Chapter 5
The Birth of Astrophysics
1. In observing a neon advertising sign with a spectroscope, you would expect to see a:
A. continuous spectrum.
B. dark-line (absorption) spectrum.
C. bright-line (emission) spectrum.
D. no spectrum at all because the neon is in glass.
2. In general, the observed spectra of stars appear as what kind of spectrum?
A. Absorption.
B. Continuous.
C. Emission.
D. Nonthermal.
3. If you view the light from an opaque, hot gas through a spectroscope, you would expect to see
what kind of spectrum?
A. Continuous.
B. Emission line.
C. Absorption line.
D. Combination of emission line and continuous.
4. If you view the light from a transparent, hot gas through a spectroscope, you would expect to see
what kind of spectrum?
A. Continuous.
B. Emission line.
C. Absorption line.
D. Combination of absorption line and continuous.
5. Which of the following has the LOWEST frequency?
A. X-rays.
B. Visible light.
C. Radio waves.
D. Infrared.
6. Which of the following has the LONGEST wavelength?
A. Red light.
B. Blue light.
C. Green light.
D. Infrared light.
7. Compared to radio waves, ultraviolet light:
A. travels faster.
B. has a longer wavelength.
C. has more energy per photon.
D. has a lower frequency.
8. In the overall electromagnetic spectrum, consider radio, visible light, and gamma rays in terms of
their wavelength. Their correct order, from longest to shortest, is:
A. radio, visible, gamma rays.
B. gamma rays, visible, radio.
C. visible, gamma rays, radio.
D. visible, radio, gamma rays.
9. In the energy-level model for the interaction of atoms and light, when an atom absorbs light at a
specific wavelength:
A. an electron drops down one energy level.
B. the atom captures a free electron.
C. an electron jumps up an energy level.
D. the nucleus of the atom changes energy levels.
10. When an atom is excited, then it has:
A. more electrons than protons.
B. the same number of electrons as protons.
C. one or more electrons stripped off.
D. one or more electrons move up energy levels.
11. The Balmer series for hydrogen is:
A. the sequence of lines from ionized hydrogen.
B. transitions from the ground to first excited state.
C. transitions to and from the first excited state.
D. transitions to and from the second excited state.
12. When you see a spectrum with absorption lines in it, you can infer that:
A. the light passed through ionized atoms.
B. electrons moved up in energy levels to absorb the light.
C. electrons moved down in energy levels to absorb the light.
D. all the atoms were in excited states.
13. Atoms emitting and absorbing light show the conservation of energy because an atom:
A. gains energy when it absorbs light.
B. loses energy when it emits light.
C. gains energy equal to that of the absorbed photon.
D. gains more energy than that of the absorbed photon.
14. When we used the diffraction gratings to view hydrogen's spectra we observed:
A. a continuous spectrum.
B. emission lines only.
C. absorption lines only.
D. emission lines on a continuous spectrum.
15. In general, the observed spectra of stars appear as what kind of spectrum?
A. Absorption.
B. Continuous with absorption features.
C. Emission.
D. Nonthermal.
16. In astronomy, ONE reason that we observe broadened (or smeared) emission and absorption
lines is because:
A. the simple Bohr model allows for multiple electron orbital transitions.
B. the quantum nature of light is violated.
C. of the complex nature of atoms and molecules slightly changes the simplified Bohr
energy levels.
D. the continuous spectrum is weak.
17. When we look at the continuous spectrum of our sun, we see dark features (lines) that are
caused by the absorption of sunlight of a particular wavelength by:
A. a hot opaque gas near the surface of the sun.
B. a cool transparent gas between us and the sun.
C. a cold, fermented malt beverage.
D. an absorption spectrum.
18. When viewing hot nitrogen gas through a spectroscope, you observe:
A. a continuous spectrum.
B. a dark-line (absorption) spectrum.
C. a bright-line (emission) spectrum.
D. a spectrum similar to our Sun's spectrum.
19. Which of the following has the HIGHEST frequency?
A. X-rays.
B. Visible light.
C. Radio waves.
D. Gamma rays.
20. In the visible spectrum, which of the following has the SHORTEST wavelength?
A. Red light.
B. Blue light.
C. Green light
D. Ultraviolet light.
21. In the energy-level model for the interaction of atoms and light, when an atom EMITS light at a
specific wavelength:
A. an electron drops down one energy level.
B. an electron jumps up an energy level.
C. the nucleus of the atom changes energy levels.
D. nothing happens to the atom.
22. If an ionized atom captures an electron:
A. the atom gets larger.
B. light of a discrete wavelength is emitted.
C. a photon is absorbed by the atom.
D. the atom becomes a isotope.
23. In science, we do NOT describe light as:
A. electromagnetic radiation with a characteristic wavelength.
B. electromagnetic radiation with a characteristic frequency.
C. a particle (photon) consisting of a quanta of energy.
D. a ray of energy moving only in a straight line.
24. Some of the electromagnetic radiation is absorbed by the earth's atmosphere. The types
reaching sea level are mostly:
A. X-rays and gamma rays.
B. X-rays and ultra violet.
C. ultraviolet and infrared.
D. visible and some radio.
25. If you view white light through a spectroscope (like a prism), you would expect to see what
kind of spectrum?
A. Combination of emission line and continuous.
B. Continuous.
C. Emission line.
D. Absorption line.
26. When we used the diffraction gratings to view the spectrum produced by hydrogen gas we
observed:
A. a continuous spectrum.
B. emission lines only.
C. absorption lines only.
D. emission lines on a continuous spectrum.
27. Vega is almost twice as hot as the Sun in its photosphere. Its color is _______ but most of its
radiation is really____________:
A. red, infrared.
B. blue, radio.
C. white, ultraviolet.
D. orange, microwave.
28. Antares is about half the Sun's temperature at its photosphere. Its color is __________ but most
of its energy is really_____________:
A. red-orange, infrared.
B. deep red, microwave.
C. blue, ultraviolet.
D. there is no relation between color and temperature.
29. Which of these instruments best detects the chemistry of the stars?
A. Charge coupled devices.
B. Photometers.
C. Spectrographs.
D. Bolometers.
ESSAYS
1. Explain why a nebula shows emission lines, but the spectra of most stars contain absorption lines
instead.
2. Describe the connection between the temperature of a star and its apparent color.
3. In observing the stars visually, we are only seeing the "tip of the iceberg". Relate this statement
to the new windows in astronomy opened up by space exploration.