PH109 Exploring the Universe, Test 1, Fall, 1998
NAME______
Please indicate the best answer to the folowing questions on the answer sheet provided. All questions are worth 2 points unless noted otherwise.
1. How long does a complete precession cycle take?
a) 60,000 years, b) 26,000 years, c) 6000 years, d) 4 years
2. How many astronomical units are there between the Earth and sun?
a) One, b) Ten, c) One million, d) Six trillion
3. The cornerstones of the scientific method are:
a) Creative thought, theory, and mathematical analysis., b) Observation, theory, and testing.
c) Observation only., d) Mathematical analysis, prediction, and careful study.
4. The Ptolemaic model of the universe:
a ) explained and predicted the motions of the planets to some degree.,
b) Is the basis of our modern cosmology.
c) Describes the orbits of the planets as ellipses.
d) was used to explain retorgrade motion
5. The Ptolemaic picture of the universe probably survived for so long because:
a) It is correct.
b) It is consistent with the doctrines of the Church.
c) It worked perfectly in explaining the motions of the planets.
d) It was based on precise measurements of planetary positions.
6. Which of the following is one of the many contributions made by Galileo to astronomy?
a) He discovered that the planets move around the Sun in elliptical orbits.
b) He developed a theory of gravity that could explain orbital motion.
c) He said that the Earth is not at the center of the universe.
d) He used a telescope to observe the heavens, thereby reinforcing the notion of heliocentricity.
7. What was one of Newton's contributions to astronomy?
a) He discovered that the planets move around the Sun in elliptical orbits.
b) He developed a theory of gravity that could explain orbital motion.
c) He said that the Earth is not at the center of the universe.
d) He used a telescope to observe the heavens, thereby reinforcing the notion of heliocentricity.
8. The force of gravity between two objects:
a) Increases with the mass of the objects and decreases with the distance between them.
b) Decreases with the mass of the objects and increases with the distance between them.
c) Increases with the mass of the objects and the distance between them.
d) Decreases with the mass of the objects and the distance between them.
9. The Moon is growing more full each night. This is called _____.
a) gibbous, b) waxing, c) waning, d) phases
10. The distance between two massive objects quadruples. By what factor is the gravitational force between them changed?
a) one half, b) one fourth, c) one eighth, d) one sixteenth
11. A wave's frequency triples. By what factor is its wavelength changed?
a) three, b) one (no change), c) one third, d) one ninth
12. A wave has speed 20 m/s and frequency 4 Hz. What is its wavelength?
a) 80 m, b) 20 m, c) 5 m, d) 4 m
13. Light waves differ fundamentally from either water waves or sound waves because:
a) They do not require a material medium., b) They have various wavelengths.
c) They do not travel from place to place instantaneously., d) The amplitude of light never changes.
14. Colors are perceived differently by our eyes because of their different:
a) Speeds., b) Wavelengths., c) Particles., d) Magnetism.
15. Two forms of electromagnetic radiation that penetrate Earth's atmosphere are:
a) X-rays and visible light., b) Gamma rays and radio waves..
c) Ultraviolet and infrared., d) Visible light and radio waves.
16. High-energy astronomers study:
a) Radio waves., b) X-rays and gamma rays.
c) Excited atoms., d) The entire range of radiation from stars.
17. The frequency at which the intensity of a star's light peaks depends on the _____ of the star. (Fill in the blank.)
a) Wavelength, b) Temperature, c) Magnetism, d) Speed toward or away from the observer.
18. What does Wien's Law reveal?
a) White light consists of many different colors.
b) The farther away we look in space, the deeper we are looking into the past.
c) That the hotter the object, the bluer its radiation.
d) No known object can become hot enough to emit high-energy radiation.
19. Space travelers looking out from the front of their spacecraft would note that the light emitted from the star system toward which they were moving seemed to be:
a) Getting redder., b) Getting bluer., c) Staying the same., d) Hotter.
20. What is spectroscopy?
a) An analysis of the way in which atoms absorb and emit light.
b) An observational technique used to measure the brightness of light.
c) An observing technique that electronically records many images of stars and is much more efficient than photography.
d) An method used to increase the resolution of images and remove the blurring effects of the Earth's atmosphere.
