Astronomy midterm question: determining distance from apparent and absolute magnitudes (1)

Astronomy 210 Midterm 2, fall semester 2019
Cuesta College, San Luis Obispo, CA

The following claim was made by a student on an astronomy exam[*]:

0725: Let's say a star had an apparent magnitude of –1.5 and an absolute magnitude of +1.5. The star has to be closer than 10 parsecs from Earth.

Discuss whether this claim is correct or incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] waiferx.blogspot.com/2008/11/astronomy-midterm-question-apparent.html.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, while at its actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed at the "fair comparison distance" of 10 parsecs away), and discusses:
  1. the star's apparent magnitude of m = −1.5 is brighter than its absolute magnitude of M = +1.5; so
  2. the star must be located closer than 10 parsecs away, as moving it from its actual location (where m = −1.5) to 10 parsecs (where M = +1.5) makes it dimmer; such that
  3. the student's claim is correct.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Has both (1)-(2) complete and correct, but somehow concludes that student's claim is incorrect, or does not sufficiently discuss the correctness/incorrectness about the student's claim.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances. Has only one of (1)-(2) complete and correct, the other is problematic.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances. Both (1) and (2) are problematic.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70158
Exam code: midterm02Rf0w
p: 23 students
r: 4 students
t: 1 student
v: 0 students
x: 6 students
y: 0 students
z: 0 students

A sample "p" response (from student 1492):

Astronomy midterm question: determining distance from apparent and absolute magnitudes (2)

Astronomy 210 Midterm 2, fall semester 2019
Cuesta College, San Luis Obispo, CA

The following claim was made by a student on an astronomy exam[*]:

7734: If a star has an absolute magnitude of +20, but when seen from Earth has an apparent magnitude of +5, the star must be very close to us.

Discuss why this claim is incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] waiferx.blogspot.com/2010/11/astronomy-midterm-question-apparent.html.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, while at its actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed at the "fair comparison distance" of 10 parsecs away), and discusses:
  1. the star's apparent magnitude of m = +5 is brighter than its absolute magnitude of M = +20; so
  2. the star must be located closer than 10 parsecs away, as moving it from its actual location (where m = +5) to 10 parsecs (where M = +20) makes it dimmer; such that
  3. the student's claim is correct.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Has both (1)-(2) complete and correct, but somehow concludes that student's claim is incorrect, or does not sufficiently discuss the correctness/incorrectness about the student's claim.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances. Has only one of (1)-(2) complete and correct, the other is problematic.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances. Both (1) and (2) are problematic.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70160
Exam code: midterm02T4qz
p: 7 students
r: 4 students
t: 6 students
v: 3 students
x: 2 students
y: 0 students
z: 0 students

A sample "p" response (from student 5622):

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, fall semester 2019
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz05Sh0w


Section 70158

0- 8.0   :
8.5-16.0 :	*** [low = 10.0]
16.5-24.0 :	*
24.5-32.0 :	********* [mean = 32.0 +/- 8.2]
32.5-40.0 :	******************* [high = 40.0]

Section 70160, version 1
Exam code: quiz05NpRm


Section 70160

0- 8.0   :
8.5-16.0 :	* [low = 16.0]
16.5-24.0 :	**********
24.5-32.0 :	***** [mean = 26.0 +/- 7.5]
32.5-40.0 :	****** [high = 40.0]

Astronomy midterm question: comparing distances from apparent and absolute magnitudes (1)

Astronomy 210 Midterm 2, spring semester 2019
Cuesta College, San Luis Obispo, CA

The following claim was made by a student on an astronomy exam[*]:

1022: For example, a star could have an apparent magnitude of –3 and an absolute magnitude of +8. This star would be closer to Earth than a star with an apparent magnitude of +8 and an absolute magnitude of +3.

