are much easier to clean than lenses.
(B) are unaffected by light pollution, compared to lenses.
(C) can be used with different eyepieces, unlike lenses.
(D) can be made of lower quality materials than those used for lenses.

Correct answer: (D)

Since light must pass through a lens, the material must be internally flawless, in contrast to a reflector, where only the surface needs to be flawless.

Section 30676
Exam code: quiz03SL3w
(A) : 2 students
(B) : 14 students
(C) : 7 students
(D) : 16 students

Success level: 43% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.60

20120224

Astronomy quiz question: charge-coupled devices

Astronomy 210 Quiz 3, spring semester 2012
Cuesta College, San Luis Obispo, CA

Charge-coupled devices (CCDs) are more useful than photographic plates for optical telescopes because CCDs:
(A) can measure brightnesses more precisely.
(B) are cheap and disposable.
(C) do not produce diffraction fringes.
(D) are not susceptible to chromatic aberration.

Correct answer: (A)

Response (C) is a limitation on the resolving power of a telescope, which ultimately depends on the diameter of its primary mirror (or lens), and not on the media used to record images. Response (D) is a property of optical telescope lenses (but not of optical telescope mirrors).

Section 30674
Exam code: quiz03n0T7
(A) : 17 students
(B) : 1 student
(C) : 11 students
(D) : 4 students

Success level: 56% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.26

20120222

Astronomy quiz question: total solar eclipse location

Astronomy 210 Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

An observer in San Luis Obispo, CA is watching a total solar eclipse. During this eclipse, the observer is located in:
(A) the moon's umbra.
(B) the moon's penumbra.
(C) the moon's negative shadow.
(D) Earth's umbra.
(E) Earth's penumbra.

Correct answer (highlight to unhide): (A)

For a total solar eclipse, the new moon is between the sun and Earth, blocking light the light from the sun. All observers in the umbra (the "complete" shadow zone) of the moon would have all sunlight blocked from reaching them, and thus they would see a total solar eclipse.

(Response (B) would be for a partial solar eclipse (assuming that is the maximum extent of its progress), response (C) would be for an annular solar eclipse. Responses (D) and (E) correspond to the location of the moon during a total and partial lunar eclipse, respectively.)

Section 30676
Exam code: quiz02SnT4
(A) : 20 students
(B) : 4 students
(C) : 7 students
(D) : 9 students
(E) : 1 student
(No response : 1 student)

Success level: 52% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.57

20120221

Astronomy quiz question: parallax of Tycho's supernova

Astronomy 210 Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

Tycho disproved that the heavens were perfect and unchanging by:
(A) explaining how the moon creates ocean tides.
(B) seeing no parallax for a new star.
(C) observing the motion of Jupiter's satellites.
(D) losing his nose in a duel defending the principles of science.

Correct answer: (B)

Tycho could not discern any parallax for a supernova in 1572, and thus concluded that it was distant enough to be part of the supposedly perfect, unchanging celestial sphere of stars.

Section 30676
Exam code: quiz02SnT4
(A) : 12 students
(B) : 20 students
(C) : 10 students
(D) : 0 students

Success level: 51% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.73

20120220

Astronomy quiz question: transit of Venus

Astronomy 210 Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

In a rare event, the planet Venus will be observed in June 2012 as a tiny dark dot in the middle of the disk of the sun, for observers in San Luis Obispo, CA, who are located in:
(A) Venus' umbra.
(B) Venus' penumbra.
(C) Venus' negative shadow.
(D) Earth's umbra.
(E) Earth's penumbra.

Correct answer: (C)

During an annular solar eclipse, the angular size of the moon is (slightly) too small to completely cover the sun, as seen by an observer in the negative shadow zone (the antumbra) of the moon. This is similar to a transit of Venus, where its comparatively tiny angular size makes it appear to be a dot as it moves across the disk of the sun. Again as in an annular solar eclipse, the observer is in the negative shadow zone of Venus.

Section 30674
Exam code: quiz02n0Is
(A) : 14 students
(B) : 6 students
(C) : 7 students
(D) : 4 students
(E) : 3 students

Success level: 27% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.27

20120219

Found astronomy: astrology, or astronomy?

