Download –1– AST104 Sp2006: EXAM 1 Multiple Choice Questions: Mark the

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AST104 Sp2006: EXAM 1
c. travel faster than X-rays from the galaxy
d. cannot be detected with any telescopes
Multiple Choice Questions: Mark the best
e. a and d.
answer choice on the bubble form. Read
all answer choices before making selection. 5. If light takes about 10−5 years to reach Earth
(No credit given when multiple answers from the Sun, the distance to the Sun is about
are marked.)
a. 0.1 AU
1. The nearest star to Earth is
b. 10 AU
a. outside the Galaxy
c. 10−5 light years
b. at a distance of 1 AU
d. 105 light years
c. Proxima Centuari
e. none of the above
d. Venus
e. Polaris, the north star
2. Which is the smallest?
a. distance between the Earth and Sun
b. distance between Mercury and the Sun
c. diameter of the Galaxy
d. diameter of the Sun
e. 1 AU
3. 104 + 103 equals
a. 107
b. 1100
c. 10100
d. 1012
e. 11000
6. When are the celestial equator and the ecliptic closest on the sky?
a. winter solstice and summer solstice
b. vernal equinox and autumnal equinox
c. they coincide at all times
d. at noon each day of the year
e. at midnight each day of the year
7. Which is true about seasons?
a. When it is winter in the northern hemisphere, it is winter in the southern hemisphere.
b. there would be no seasons if Earth’s spin
axis were not tilted from the its orbit axis
c. there would be no seasons if Earth’s spin
axis were tilted 90 degrees from its orbit axis.
d. a and b
e. b and c
4. If we observe a galaxy known to be 106 light
years from Earth, radio waves we detect from it 8. If you stand at latitude of 62 degrees North,
what angle would you measure between the northa. were produced 1 million years ago
ern horizon and the North Celestial Pole?
b. were produced by intelligent life
a. 62 degrees
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b. 5 degrees
a. the same brightness as
c. 90 degrees
b. 105 times fainter than
d. 23.5 degrees
c. 2.5 times fainter than
e. 28 degrees
d. 2.5 times brighter than
9. If you stand at latitude of 28 degrees North,
e. 105 times brighter than
what angle would you measure between the north13. The 26,000 year precession cycle of the Earth’s
ern horizon and the Zenith?
spin axis implies that
a. 62 degrees
a. Polaris will not always be the star currently nearest to the North Celestial Pole.
b. 5 degrees
c. 90 degrees
d. 23.5 degrees
b. the average length of a day will dramatically change 13,000 years from now
c. the Zodiacal constellation corresponding
to the Sun’s position on the sky for Feb 28, 2006
10. The point in Mercury’s orbit at which it is will be different from that on Feb 28, 15006.
farthest from the sun is called the
d. Newton’s theory of gravity is wrong since
a. aphelion
it cannot explain any precession.
e. 28 degrees
b. perihelion
c. heliocenter
e. a and c
14. A third quarter moon rises at about
d. apogee
a. sunrise
e. relativity point
b. noon
11. Of the following, which always occurs about
6 months from the last day of summer?
a. a lunar eclipse
b. winter solstice
c. summer solstice
d. autumnal equinox
e. vernal equinox
12. Star A has an apparent magnitude =−5 and
star B has an apparent magnitude =−4. Star A
appears approximately −−−−− Star B.
c. 3 pm
d. sunset
e. midnight
15. The moon has an observed angular diameter
of 0.5 degrees. If the moon were 6 times closer,
what would its observed angular diameter be?
a. 3 degrees
b. 30 degrees
c. 12 degrees
d. 1/12 degrees
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e. 0.5 degrees
16. Lunar eclipses occur
a. when the sun, Earth and moon are along
the line of nodes AND the moon is at new moon.
b. when the sun, Earth and moon are along
the line of nodes AND the moon is at full moon.
c. about 4 times per year.
d. a and c
e. b and c
17. Observers on Earth in the umbra of the
moon’s shadow
a. are unable to see a total solar eclipse.
b. are in the path of totality during a total
solar eclipse.
c. are also in the penumbra.
d. never see an annular eclipse
e. do not experience seasons.
18. The observed phases of Earth’s moon
20. For which of the following does the Earth’s
atmosphere NOT play an important role?
a. the reddish hue of the sunset
b. the reddish hue of the moon during a
lunar eclipse
c. the reason many telescopes are placed at
high altitudes
d. chromatic aberration
e. the blue sky
21. Copernicus’ model of the universe:
a. did not include elliptical orbits
b. included precession of Earth’s spin axis
c. included all presently known planets
d. did not have any epicycles
e. placed the Earth at the center
22. Which is inconsistent with Newton’s laws?
a. a golf ball and bowling ball dropped from
the same height take the same time to land.
a. are based on the sidereal period
b. the Ptolomeic model of the solar system
b. are based on the synodic period
c. the elliptical orbits of planets
c. were not observed before Galileo
d. the phases of Venus observed by Galileo
d. a and c
e. the motion of a tennis ball during a match
e. b and c
23. −−−− used the data of −−−− to first show
that Mars moves on a primarily elliptical orbit
around the Sun.