Discuss why this claim is correct, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] waiferx.blogspot.com/2013/05/astronomy-midterm-question-relative.html.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed at the "comparison distance" of 10 parsecs away), and discusses:
  1. the m = −3, M = +8 star must be closer than 10 parsecs away, as moving it from its actual location to 10 parsecs makes it dimmer; and
  2. the m = +8, M = +3 star must be farther than 10 parsecs away, as moving it from its actual location to 10 parsecs makes it brighter; such that
  3. the m = −3, M = +8 star must be located closer to Earth than the m = +8, M = +3 star.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 30674
Exam code: midterm02nwF7
p: 19 students
r: 1 student
t: 7 students
v: 4 students
x: 2 students
y: 0 students
z: 0 students

A sample "p" response (from student 2815):

Astronomy midterm question: comparing distances from apparent and absolute magnitudes (2)

Astronomy 210 Midterm 2, spring semester 2019
Cuesta College, San Luis Obispo, CA

The following claim was made by a student on an astronomy exam[*]:

1022: For example, a star could have an apparent magnitude of –3 and an absolute magnitude of +8. This star would be farther away from Earth than a star with an apparent magnitude of +8 and an absolute magnitude of +3.

Discuss why this claim is incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] waiferx.blogspot.com/2013/05/astronomy-midterm-question-relative.html.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed at the "comparison distance" of 10 parsecs away), and discusses:
  1. the m = −3, M = +8 star must be closer than 10 parsecs away, as moving it from its actual location to 10 parsecs makes it dimmer; and
  2. the m = +8, M = +3 star must be farther than 10 parsecs away, as moving it from its actual location to 10 parsecs makes it brighter; such that
  3. the m = −3, M = +8 star must be located closer to Earth than the m = +8, M = +3 star.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 30676
Exam code: midterm02SpsR
p: 26 students
r: 2 students
t: 5 students
v: 5 students
x: 4 students
y: 0 students
z: 0 students

A sample "p" response (from student 4815):

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, spring semester 2019
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz05NiR0


Section 30674

0- 8.0   :
8.5-16.0 :	**** [low = 11.0]
16.5-24.0 :	***********
24.5-32.0 :	****** [mean = 26.2 +/- 8.7]
32.5-40.0 :	********** [high = 40.0]

Section 30676, version 1
Exam code: quiz05S4re


Section 30676

0- 8.0   :	** [low = 2.5]
8.5-16.0 :	**
16.5-24.0 :	********
24.5-32.0 :	*********** [mean = 27.6 +/- 9.2]
32.5-40.0 :	*************** [high = 40.0]

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, fall semester 2018
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz05T3rA


Section 70158

0- 8.0   :	* [low = 8.0]
8.5-16.0 :	**
16.5-24.0 :	*********
24.5-32.0 :	********** [mean = 26.3 +/- 7.6]
32.5-40.0 :	*********** [high = 40.0]

Section 70160, version 1
Exam code: quiz05Oor7


Section 70160

0- 8.0   :	* [low = 8.0]
8.5-16.0 :	****
16.5-24.0 :	******** [mean = 20.1 +/- 6.7]
24.5-32.0 :	***
32.5-40.0 :	* [high = 36.0]

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, spring semester 2018
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz05NoPw


Section 30674

0- 8.0   :
8.5-16.0 :	* [low = 14.5]
16.5-24.0 :	*****
24.5-32.0 :	****** [mean = 27.6 +/- 7.1]
32.5-40.0 :	******* [high = 40.0]

Section 30676, version 1
Exam code: quiz05So1L


Section 30676

0- 8.0 :	**** [low = 4.0]
8.5-16.0 :	******
16.5-24.0 :	******
24.5-32.0 :	*************** [mean = 24.7 +/- 10.3]
32.5-40.0 :	*********** [high = 40.0]

Astronomy midterm question: apparent magnitude dimmer than absolute magnitude?

Astronomy 210 Midterm 2, fall semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked:

Qu: If the distance to a star is 20 parsecs, and its absolute magnitude is +5.5, what is its apparent magnitude?
day: The apparent magnitude would be dimmer than +5.5.