14327646.jpg
http://memegenerator.net/instance/14327646

"Futurama Fry Not Sure If..." meme to be shown on the first day of class...

Astronomy quiz question: Galileo's observation of the moons of Jupiter

Astronomy 210 Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

Galileo's observations of the moons of Jupiter supported the heliocentric model of planetary motion over the geocentric model because:
(A) their orbits were elliptical instead of circular.
(B) it showed that epicycles and deferents were not real.
(C) no parallax was observed.
(D) there could be centers of motion other than Earth.

Correct answer: (D)

Although the observations of Jupiter being orbited by its moons did not prove the heliocentric model of planetary motion, it did make it plausible that Earth could orbit the sun, and not leave the moon behind.

Section 30674
Exam code: quiz02n0Is
(A) : 4 students
(B) : 0 students
(C) : 1 student
(D) : 27 students
(No response : 1 student)

Success level: 80% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.56

20120218

Online reading assignment question: Galileo's observation of Jupiter's moons

Astronomy 210, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, reviewing material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

(The following question was asked previous to the lecture covering Galileo's telescopic observations.)

(Graded for completion.) Galileo used the observations of Jupiter's moons to explain...

The following are all of the student responses to this question, verbatim and unedited.
"the movement of them."

"He used Jupiter's moons to explain that the earth was not the center of the universe."

"Galileo used the observations of Jupiter's moon to explain that Earth could move and not leave its moons behind. Galileo proved that Jupiter's moon revolved around Jupiter, so there could be center of motion other than earth."

"that earth is not the center of the solar system, but the sun is."

"How the moon can revolve around the earth because Jupiter is able to keep its moons. There can be centers of motion other than the earth."

"that there were at least two centers of motion"

"with the abservations of the moons of jupiter, it showed the importance of the telescope as a tool for astronomers."

"Observations on subsequent nights showed that the positions of these 'stars' relative to Jupiter were changing in a way that would have been inexplicable if they had really been fixed stars."

"that the moons revolved around Jupiter and this proved that there were other centers of motion other than Earth's."

"Galileo used the moons of Jupiter to explain how there were centers of motion in the universe other than Earth."

"The solar system could be sun centered and not earth centered."

"Earths moon revolves around our planet and not the other way around. Earths is the center of our gravity."

"that if jupiter moved and kept it's moons, then the earth could move and keep it's moons. If jupiter's moons revolve around jupiter, then there are centers of motion besides the earth."

"Galileo suggest that Jupiter can move and keep its moon and so earth could do the same thing"

"In 1610 Galileo used his 'new' telescope to see Jupiter's 4 different satellites."

"That the Earth did move kept its moon, because Jupiter moved and kept its satellites."

"That we are not the center of the universe. We actually orbit the sun instead of everything orbiting the earth."

"That since Jupiter moved without leaving its moons behind, so could Earth."

"Galileo used the observations to determine that the earth could move and keep its moon. He showed that Jupiter's moons revolve around Jupiter so there could be centers of motion other than earth."

"Galileo also noticed that Jupiter's innermost moon had the shortest orbital period and the moons further from Jupiter had proportionally longer periods. So the earth therefore could revolve around the sun."

"how earth wasn't the center of motion and how everything was circling the sun."

"That the earth can move without losing the moon. And that there could be a larger mass for earth to revolve around."

"The revolving situation of the planets and moons"

"The ptolemaic model"

"That because Jupiter kept its satellites when it moved, that Earth could too move and keep its motion. He showed how Jupiter's moons revolved around Jupiter therefor there could be centers of motion other than Earth. Galileo saw all of his as indication that the sun was the center of our solar system and not the Earth."

"that Earth's moon revolves around the Earth and not the other way around. Earth is the center of gravity."

"which way Jupiter moved, and found that the stars moved with it."

"Galileo used Jupiter's moons to prove that the planets didn't revolve around the Earth."

"Earth too could move and keep its moon. And that the solar system can be sun centered and not earth centered."