21. Spectral lines are sometimes referred to as the stars' "fingerprints" because:
a) Then tend to make patterns like the swirles in a fingerprint
b) Both are unique and characteristic of that which has produced them.
c) No two stars are the same spectra
d) They are displayed as a series of ridges and valleys
22. A hydrogen atom consists of:
a) Three electrons orbiting a proton., b) Two electrons orbiting a proton.
c) One electron orbiting a proton., d) Any number of electrons in unspecified locations.
23. When an electron resides at a greater-than-normal distance from its parent nucleus, the atom is said to be in what state?
a) Ground., b) Excited., c) Extended, d) Ionized
24. Which of the following properties is constant for all types electromagnetic waves?
a) wavelength, b) speed, c) energy, d) frequency
25. Which of the following types of visible light has the highest energy?
a) red, b) orange, c) green, d) violet
26. If an object is moving toward you, what effect do you observe in the spectrum of that object?
a) It appears red-shifted., b) The light appears to be moving faster.
c) All the spectral lines appear broadened., d) It appears blue-shifted.
27. Wien's Law states that the wavelength at which the most radiation is emitted by an object is inversely related to the following.
a) luminosity of the object, b) speed of light, c) size of the object, d) temperature of the object
28. What is emitted from an atom when one of its electrons makes a transition from a higher energy state to a lower energy state?
a) proton, b) photon, c) graviton, d) neutron
29. What is the primary purpose of a telescope?
a) to magnify
b) to separate light into its various wavelengths
c) to measure the intensity of light very accurately
d) to collect a large amount of light and bring it to a focus
30. What is the resolving power of a telescope?
a) its ability to distinguish two adjacent objects in the sky
b) its ability to collect a large amount of light
c) the amount of magnification
d) its ability to separate light into various wavelengths
31. What problem are adaptive optics used to correct?
a) the opacity of the Earth's atmosphere
b) defects in the optics of the telescope
c) slight errors in the telescope's mount to compensate for the Earth's rotation
d) effects of atmospheric turbulence
32. What is "seeing"?
a) It is a measure of the quality of a telescope's optical system.
b) It is a measure of the image quality due to the stability of the air.
c) It is a standard by which astronomers compare and contrast their own eyesight with that of their colleagues.
d) It is a difference related strictly to cold- and warm-weather observing.
33. What is the primary advantage of the Hubble Space Telescope over
ground-based telescopes?
a) It is above the atmosphere., b) It is the largest telescope ever built.
c) Its mirror is the most perfect ever built.., d) Its instruments are more sophisticated than any on Earth.
34. Which of the following has greatly improved the angular resolution of radio maps?
a) Interferometry., b) Schmidt telescope design., c) Spectroscopy., d) Charge-coupled device.
35. A mountain top is a good location for optical and infrared telescopes because the site:
a) Is above much of the atmosphere.,
b) Is closer to astronomical objects.
c) Has cold weather which improves the performance of the instruments.
d) gives astroinomers a break from the busy city life.
36. Refracting telescopes suffer from this type of defect. Light of different wavelengths is focused at different positions.
a) Diffraction limited, b) Seeing, c) Chromatic aberration, d) Refraction
37. What is the apprximate azimuth (az) elevation (el) of a star which is high in the West.
a) az= 180o, el= 90o a) az= 90o, el= 60o a) az= 270o, el=60o a) az= 90o, el= 180o
38. What time of day does the first quarter moon rise?
a) noon, b) sunset, c) midnigth, d) sunrise
39. When people on Earth see a new moon, what phase of the Earth would people on the moon see?
a) new Earth, b) quarter Earth, c) full Earth, d) cressent Earth
40. What is the bright star in the East at sunset this month?
a) Venus, b) Jupiter, c) Mars, d) Vega
41. (10 points) Explain what was significant about Galleo’s observations of the sun, moon, planet Jupiter, and planet Venus.
42. (10 points) Complete the following diagram by labeling the phases of the moon.