Astronomy quiz archive: stellar evolution

Astronomy 210 Quiz 5, spring semester 2012
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz05nArf
Section 30674

0- 8.0 :	* [low = 7.0]
8.5-16.0 :	*****
16.5-24.0 :	********* [mean = 23.1 +/- 6.9]
24.5-32.0 :	**************
32.5-40.0 :	*** [high = 36.5]

Section 30676, version 1
Exam code: quiz05spH3
Section 30676

0- 8.0 :	** [low = 7.0]
8.5-16.0 :	*******
16.5-24.0 :	**************** [mean = 21.2 +/- 6.8]
24.5-32.0 :	************
32.5-40.0 :	* [high = 40.0]

Physics quiz archive: capacitors, circuits

Physics 205B Quiz 4, spring semester 2012
Cuesta College, San Luis Obispo, CA

Section 30882, version 1
Exam code: quiz04j0uL

Section 30882 results
Quiz 4 results (max score = 30):

0- 6 :	* [low = 6]
7-12 :	****
13-18 :	********
19-24 :	***** [mean = 20.0 +/- 6.8]
25-30 :	******** [high = 30]

Physics midterm problem: direct wave and phase-shifted in-line reflection interference

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

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problems 25.1, 25.3

[20 points.] A radio transmitter sends a signal of wavelength 0.80 km to a receiver 1.40 km away. The signal also travels from the transmitter to the receiver by another path where it reflects with a 180° phase shift from a metal skyscraper. (Drawing is not to scale.) As a result, there is a constructive signal at the receiver. Find the shortest possible (non-zero) distance between the receiver and the skyscraper. Show your work and explain your reasoning.


Solution and grading rubric:

• p = 20/20:
  Correct. Applies constructive interference for out-of-phase sources Δl = (m + (1/2))·λ, where path difference Δl = 2·x. Solving for the distance between the receiver and skyscraper x = (m + (1/2))·(λ/2), and setting m = 0 to find the smallest value for x = λ/4 = 0.20 km.
  
• r = 16/20:
  Nearly correct, but includes minor math errors. Sets m = 1, and finds the next smallest value for x = 0.60 km, or has Δl = x instead of 2·x.
  
• t = 12/20:
  Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. At least applies correct constructive interference for out-of-phase condition.
  
• v = 8/20:
  Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Some attempt at connecting interference conditions to path difference.
  
• x = 4/20:
  Implementation of ideas, but credit given for effort rather than merit.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
Section 30882
Exam code: midterm01o1Ls
p: 4 students
r: 5 students
t: 8 students
v: 4 students
x: 5 students
y: 1 student
z: 0 students

A sample "p" response (from student 6969):

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 4, spring semester 2012
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz04noR3
Section 30674

0- 8.0 :
8.5-16.0 :	*** [low = 13.0]
16.5-24.0 :	*******
24.5-32.0 :	************* [mean = 26.4 +/- 6.2]
32.5-40.0 :	******** [high = 36.5]

Section 30676, version 1
Exam code: quiz04sLO8
Section 30676

0- 8.0 :
8.5-16.0 :	*** [low = 12.0]
16.5-24.0 :	******************** [mean = 22.3 +/- 6.3]
24.5-32.0 :	********
32.5-40.0 :	**** [high = 40.0]

Astronomy midterm question: early evening spring Big Dipper

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

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

Kory: When [is the Big Dipper] visible [for an observer] in the [n]orthern [h]emisphere?
Tina L: [T]he [B]ig [D]ipper is highest in the early evening in the spring.

Discuss whether or not this answer is correct, and how you know this. Support your answer using a diagram showing the positions of the sun, moon, Earth, and an observer on Earth.

*Source: http://answers.yahoo.com/question/index;_ylt=Amy1qc2j.2ZPKhnXSiujkkojzKIX;_ylv=3?qid=20090217172556AANBQlF.

Solution and grading rubric:

• p = 20/20:
  Correct. Clearly explains how the Big Dipper cannot be highest in the early evening spring sky. Specifically chooses a plausible "spring" month and "early evening" time on the starwheel and finds position of the Big Dipper is not very near the zenith, or instead places the Big Dipper near zenith, and finds that a plausible "spring" month cannot line up with an "early evening" time. Or may stretch the boundaries of "spring" months or "early evening" times to find Big Dipper near zenith, making this plausible.
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. May indicate when the Big Dipper is highest during a non-spring, non-early evening date/time instead.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Argument based on the Big Dipper being a circumpolar constellation, such that would be visible during any night of the year, but does not address plausibility of "highest in the early evening in the spring" statement. Or vague description of "spring" months or "early evening" times, or specifies date/time such that the Big Dipper is actually at lowest point in sky.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Substantive discussion, but missing/problematic diagram.
  
