Download a light year is

PH109 Exploring the Universe, Test #1, Spring, 2000
NAME_____________________________________
Indicate the best answer to the following questions on the answer sheet provided. Please
answer the essay questions on this copy of the test. All questions are worth 2 points
unless noted otherwise.
1. A light year is
a) the characteristic size of light , b) the distance the Earth travels around the sun in one year
c) the distance light travels in one year, d) the time it takes light to travel around the Earth's orbit
2. Constellations are
a) apparent patterns or designs of stars in the sky , b) physical, related arrangements of stars in the sky
c) still being developed by modern astronomers, d) guide our daily lives
3. The astronomical unit is defined as
a) the time between astronomical observations , b) the mean distance between the Earth and the Sun
c) a unit for measuring the amount of work astronomers do , d) not well defined
4. The observed changing positions of the stars during a night is the result of the
a) tilt of the Earth's axis , b) rotation of the Earth on its axis
c) rotation of the stars on their axes, d) revolution of the Earth around the sun
5. At what time of night would you expect to see a full moon highest in the sky?
a) 6 pm, b) 9 pm, c) 12 midnight, d) 3 am
6. Paris is about 1/4 of the way around Earth from Chicago. On a night when people in Chicago
see a first quarter moon, people in Paris see
a) a new moon, b) a first quarter moon, c) a full moon, d ) a third quarter moon
7. If you observe the moon rising in the east as the sun is setting in the west, then you know that the
phase of the moon must be
a) new, b ) first quarter, c) full, d) third quarter
8. The seasons on Earth occur primarily because the
a) Earth rotates on its axis, b) Earth's axis is tilted with respect to the ecliptic
c) Earth's distance from the sun changes through the year, d) Earth's orbit is an ellipse.
9. The phases of the moon are caused by
a) the moon moving in and out of Earth's shadow
b) different fractions of the moon being illuminated by the sun
c) different degrees of darkness on the moon
d) different amounts of the illuminated half of the moon being visible from Earth
10. What is the altitude of the zenith at 9:00 p.m. on December 21 at a latitude of 40 deg n?
a) 0 deg , b) 40 deg, c) 50 deg, d) 90 deg
11. The apparent path of the sun around the celestial sphere against the background of the stars
during the year is the
a) celestial meridian, b) ecliptic, c) sun's diurnal circle, d) celestial equator
12. Interferometry is used to increase
a) magnifying power, b) resolving power, c) radiation-gathering power, d) all of the above
13. Large telescopes are reflecting rather than refracting because
a) the light gathering power of mirrors is greater than that of lenses
b) lenses more accurately bend light rays to the focus
c) mirrors are easier to support than lenses
d) the Show Me center has an exclusive contract with Pepsi
14. Seeing refers to
a) how far a telescope can see, b) the smearing of an image caused by atmospheric motions
c) the faintest object observable with a telescope, d) the lack of clouds in the atmosphere
15. In the absence of excitation, electrons in an atom tend to be
a) in any allowed orbit , b) in the lowest allowed orbit, c) in the nucleus, d) not in the atom at all
16. When an electron bound in an atom makes a transition from any orbit to a smaller one it:
a) absorbs energy, b) emits energy, c) can absorb or emit energy, d) neither absorbs nor emits
17. Star “a” appears bluish white in color, while star “b” appears reddish in color. This tells you that
a) star a is less luminous than star b, b) star a is hotter than star b,
c) star a is more luminous than star b, d) star a is cooler than star b
18. The frequency at which a star emits the most light depends upon the star's
a) distance from us, b) brightness, c) temperature, d) eccentricity
19. Our bodies ordinarily emit
a) visible light, b) infrared light, c) ultraviolet light, d) radio waves
20. Which type of electromagnetic waves travel faster
a) ultraviolet, b) visible, c) infrared, d) radio
21. The celestial equivalent of longitude is
a) declination, b) the horizon, c) precession, d) right ascension
22. The line which divides the celestial sphere into northern and southern hemispheres is the
a) ecliptic, b) celestial equator, c) meridian, d) horizon
23. On the first day of Spring, the Sun is at the
a) solstice, b) equinox, c) nadir, d) zenith
24. The Moon appears to have an angular size of 1/2 degree. If the Moon were half as far away, what
would be its new angular size if angular size  1/distance?