"That there could be centers of motion other than Earth."

"how the earth could orbit the sun while still keeping the moon in its orbit."

"that the earth moved"

"That we revolve around the sun."

"He saw that the universe was sun centered, but Earth centered."

"that everything revolved the earth."

"that there could be centers of motion other than Earth."

"That the solar system could be sun-centered, not Earth centered, also that the Earth could move and keep its moon with it."

"how things must revolve around the earth?"

"The phases of the moon."

"the heliocentric model of astronomy."

"that Earth could still keep its moon while moving."

"How the planets revolved around the sun and the moons around the planets, thus disproving the traditional Aristotelian cosmology that said everything revolved around the sun."

"Galileo used the observations of Jupiter's moons to explain that Earth can move around the sun without 'losing' its moon, or leaving it behind in its orbit around the sun.
when jupiter is closests to the sun."

"earth did not move."

"to discover celestial bodies"

"sun as center of universe"

"the movement of our moon"

"the orbiting of objects around planets."

"Galileo used the observations of Jupiter's moon to explain that earth also moved and had the ability to keep it's moons. He also showed that there other centers of motion other than earth."

"the Copernican model that Earth could move and keep its moon."

"the revolution of the earth."

"That there could be other centers of motion besides Earth which helped the idea that the solar system could be centered around the sun instead of the Earth. It supported evidence against Ptolemy's model."

"the movement of the satelites around Jupiter"

"the passing of the months"

"How the moon revolved around earth, or earth revolved around the sun."

"how there are centers of motion other than earth. Jupiter's moons revolve around jupiter and thus"

"our moon revolves around earth and everything is sun centered not earth centered."

"that there are things in space that are not visible by the naked eye, thus showing the world the importance of the telescope."

"Jupiter's moons explained that even though Jupiter was moving in orbit, it still kept it's moons."

"This proved that Earth also could move and keep it's moons, helping Galileo prove that the heliocentric model could be true."

"Galileo used the oberservations of Jupiter's moons to explain that the earth, too, could move and keep the moon and it wont get left behind as they thought."

"that the solar system could be sun centered and not Earth centered."

"to provide evidence against the Ptolemaic model."

"why the Ptolemaic model was wrong."

"that not all motion was centered on the Earth and that there could be other centers of motion."

"Saw it as an implication that the solar system could be sun centered and not Earth centered."

"That the Earth can move without leaving the moon behind because Jupiter kept its satellite's, thus disproving Aristotle's philosophy that all heavenly motion was centered on Earth; Galileo saw indication that the sun was the center of the solar system and not the Earth."

"lunar orbits"

"To study saturn, and to observe the phases of venus."

"rotation"

"Galileo showed that Jupiter's moons resolve around Jupiter, so there could be centers of motion other than the Earth."

"That the telescope was proof that some objects can't be seen by the bare eye, along with his geocentric theory that everything orbits around earth."

"That there can be other center points of revolution other than earth."

Astronomy quiz archive: eclipses/history of astronomy

Astronomy 210 Quiz 2, spring semester 2012
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz02n0Is
Section 30674
0- 8.0 : *** [low = 6.5]
8.5-16.0 : *******
16.5-24.0 : ************ [mean = 20.5 +/- 7.1]
24.5-32.0 : **********
32.5-40.0 : ** [high = 33.0]


Section 30676, version 1
Exam code: quiz02SnT4
Section 30676
0- 8.0 : **** [low = 3.5]
8.5-16.0 : *******
16.5-24.0 : ***************** [mean = 21.0 +/- 8.6]
24.5-32.0 : *************
32.5-40.0 : ****** [high = 40.0]

20120217

Astronomy current events question: IBEX and interstellar atoms

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Ray Villard and Jane Rigby, "IBEX: Glimpses of the Interstellar Material Beyond our Solar System," January 31, 2012
http://www.nasa.gov/mission_pages/ibex/news/interstellar-difference.html
NASA's Interstellar Boundary Explorer discovered atoms that originated outside our solar system by comparing:
(A) galactic wind directions.
(B) trace amounts of iridium.
(C) cosmic ray intensities.
(D) differences in radioactive decays.
(E) oxygen and neon atom ratios.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 5 students
(B) : 3 students
(C) : 2 students
(D) : 4 students
(E) : 16 students

