1. Prepare your scantron:
Use
a pencil,
not a pen!
Fill in your name and fill the bubbles under
your name.
LAST NAME FIRST, First name second
Put your 4-digit code instead of “IDENTIFICATION NUMBER”.
--- (The last 4 digits of your OleMiss ID.)
Question # 1: answer A
Question # 2: answer C
Question # 3: answer B
Setup:
Pass/fail makeup: Wednesday 5:00 pm
Please take a moment to mute your cell phone!

2. Review questions coming …

3. This question counts double!
sec 10 9 11 13 14 8 12 6 2 1 3 4 15 5 7 16 26 17 27 28 30 29 24 25 23 19 18 20 21 22
Question 4
A nebula usually has a … spectrum.
A dark
B continuous
C ultraviolet.
D emission
E transparent
Next question coming …

4. This question counts double!
sec 10 9 11 13 14 8 12 6 2 1 3 4 15 5 7 16 26 17 27 28 30 29 24 25 23 19 18 20 21 22
Question 5
What is the substance of the photosphere of the Sun?
A Solid.
B Liquid.
C (At least partially) ionized gas.
D Molecules.
E A gas of purely neutral hydrogen atoms
(H, but not H+, or not H2).
Next question coming …

5. This question counts double!
sec 8 9 11 7 10 4 1 2 3 13 6 12 25 30 35 40 14 19 16 15 17 18 45 20 5
Question 6
What is ionization?
A Molecules fall apart into atoms due to heat.
Glowing gas is formed.
B Nuclear processes in stars produce dangerous radiation.
C Atomic nuclei fall apart into neutrons and protons.
A neutron star results.
D Atoms lose (some of) their electrons due to heat or UV
radiation. The substance becomes plasma.
Next question coming …

6. This question counts double!
sec 10 9 11 13 14 8 12 6 2 1 3 4 15 5 7 16 26 25 27 28 30 29 17 24 19 18 23 20 22 21
Question 7
What type of spectrum does a glowing solid body have?
A absorption spectrum.
B emission spectrum.
C continuous spectrum.
D infrared spectrum.
E ultraviolet spectrum.

7. Cosmic rays From Deep Space (??) The Solar Wind protons, electrons
Earth’s
atmosphere and magnetic field
absorb them
(dangerous for astronauts)
very energetic protons & nuclei
Break up into showers
of many less energetic particles
in the atmosphere.
(always present: causes mutations)

8. Questions coming …

9. sec 8 9 10 12 11 7 6 1 2 3 4 13 30 35 40 45 14 25 16 15 18 17 19 20 5
Question 8
Which of the following causes a measurable amount of radiation, present on Earth?
The Solar Wind.
“Deep Space” cosmic rays.
Radiation from nuclear reactors.
Radiation from naturally occurring decays.
A I and III.
B II and IV.
C I, II and III.
D None of the above.
E All of the above.

10. (Joseph von Fraunhofer, 1814)
The device that resolves the colors of light:
the spectroscope
(Joseph von Fraunhofer, 1814)
• Light from telescope enters
slit (to block off stray light)
• Prism (or grating) separates
the colors
• Produces spectrum
on a screen/on a film
(Put this device in a box and
attach it to the telescope)
The spectroscope
Surprise:
The spectrum of the Sun
has black lines:
Some colors are missing!
(Fraunhofer-lines)
Spectrum: each color is a “line”

11. The spectrum of the Sun Absorption lines (“Frauenhofer-lines”),
(Color and b/w version of the same thing.) H H
Absorption lines (“Frauenhofer-lines”),
many in hydrogen wavelengths
Here: colder gas takes out a few colors
Solar atmosphere

12. the chemical composition
Types of spectra
Continuous spectrum
(thermal glow & synchrotron radiation)
Absorption spectrum
(gas illuminated from behind)
Emission spectrum
(rarified gas: fluorescence)
Each chemical element
has its own spectral lines:
A good way to tell
the chemical composition
of a star!

13. The spectra of stars – the effect of photospheric temperature

14. Questions coming …

15. sec 8 9 10 12 11 7 6 1 2 3 4 13 30 35 40 45 14 25 16 15 18 17 19 20 5
Question 9
How do we know that the Sun is made
mainly of hydrogen?
A Its density equals the density of hydrogen.
B Spaceships brought back a samples from the Sun.
C Its spectrum contains hydrogen lines.
D The gravity of the Sun can be explained only by hydrogen gas.
E Only burning hydrogen (and no other gases) can produce enough heat to explain why the Sun is hot.
Next question coming …

16. sec 10 9 11 13 14 8 12 7 2 1 3 4 6 5 15 17 26 25 27 28 30 29 16 24 19 18 23 20 22 21
Question 10
Which one of the following types of spectra
indicate the presence of cold gas located between a star and Earth?
A Absorption spectra.
B Emission spectra.
C Continuous spectra.
D Line spectra.
E Band spectra.

17. sec 10 9 11 12 15 14 13 8 7 1 2 3 5 4 6 16 26 17 27 28 30 29 24 25 23 19 18 20 21 22
Question 11
The spectrum of the Sun consists of
A a few bright lines only.
B dark lines over a bright continuum.
C dark bands of light with bright centers, over a bright continuum.
D a continuous bright spectrum like a rainbow.
E a few bright bands with dark centers.
Next question coming …

18. The effect of movement on spectral lines:
The Doppler effect
• Light source moves towards observer: spectral lines are shifted towards blue
• Light source moves away from observer: spectral lines are shifted towards red
• Light source moves sideways: no change

19. The spectrum of another star
The Sun H H
Polaris
Spectral lines shifted towards blue:
Polaris is approaching us
Measure shift: find radial speed
17 km/s
Why are the spectral lines shifted? -- the Doppler effect

20. Questions coming …

21. sec 8 9 10 12 11 7 6 1 2 3 4 13 30 35 40 45 14 25 16 15 18 17 19 20 5
Question 12
In what are spectra of other stars different from
the Sun’s?
A The same spectral lines are there in every star’s
spectra, but they may be shifted if the star is moving.
B Different spectral lines may be visible, in addition
to Doppler-shift.
C All stars have the same spectrum because they are all
made of gas.
D The spectrum is the same, except that the blue part of hotter stars’ spectra is brighter.
Next question coming …

22. sec 8 9 10 12 11 7 6 1 2 3 4 13 30 35 40 45 14 25 16 15 18 17 19 20 5
Question 13
What is the Doppler effect?
A Stars move on tiny circles in the sky, once a year.
B The stars appear red when they are rising or setting.
C Far-away stars appear red because the Universe is expanding.
D The spectral lines of a star are shifted towards red, if the star is moving away from us, and towards blue, if the star is approaching us.
E A fast moving star’s spectral lines are shifted towards red, independently of the direction of motion.
Next question coming …

23. sec 10 9 11 12 15 14 13 8 7 1 2 3 5 4 6 16 26 17 27 28 30 29 24 25 23 19 18 20 21 22
Question 14
A particular galaxy is moving away from us with large
speed. Which of the following happens to its spectrum?
A The spectral lines show up shifted towards red.
B The spectral lines show up shifted towards blue.
C The color of the galaxy becomes redder.
D The color of the galaxy becomes bluer.
Next question coming …

24. sec 10 9 11 13 14 8 12 7 2 1 3 4 6 5 15 17 26 25 27 28 30 29 16 24 19 18 23 20 22 21
Question 15
Which of the following happens to the sound of the whistle coming from a train approaching us at high speed?
A It becomes lower-pitched.
B It becomes higher-pitched.
C It becomes less loud.
D It becomes more loud.

25. Turn in your scantron now
personally!