Astronomy quiz question: lavender/pink and blue nebulae

Astronomy 10 Quiz 11, Fall Semester 2007
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal Q11.1

[Version 1]

[3.0 points.] Which one of the following choices best describes what causes the color of a lavender/pink nebula?
(A) Photons emitted by electrons.
(B) Scattered light from stars.
(C) Blackbody radiation.
(D) Gravitational contraction.
(E) Dark matter.

Correct answer: (A)

The lavender/pink color is the mixture of several visible light photons of different wavelengths, emitted when an electron jumps down several hydrogen orbitals.

Student responses
Section 0135
(A) : 17 students
(B) : 9 students
(C) : 3 students
(D) : 2 students
(E) : 1 student

[Version 2]

[3.0 points.] Which one of the following choices best describes what causes the color of a blue nebula?
(A) Photons emitted by electrons.
(B) Scattered light from stars.
(C) Blackbody radiation.
(D) Gravitational contraction.
(E) Dark matter.

Correct answer: (B)

Very small dust particles will scatter short wavelengths of light more than long wavelengths. Thus red light will typically pass through this type of nebula, while blue light will be scattered in all directions.

Student responses
Section 1073
(A) : 12 students
(B) : 27 students
(C) : 1 student
(D) : 0 students
(E) : 2 students