20120216

Astronomy current events question: galaxy RCS2 032727-132623 magnification

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Ray Villard and Jane Rigby, "Hubble Zooms in on a Magnified Galaxy," February 2, 2012
http://www.nasa.gov/mission_pages/hubble/science/magnified-galaxy.html
The extremely distant galaxy RCS2 032727-132623 appears magnified when viewed by NASA's Hubble Space Telescope because of:
(A) magnetic interference from solar flares.
(B) gravitational lensing from a nearby galaxy.
(C) extreme blueshifted light.
(D) a recent software upgrade.
(E) a new lens attachment.

Correct answer: (B)

Student responses
Sections 30678, 30679, 30680
(A) : 8 students
(B) : 8 students
(C) : 3 students
(D) : 1 student
(E) : 6 students

Astronomy current events question: habitable-zone planet GJ 667Cc

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Irene Klotz, "New Alien Planet Ripe for Life?," February 2, 2012
http://news.discovery.com/space/exoplanet-gj667cc-120202.html
Researchers discovered GJ 667Cc, a planet where liquid water may exist, by analyzing:
(A) water vapor trails.
(B) its overall density.
(C) tidal patterns.
(D) light reflected by oceans.
(E) wobbles in the star it orbits.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 10 students
(B) : 6 students
(C) : 6 students
(D) : 8 students
(E) : 26 students

20120215

Overheard: difference between incoherent and coherent light

Physics 205B, spring semester 2012
Cuesta College, San Luis Obispo, CA

(Overheard during a recap of the results of an online reading assignment, at the start of a lecture on wave optics.)

Instructor: "The difference between an incoherent light source and a coherent light source is...?"

Student: (Beat.) "...The 'in?'"

Astronomy current events question: MoonKAM camera

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Dwayne Brown, Caroline McCall, and Whitney Lawrence Mullen, "NASA Mission Returns First Video From Moon's Far Side," February 1, 2012
http://www.nasa.gov/mission_pages/grail/news/grail20120201.html
The MoonKAM camera aboard NASA's twin Gravity Recovery And Interior Laboratory spacecraft is designed for __________ on the moon's surface.
(A) evaluating new landing sites.
(B) recording live footage of impact events.
(C) middle school students to select areas to study.
(D) measuring frozen water.
(E) detecting effects of solar flares.

Correct answer: (C)

Student responses
Sections 30678, 30679, 30680
(A) : 8 students
(B) : 16 students
(C) : 29 students
(D) : 4 students
(E) : 3 students

20120214

Physics quiz question: time for light to travel a centimeter

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

How long does it take light to travel 1 inch (2.54 cm) in vacuum?
(A) 8.47×10–11 s.
(B) 1.18×10–10 s.
(C) 1.31×10–7 s.
(D) 7.62×10–6 s.

Correct answer: (C)

The speed of light in vacuum is c = 3.00×108 m/s, and the relation between speed, distance, and elapsed time is:

c = ∆x/∆t,

such that solving for time gives:

t = (∆x)/c = (3.00×108 m/s)/(1×10-2 m) = 8.47×10–11 s.

Response (B) is c/∆x (with a sign error in the exponent); response (C) is 1/(c*∆x); and response (D) is c*∆x (with a sign error in the exponent).

Section 30882
Exam code: quiz01pL2r
(A) : 17 students
(B) : 10 students
(C) : 1 student
(D) : 1 student

Success level: 59%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.83

20120213

Physics quiz question: frequency of light, in different media

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 22.19(b)

Red laser light of wavelength 633 nm in air passes either into man-made fused quartz (index of refraction 1.459), or into natural crystalline quartz (index of refraction 1.544). In which material would the red laser light have the higher frequency?
(A) Fused quartz.
(B) Crystalline quartz.
(C) (There is a tie.)
(D) (Not enough information given.)