Discuss whether this answer is correct or incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] answers.yahoo.com/question/index?qid=20100615201717AAZwXu7.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude (M (brightness as seen from Earth, when placed at the "fair comparison distance" of 10 parsecs away). Discusses how this star with an absolute magnitude value of +5.5 (measured at 10 parsecs) will get dimmer when placed farther away to 20 parsecs, and thus its apparent magnitude will be dimmer than its absolute magnitude of +5.5. Then makes conclusion on correctness of response.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. As (p), but does not explicitly determine incorrectness of response.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70158
Exam code: midterm02Sm5n
p: 27 students
r: 7 students
t: 10 students
v: 1 student
x: 1 student
y: 0 students
z: 0 students

A sample "p" response (from student 1027):

Astronomy midterm question: apparent magnitude brighter than absolute magnitude?

Astronomy 210 Midterm 2, fall semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked:

Qu: If the distance to a star is 20 parsecs, and its absolute magnitude is +5.5, what is its apparent magnitude?
day: The apparent magnitude would be brighter than +5.5.

Discuss whether this answer is correct or incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] answers.yahoo.com/question/index?qid=20100615201717AAZwXu7.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude (M (brightness as seen from Earth, when placed at the "fair comparison distance" of 10 parsecs away). Discusses how this star with an absolute magnitude value of +5.5 (measured at 10 parsecs) will get dimmer when placed farther away to 20 parsecs, and thus its apparent magnitude will be dimmer than its absolute magnitude of +5.5. Then makes conclusion on incorrectness of response.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. As (p), but does not explicitly determine incorrectness of response.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70160
Exam code: midterm02nJv3
p: 24 students
r: 3 students
t: 3 students
v: 1 student
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 7237):

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, fall semester 2017
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz05Sbn3


Section 70158

0- 8.0   :	* [low = 4.0]
8.5-16.0 :	*
16.5-24.0 :	*************
24.5-32.0 :	************* [mean = 27.6 +/- 8.3]
32.5-40.0 :	*************** [high = 40.0]

Section 70160, version 1
Exam code: quiz05n3Rw


Section 70160

0- 8.0 :	** [low = 1.0]
8.5-16.0 :	***
16.5-24.0 :	*****
24.5-32.0 :	*********** [mean = 25.5 +/- 9.1]
32.5-40.0 :	******* [high = 40.0]

Astronomy midterm question: same absolute magnitude stars, different distances closer than 10 parsecs?

Astronomy 210 Midterm 2, spring semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked and answered:

Pdg: Can two stars have the same absolute magnitude, if they both have different distances closer than 10 parsecs?
pub: Yes, if the nearer star has a brighter apparent magnitude (bigger negative number, or smaller positive number), and the farther star has a dimmer apparent magnitude.

Discuss whether this answer is correct or incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] answers.yahoo.com/question/index?qid=20170305023512AAeRXO8.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed at the "fair comparison distance" of 10 parsecs away), and discusses:
  1. a star 10 parsecs away with a certain absolute magnitude will get brighter when placed closer than 10 parsecs away from Earth, and thus its apparent magnitude will be brighter than its absolute magnitude; and
  2. since both stars have the same absolute magnitude at 10 parsecs, the nearer star would be located much closer than 10 parsecs, resulting in a much brighter apparent magnitude, while the farther star would be located just a little closer than 10 parsecs, resulting in only a slightly brighter apparent magnitude, dimmer than the other star.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. May have one star located closer than 10 parsecs, or moving in the wrong direction to change its apparent magnitude to its absolute magnitude.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 30674
Exam code: midterm02nDcc
p: 13 students
r: 2 students
t: 2 students
v: 4 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 7697):
Another sample "p" response (from student 5150):

Astronomy midterm question: same absolute magnitude stars, different distances farther than 10 parsecs?

Astronomy 210 Midterm 2, spring semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked and answered:

Pdg: Can two stars have the same absolute magnitude, if they both have different distances farther than 10 parsecs?
pub: Yes, if the nearer star has a brighter apparent magnitude (bigger negative number, or smaller positive number), and the farther star has a dimmer apparent magnitude.