a) 1/2 degree, b) 1/3 degree, c) 1/4 degree, d) 1 degree
25. If the Earth were inclined more on its axis than it currently is, what would be the consequences?
a) more drastic seasons, b) a longer year, c) more global warming, d) no solstices or equinoxes
26. Given the equation FG = GMm/d2 , if two objects suddenly become separated by half their distance,
what happens to the gravitation force between them
a) stays the same, b) increases by a factor of four
c) decreases by a factor of four, d) increases by a factor of two
27. What is the approximate azimuth (az) elevation (el) of a star which is high in the East.
a) az= 180o, el= 90o b) az= 90o, el= 60o c) az= 270o, el=60o d) az=0o, el=10o
28. When looking down upon the Earth from the North Celestial Pole, in what direction does it rotate?
a) counter clockwise, b) clockwise, c) cannot determine, d) does not appear to rotate
29. At anyone given time, how much of the Moon is illuminated by the Sun?
a) 1/2, b) all, c) 1/4, d) depends on its phase
30. As objects follow their diurnal motion they rise in the East, arc over the South and set in the West.
When do objects have the largest elevation above the horizon?
a) when at the Zenith, b) when at the Right Ascension mark,
c) When near the North Celestial Pole, d) when on the meridian
31. What was one of the hardest thing about the planets motion for the geocentric model of the solar
system to explain.
a) the daily motion of rising in the east and setting the west
b) the number of years it took for the planets to circle the Sun
c) the number of moons the planets had
d) their retrograde motion
32. Newton's second law of motion states F = Ma; where F equals the applied force, M is the mass, and a
equals the acceleration. If I have two masses M1 and M2 and I apply the same force to both of them but M 1
accelerates three times faster than M2. What can I say about M1 compared to M2?
a) M1 is three times more than M2, b) M1 is three times less than M2,
c) M1 is nine times more than M2, d) M1 is nine times less than M2
33. All wave phenomena are characterized by a wavelength, a frequency, and a velocity. They are related
by the equation C = where C is the velocity of the wave,  is the wavelength, and  is the frequency. If
I double the wavelength of a wave, what happens to the frequency
a) it stays the same, b) it increases by 2, c) it decreases by 2, d) it increases by 4
34. 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.
35. If I observe that the North Celestial Pole is on my Northern horizon and the South Celestial Pole is on
my Southern horizon, what must be my location?
a) North Pole, b) South Pole, c) Equator, d) cannot tell from this information alone
36. A planet in a highly elliptical orbit has its greatest speed when
a) it is closest to the Sun, b) when it is furthest from the Sun
c) when the Sun is on the equator, d) when the Sun is on the solstice
37. What do we call the event when the Moon's shadow falls on the Earth's surface
a) lunar eclipse, b) solar eclipse, c) evening solstice, d) shadow time
38. I have determine that the North Celestial Pole is about 35 degrees above the Northern horizon. What
can I say about my location?
a) you are at the equator
b) you are at the North Pole
c) you are at a latitude of 35 degrees north of the equator
d) you are at a latitude of 55 degrees north of the equator
39. What do we call the event when the Sun is located 23.5o north and south of the celestial equator.
a) solstices, b) equinox, c) day of dawns, d) solar eclipses
40. Spectral lines are sometimes referred to as the stars' "fingerprints" because:
a) Then tend to make patterns like the swirls 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
41. (10 points) Sketch a diagram showing how a reflecting and a refracting telescope work. List the
advantages and disadvantages of each kind of telescope.
42. (10 points) Galileo observed the Moon, Sun, and planets Venus, and Jupiter with his new "telescope".
What "new" discoveries did Galileo make concerning these objects and what were their significance.