Correct answer: (C)

Frequency f depends on the properties of the source, and is independent of the properties of the medium (i.e., different speeds due to different indices of refraction).

Section 30882
Exam code: quiz01pL2r
(A) : 4 students
(B) : 3 students
(C) : 21 students
(D) : 0 students

Success level: 72%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.50

20120211

Physics quiz question: polarization by scattering

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Question 22.6

If the sun is directly overhead, and you are looking at the east horizon, you would observe light that is:
(A) partially polarized horizontally, north-south.
(B) partially polarized horizontally, east-west.
(C) partially polarized vertically (up-down).
(D) randomly polarized (unpolarized).

Correct answer: (A)

Unpolarized light from overhead sun, intercepted by particle along the east horizon, makes particle vibrate north-south and east-west. From your viewpoint, you would only see the north-south polarization mode, as the east-west mode would be longitudinal (which light waves are not).

Section 30882
Exam code: quiz01pL2r
(A) : 26 students
(B) : 2 students
(C) : 0 students
(D) : 1 student

Success level: 90%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33

20120210

Physics quiz question: reception from electric dipole antenna

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Multiple-Choice Question 22.1

"KJ4AED And His Portable 40m Antenna"
Greg Cohoon
flic.kr/p/6PMS1H

A radio station is located due south of your location. It uses an electric dipole antenna oriented horizontally north-south. In order to maximize reception of this broadcast at your location, you need to orient an electric dipole receiving antenna:
(A) vertically.
(B) horizontally north-south.
(C) horizontally east-west.
(D) (No reception is possible using an electric dipole antenna.)

Correct answer (highlight to unhide): (D)

An electric dipole antenna will broadcast most effectively in all directions perpendicular to its orientation, which for this horizontal north-south antenna would be to the east and to the west of its location (as well as directly overhead, or anywhere in the sky along an east-to-west line). There would be zero signal broadcast to the north and to the south of the antenna, as those locations would be looking at the antenna end-on, and there would be no detectable transverse oscillations.

Section 30882
Exam code: quiz01pL2r
(A) : 2 students
(B) : 2 students
(C) : 4 students
(D) : 21 students

Success level: 72%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.83

20120209

Physics quiz question: incident angle less than critical angle

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 23.11

A beam of light strikes the interface between flint glass and air with an incident angle equal to the critical angle of 35.9°, such that the beam undergoes total internal reflection. (Drawing is not to scale.) If the incident angle of the beam of light in flint glass is decreased slightly from 35.9° to 35.8°, the incident beam would be:
(A) reflected back into flint glass.
(B) transmitted into air.
(C) (Both choices (A) and (B).)
(D) (Not enough information is given.)

Correct answer: (C)

If the incident angle in flint glass is less than the critical angle, then light will be transmitted out into the air, as well as partially reflected back into the flint glass.

Section 30882
Exam code: quiz01pL2r
(A) : 9 students
(B) : 3 students
(C) : 17 students
(D) : 0 students

Success level: 59%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

20120208

Physics quiz archive: electromagnetic waves, reflection/refraction

Physics 205B Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

Section 30882, version 1
Exam code: quiz01pL2r
Section 30882 results
Quiz 1 results (max score = 30):
0- 6 :
7-12 : ** [low = 9]
13-18 : **********
19-24 : ***** [mean = 22.4 +/- 6.5]
25-30 : ************ [high = 30]

20120207

Astronomy current events question: Fobos-Grunt mission objective

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Jonathan Amos, "Phobos-Grunt: Failed Probe 'Falls Over Pacific,'" January 15, 2012
http://www.bbc.co.uk/news/science-environment-16491457
The Russian Space Agency Fobos-Grunt ("Phobos-Ground") spacecraft, which crash-landed into the Pacific, was intended to travel to Mars to:
(A) bring back a sample from one of its moons.
(B) burrow underground to search for water.
(C) produce fuel for future space missions.
(D) search for the defunct NASA Spirit rover.
(E) map the "face on Mars" with high-resolution radar.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 31 students
(B) : 8 students
(C) : 1 student
(D) : 2 students
(E) : 14 students

Astronomy current events question: Opportunity rover charging batteries

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Kelly Beatty, "Opportunity Takes a Bow, Gets Some Rest," January 25, 2012
http://www.skyandtelescope.com/news/home/Opportunity-Takes-Bow-Gets-Rest-138098593.html
The NASA Mars Exploration Rover Opportunity will park for the next several months, to:
(A) charge batteries during Martian winter.
(B) listen for Mars microquakes.
(C) upgrade and reboot its operating software.
(D) wait for the quicksand around it to harden.
(E) avoid exposure to solar flares.