Discuss whether this answer is correct or incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] answers.yahoo.com/question/index?qid=20170305023512AAeRXO8.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed at the "fair comparison distance" of 10 parsecs away), and discusses:
  1. a star at 10 parsecs away with a certain absolute magnitude will get dimmer when placed further than 10 parsecs away from Earth, and thus its apparent magnitude will be dimmer than its absolute magnitude; and
  2. since both stars have the same absolute magnitude at 10 parsecs, the nearer star would be located just a little farther away from 10 parsecs, resulting in a slightly dimmer apparent magnitude, while the farther star would be located much farther away from 10 parsecs, resulting in a much dimmer apparent magnitude.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. May have one star located closer than 10 parsecs, or moving in the wrong direction to change its apparent magnitude to its absolute magnitude.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 30676
Exam code: midterm02sL0w
p: 18 students
r: 6 students
t: 4 students
v: 9 students
x: 6 students
y: 0 students
z: 0 students

A sample "p" response (from student 0428):
Another sample "p" response (from student 0511):

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, spring semester 2017
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz05ne0W


Section 30674

0- 8.0 :	* [low = 8.0]
8.5-16.0 :	*
16.5-24.0 :	***
24.5-32.0 :	************ [mean = 26.8 +/- 7.5]
32.5-40.0 :	***** [high = 40.0]

Section 30676, version 1
Exam code: quiz05s4Ha


Section 30676

0- 8.0 :	* [low = 1.5]
8.5-16.0 :	****
16.5-24.0 :	**********
24.5-32.0 :	************** [mean = 26.5 +/- 7.9]
32.5-40.0 :	************ [high = 40.0]

Astronomy midterm question: stars with absolute magnitude brighter than apparent magnitude

Astronomy 210 Midterm 2, fall semester 2016
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked and answered:

un: Is the absolute magnitude of some stars brighter than their apparent magnitude?
Pa: That is the case for stars that are a long way away.

Discuss why this answer is correct, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] answers.yahoo.com/question/index?qid=20121011172202AAobQUe.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed at the "fair comparison distance" of 10 parsecs away), and discusses either of two arguments:
  1. a star farther than 10 parsecs ("a long way away") with a certain apparent magnitude will get brighter when brought closer up to 10 parsecs away from Earth, and thus its absolute magnitude will be brighter than its apparent magnitude; or
  2. a star at 10 parsecs away with a certain absolute magnitude will get dimmer when placed further away than 10 parsecs away from Earth, and thus its apparent magnitude will be dimmer than its absolute magnitude.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes, and distances.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 70158
Exam code: midterm02sU6A
p: 34 students
r: 0 students
t: 1 student
v: 1 student
x: 0 students
y: 0 students
z: 0 students

Section 70160
Exam code: midterm02NbnW
p: 14 students
r: 1 student
t: 5 students
v: 4 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 9135):
A sample "p" response (from student 3168):

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, fall semester 2016
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz05s4nD


Section 70158

0- 8.0   :	** [low = 4.0]
8.5-16.0 :	**
16.5-24.0 :	***************
24.5-32.0 :	********* [mean = 26.9 +/- 6.9]
32.5-40.0 :	******** [high = 36.5]

Section 70160, version 1
Exam code: quiz05n0Ko


Section 70160

0- 8.0 :	* [low = 8.0]
8.5-16.0 :	****
16.5-24.0 :	************
24.5-32.0 :	******************* [mean = 27.5 +/- 7.3]
32.5-40.0 :	*************** [high = 40.0]

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, spring semester 2016
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz05nUL7


Section 30674

0- 8.0   :
8.5-16.0 :	*** [low = 12.0]
16.5-24.0 :	*******
24.5-32.0 :	** [mean = 25.9 +/- 8.8]
32.5-40.0 :	******* [high = 40.0]