• x = 4/20:
  Implementation/application of ideas, but credit given for effort rather than merit. Uses starwheel, but reports
  inconsistent/incomplete date/time/position information.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
Section 30676
Exam code: midterm01s0Be
p: 16 students
r: 3 students
t: 12 students
v: 10 students
x: 0 students
y: 0 students
z: 1 student

A sample "p" response (from student 1449):
Another sample "p" response (from student 1339):

Astronomy midterm question: afternoon visible moon?

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

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

Wishes are Fishes: Have you ever seen the sun and moon in the sky at the same time?
hellas: Yes[,] ...in the afternoon...when the sun [is] not completely down yet and the moon has already showed up!

Discuss whether or not this answer is correct, and how you know this. Support your answer using a diagram showing the positions of the sun, moon, Earth, and an observer on Earth.

*Source: http://answers.yahoo.com/question/index;_ylt=Amy1qc2j.2ZPKhnXSiujkkojzKIX;_ylv=3?qid=20090212025123AAUCKmF.

Solution and grading rubric:

• p = 20/20:
  Correct. Any waxing phase (waxing crescent, first quarter, waxing gibbous) would rise after 12 PM, and still be visible in the sky during sunset at 6 PM. Correct diagram and reasoning. May argue (nearly) full moon or waning phases in addition to waxing phases, with appropriate diagrams/reasoning.
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Or discusses only phases visible during the morning.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problems with either diagram or discussion.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Substantive discussion, but missing/problematic diagram.
  
• x = 4/20:
  Implementation/application of ideas, but credit given for effort rather than merit. Problematic discussion, diagrams with the moon orbiting the sun, etc.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
Section 30676
Exam code: midterm01s0Be
p: 17 students
r: 15 students
t: 9 students
v: 5 students
x: 6 students
y: 0 students
z: 0 students

A sample "p" response (from student 6196):
Another sample "p" response (from student 7989), with another possible phase, visible in the morning:
A sample "p" response (from student 0308), discussing the (nearly) full moon, coincidentally occurring just before the start of this midterm:

Astronomy midterm question: "good beginner telescope" size

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

[20 points.] An astronomy question on an online discussion board(*) was asked and answered:

ahriik: What is a good telescope for a beginner? I want to get into astronomy, so I believe a telescope is essential.
eri:[F]or a good beginner telescope; the most important factor is the size of the primary mirror... There's not much point in investing in a telescope if the primary mirror diameter is less than 4.5", and the bigger the better...

Discuss reasons why "there's not much point in investing" in a small diameter telescope. Support your answer using the properties of telescope parameters and telescope powers.

*Source: http://answers.yahoo.com/question/index;_ylt=ArVtg7r0DwT2ZpjF5GpF2_sjzKIX;_ylv=3?qid=20100520162052AASAINW.

Solution and grading rubric:

• p = 20/20:
  Correct. Discusses how diameter of primary lens/mirror determines the light-gathering power and resolving power, such that a large diameter lens/mirror would result in bright, finely resolved images worth magnifying.
  
• r = 16/20:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Discusses how diameter affects either light-gathering power or resolving power, other diameter/power discussion incomplete.
  
• t = 12/20:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Problematic discussion of how diameter is related to either light-gathering power or resolving power.
  
• v = 8/20:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least discusses some connection between telescope parameters and telescope power.
  
• x = 4/20:
  Implementation/application of ideas, but credit given for effort rather than merit. Does not discuss connection between telescope parameters and telescope powers.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
Section 30674
Exam code: midterm01neE7
p: 18 students
r: 14 students
t: 0 students
v: 1 student
x: 0 students
y: 0 students
z: 0 students

Section 30676
Exam code: midterm01s0Be
p: 21 students
r: 15 students
t: 1 student
v: 3 students
x: 1 student
y: 1 student
z: 0 students

A sample "p" response (from student 4490):
Another sample "p" response (from student 0010):