Correct answer: (A)

Student responses
Sections 30678, 30679, 30680
(A) : 18 students
(B) : 6 students
(C) : 1 student
(D) : 0 students
(E) : 2 students

Astronomy current events question: subsurface ice on Vesta?

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Elizabeth Zubritsky and Jia-Rui Cook, "Vesta Likely Cold and Dark Enough for Ice," January 25, 2012
http://www.nasa.gov/mission_pages/dawn/news/dawn20120125.html
The asteroid Vesta may contain ice just below its surface, according to models based on:
(A) Antarctic glaciers.
(B) a Russian space probe drilling into its crust.
(C) meteorite samples containing Vesta material.
(D) Hubble Space Telescope observations.
(E) icy vapor trails.

Correct answer: (D)

Student responses
Sections 30678, 30679, 30680
(A) : 4 students
(B) : 2 students
(C) : 7 students
(D) : 15 students
(E) : 0 students

Astronomy current events question: "Meteorito" wine

Astronomy 210L, spring semester 2012
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Lauren Davis, "Hate Earthy Wines? Try One Made from Meteorites," January 21, 2012
http://io9.com/5878095/hate-earthy-wines-try-one-made-from-meteorites
"Meteorito" is a new Chilean wine for sale:
(A) made from grapes grown in the soil of an ancient impact crater.
(B) infused with a meteorite fragment.
(C) approved by International Space Station astronauts.
(D) from the La Silla Paranal Observatory vineyard.
(E) based on a popular Chilean science-fiction movie.

Correct answer: (E)

Student responses
Sections 30678, 30679, 30680
(A) : 10 students
(B) : 36 students
(C) : 2 students
(D) : 8 students
(E) : 0 students

20120206

Astronomy quiz question: Ursa Major/Cassiopeia position

Astronomy 210 Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
Consider the view of the northern horizon shown below, as seen by an observer on February 2 in San Luis Obispo, CA. Ignore daylight saving time. Assume you can see stars in daylight. What time is this?
(A) 5:00 AM.
(B) 10:00 AM.
(C) 12:00 PM.
(D) 9:00 PM.

Correct answer: (B)

Response (A) has Cassiopeia at its lowest point in the sky on February 2; response (C) corresponds to the sky on January 1; and response (D) has Cassiopeia to the left (west) of Polaris on February 2.

Section 30676
Exam code: quiz01sH0p
(A) : 1 student
(B) : 39 students
(C) : 2 students
(D) : 6 students

Success level: 83% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.46


[Version 2]
Consider the view of the northern horizon shown below, as seen by an observer on February 2 in San Luis Obispo, CA. Ignore daylight saving time. Assume you can see stars in daylight. What time is this?
(A) 10:00 AM.
(B) 12:00 PM.
(C) 2:00 PM.
(D) 9:00 PM.

Correct answer: (A)

Response (B) corresponds to the sky on January 1; response (C) has Ursa Major at its lowest point in the sky on February 2; and response (D) has Ursa Major to the right (east) of Polaris on February 2.

Section 30674
Exam code: quiz01n3Wb
(A) : 27 students
(B) : 1 student
(C) : 0 students
(D) : 4 students
(No response : 1 student)

Success level: 79% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22

20120205

Astronomy quiz question: time to change moon phases

Astronomy 210 Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
Approximately how much time elapses between first quarter to full moon?
(A) An hour.
(B) Several hours.
(C) 12 hours.
(D) 24 hours.
(E) Several days.
(F) One week.
(G) Several weeks.
(H) 28 days.