Section 30676, version 1
Exam code: quiz05sPrB


Section 30676

0- 8.0 :	* [low = 8.0]
8.5-16.0 :	****
16.5-24.0 :	************
24.5-32.0 :	******************* [mean = 27.5 +/- 7.3]
32.5-40.0 :	*************** [high = 40.0]

Astronomy midterm question: ranking distances given apparent magnitudes, absolute magnitudes

Astronomy 210 Midterm 2, fall semester 2015
Cuesta College, San Luis Obispo, CA

The apparent magnitudes and absolute magnitudes of three stars are listed below.

	m apparent magnitude	M absolute magnitude
Avior	+1.9	–4.5
Benetnash	+1.9	–3.0
Tau Ceti	+3.5	+5.7

Determine which star is farthest away (or indicate a tie, if any). Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed 10 parsecs away), and compares:
  1. how star A (Avior) and star B (Benetash) appear equally bright (same apparent magnitude m), but star A is brighter than star B when both are placed at 10 parsecs away from Earth (brighter absolute magnitude), thus star A had to be moved a greater distance closer to Earth than star B; and
  2. how star C (Tau Ceti) appears dimmer than star A and star B (dimmer apparent magnitude m), and when star C is moved further back to 10 parsecs away from Earth, it will be even dimmer than star A and star B at 10 parsecs (and thus star C is the closest of these three stars).
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Discusses (1), but does not discuss (2).
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances. May have order of brightnesses reversed, picking star C as having the brightest absolute magnitude.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes,
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Section 70160
Exam code: midterm02sP3c
p: 27 students
r: 3 students
t: 9 students
v: 2 students
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 1022):

Astronomy midterm question: ranking absolute magnitudes given apparent magnitudes, distances

Astronomy 210 Midterm 2, fall semester 2015
Cuesta College, San Luis Obispo, CA

The apparent magnitudes and distances of three stars are listed below.

	m apparent magnitude	d distance from Earth
Avior	+1.9	190 pcs
Benetnash	+1.9	32 pcs
Tau Ceti	+3.5	4 pcs

Determine which star has the brightest absolute magnitude (or indicate a tie, if any). Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

Solution and grading rubric:

• p:
  Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute magnitude M (brightness as seen from Earth, when placed 10 parsecs away), and compares:
  1. how star A (Avior) and star B (Benetash) appear equally bright (same apparent magnitude m), but star A is brighter than star B when both are placed at 10 parsecs away from Earth (and thus has a brighter absolute magnitude), as star A will be moved a greater distance closer to Earth than star B; and
  2. how star C (Tau Ceti) appears dimmer than star A and star B (dimmer apparent magnitude m), and when star C is moved further back to 10 parsecs away from Earth, it will be even dimmer than star A and star B at 10 parsecs (and thus star C has the dimmest absolute magnitude of these three stars).
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Discusses (1), but does not discuss (2).
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least discussion demonstrates understanding of relationships between apparent magnitudes, absolute magnitudes, and distances. May have order of brightnesses reversed, picking star C as having the brightest absolute magnitude.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute magnitudes, and distances.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute magnitudes,
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Section 70160
Exam code: midterm02n1N0
p: 18 students
r: 3 students
t: 5 students
v: 1 student
x: 0 students
y: 0 students
z: 0 students

A sample "p" response (from student 3030):
A sample "p" response (from student 5555):

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, fall semester 2015
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz05s3T1


Section 70158

0- 8.0   :
8.5-16.0 :	****** [low = 12.0]
16.5-24.0 :	***********
24.5-32.0 :	*********** [mean = 25.9 +/- 7.7]
32.5-40.0 :	************ [high = 36.5]

Section 70160, version 1
Exam code: quiz05ne7A


Section 70160

0- 8.0 :
8.5-16.0 :	******** [low = 11.0]
16.5-24.0 :	********* [mean = 21.7 +/- 8.5]
24.5-32.0 :	****
32.5-40.0 :	**** [high = 40.0]