Correct answer: (F)

The moon will take approximately four weeks to go through all eight of its phases, such that it will take approximately one week to go through two phases (starting from first quarter, to go through waxing gibbous, to end at full moon).

Section 30674
Exam code: quiz01n3Wb
(A) : 0 students
(B) : 1 student
(C) : 0 students
(D) : 0 students
(E) : 2 students
(F) : 26 students
(G) : 4 students
(H) : 1 student
(No response : 1 student)

Success level: 77% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

[Version 2]
Approximately how much time elapses between full moon to third quarter?
(A) An hour.
(B) Several hours.
(C) 12 hours.
(D) 24 hours.
(E) Several days.
(F) One week.
(G) Several weeks.
(H) 28 days.

Correct answer: (F)

Section 30676
Exam code: quiz01sH0p
(A) : 0 students
(B) : 0 students
(C) : 0 students
(D) : 0 students
(E) : 3 students
(F) : 35 students
(G) : 8 students
(H): 2 students

Success level: 75% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.62

20120204

Astronomy quiz question: moon phase, overhead to setting?

Astronomy 210 Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

[Version 1]
The waxing gibbous moon is directly overhead at 9:00 PM. What phase will the moon have when it sets? Clearly circle your answer below.

Correct answer: (A) (Waxing gibbous.)

Section 30676
Exam code: quiz01sH0p
(A) : 26 students
(B) : 3 students
(C) : 6 students
(D) : 0 students
(E) : 3 students
(F) : 1 student
(G) : 6 students
(H): 0 students
(No response : 3 students

Success level: 57% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.48

[Version 2]
The waning gibbous moon is directly overhead at 3:00 AM. What phase will the moon have when it sets? Clearly circle your answer below.

Correct answer: (G) (Waning gibbous.)

The moon will take approximately four weeks to go through all eight of its phases, such that it will take approximately one week to go through two phases, or approximately half of a week to go to the next consecutive phase. As the moon takes approximately 12 hours from moonrise to moonset, the phase it has while overhead will be the same phase as it sets six hours later.

Section 30674
Exam code: quiz01n3Wb
(A) : 2 students
(B) : 0 students
(C) : 4 students
(D) : 1 student
(E) : 12 students
(F) : 1 student
(G) : 15 students
(H) : 0 students

Success level: 46% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.56

20120203

Astronomy quiz archive: stars/sun/seasons/moon phases

Astronomy 210 Quiz 1, fall semester 2012
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz01n3Wb
Section 30674
0- 8.0 : ** [low = 7.0]
8.5-16.0 : ***
16.5-24.0 : ************
24.5-32.0 : *********** [mean = 24.7 +/- 7.9]
32.5-40.0 : ******* [high = 40.0]


Section 30676, version 1
Exam code: quiz01sH0p

Section 30676
0- 8.0 : ** [low = 7.5]
8.5-16.0 : *******
16.5-24.0 : ***********
24.5-32.0 : **************** [mean = 25.4 +/- 9.0]
32.5-40.0 : ************ [high = 40.0]

20120202

Astronomy quiz question: sun-zodiac timing

Astronomy 210 Quiz 1, spring semester 2012
Cuesta College, San Luis Obispo, CA

If the sun is in front of a certain zodiac constellation today, it will take approximately __________ to be in front of the next zodiac constellation.
(A) an hour.
(B) 12 hours.
(C) 24 hours.
(D) one month.
(E) one year.
(F) 26,000 years.

Correct answer: (D).

With one year for Earth to complete one revolution around the sun, and 12 zodiac constellations approximately evenly spaced along the ecliptic, then the sun will take about one month to traverse each zodiac constellation.

Section 30674
Exam code: quiz01n3Wb
(A) : 1 student
(B) : students
(C) : 0 students
(D) : 32 students
(E) : 0 students
(F) : 1 student
(No response: 1 student)

Success level: 92% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22


Section 30676
Exam code: quiz01sH0p
(A) : 1 student
(B) : 0 students
(C) : 2 students
(D) : 38 students
(E) : 4 students
(F) : 2 students

Success level: 80% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.31