19. About 6 weeks after a solar eclipse we see
a. another solar eclipse
b. a new moon
c. a first quarter moon
d. a full moon
e. a third quarter moon
a. Kepler, Brahe
b. Newton, Brahe
c. Kepler, Galileo
d. Brahe, Ptolemy
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e. Einstein, Aristarchus
27. The circular orbit speed of the moon around
Earth has the form vcirc = (GM/r)1/2 . What is
24. Who would say that “a force is required to
most correct about this equation?
keep any body moving at a constant velocity”?
a. it is inconsistent with Kepler’s laws
a. Newton
b. r is the radius of the Earth and M is the
b. Einstein
mass of the moon
c. Aristotle
c. r is the distance from Earth’s center to
d. Galileo
the moon’s center and M is the mass of Earth
e. Milankovitch
d. r is the radius of the Earth and M is the
mass of the Earth
25. If it takes 3 years for a planet to make 1/3
an orbit around a star, then its average distance
e. r is the distance from Earth’s center to
from the star is most nearly
the moon’s center and M is the mass of the moon
a. 2 AU
b. 3 AU
c. 4.3 AU
28. The speed a planet needs to transition from
an elliptical orbit to an open orbit is always
a. larger than the orbit speed when compared at the same location
d. 8.5 AU
b. larger than the orbit speed when the
e. 16 AU
planet is closest to the star but smaller when
26. Which is correct about the relation between the planet is farthest from the star
Einstein’s and Newton’s theories?
c. smaller than the orbit speed everywhere
a. Special relativity explains deviations from
d. smaller than the orbit speed when the
Newton’s laws for very large velocities and Gen- planet is closest to the star but larger when the
eral Relativity explains deviations from Newton’s planet is farthest from the star
laws for strong gravity
e. larger for a smaller mass planet.
b. Einstein’s theories are completely incon29. Suppose a star were placed 10 times closer
sistent with Newton’s theories
from Earth than it is presently. The star would
c. Einstein’s theories cannot accommodate appear −−−− times as bright, with a gravitaKepler’s laws whereas Newton’s theory can
tional force −−−− times as strong, and the angud. The deflection of light from distant stars lar size would be −−−− times as large.
by the sun’s gravity is consistent with Newton’s
theory but inconsistent with Einstein’s theory
e. Einstein’s theories were needed to explain
the observed phases of Venus
a. 10, 10, 10
b. 10, 100, 10
c. 100, 10, 10
d. 100, 100, 10
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e. 100, 100, 100
30 (Note: Post-exam corrections in boldface
below)
Which is true about mass and weight?
b. resolving power, magnifying power, stability of mounting and positioning accuracy
c. light gathering power, magnifying power,
stability of mounting and positioning accuracy
d. light gathering power, resolving power,
a. two people of equal mass have the same
magnifying power
weight when measured on the same planet
e. it depends on the wavelength
b. if object A weighs 100 kg on Earth and
object B weighs 100 kg on the Moon, it is possi- 33. A telescope with a 2 meter objective mirror
diameter filtered to view light at 450nm gathble that the objects have the same mass.
ers −−−− times the light, and resolves objects of
b. if object A weighs 100 kg m/s2 on
the angular diameter when compared to a
Earth and object B weighs 100 kg m/s2 on −−−−
1 meter telescope with the same filter.
the Moon, it is possible that the objects
have the same mass
a. 1, 1/2
c. your mass is the same on Earth and Mars
but your weight would differ.
d. your weight is the same when measured
on Earth and Mars but your mass would differ.
e. a,b, and c.
e. a and c
31. If the Moon’s mass were halved and its
distance quadrupled, the gravitational force between Earth and Moon would be
a. 1/32 of its present value
b. 1/16 of its present value
c. 1/4 of its present value
d. 1/2 of its present value
e. equal to its present value
b. 2, 1/25
c. 4, 3/4
d. 2, 3/4
e. 4, 1/2
34. X-rays have longer wavelengths than −−−−− ?
a. Gamma-rays
b. Infrared radiation
c. Ultra-violet radiation
d. visible radiation
e. radio waves
35. Which best describes the tidal force?
a. It is a centripetal (center pulling) force
due to rapid rotation
b. It is a centrifugal (outward flinging) force
32. In addition to lens quality, which are MOST
important for the effectiveness of an optical tele- due to rapid rotation
scope?
c. It is a force induced by orbital revolution
a. light-gathering power, resolving power,
d. It results from the differential gravitastability of mounting and positioning accuracy
tional force acting on different parts of a body.
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e. It results from a repulsive rather than
b.
attractive force.
moon
36. The Chandra X-ray telescope is placed up
in space orbiting around Earth because
they occur at first and third quarter
c. they occur during a lunar eclipse
d. they are inconsistent with Einstein’s thea. Hospital and industrial X-ray machines ory of gravity
interfere with observations near Earth’s surface
e. b and d
b. X-rays are absorbed by the Earth’s atmosphere
True or False:
c. X-rays are reflected by Earth’s surface
d. Telescopes are easier to repair in space.
40. Radio telescopes are ineffective from the
ground and must be placed in orbit.
41. If Earth had no moon, there would be no
e. The best mountain top sites are already
tides.
crowded with optical telescopes.
42. Radio waves travel at the speed of sound
37. Which is WORST for observing a faint source
and X-rays travel at the speed of light.
and has the WORST chromatic aberration?
43. If the moon orbited at 1/4 it present disa. a 1 meter diameter reflecting telescope
tance, we would never see annular solar eclipses.
b. a 1 meter diameter refracting telescope
44. If unknown object A has a larger observed
c. a 4 meter diameter refracting telescope
angular diameter than unknown object B, then
we know that object B is farther away.
d. a 4 meter diameter reflecting telescope
e. cannot determine with knowing the dis- 45. Professional ground based optical telescopes
are refracting telescopes because reflecting teletance to the source
scopes suffer from chromatic aberration.
38. Source A emits X-rays at a wavelength 3
times that from source B. The ratio of the speed 46. Unlike Newton’s theory of gravity, Kepler’s
of propagation of X-rays from A compared to Laws were based only on observations, and could
not explain deviations from elliptical orbits.
that of B is:
a. 9
b. 1/9
c. 1/3
d. 1
e. 3
39. What is true about neap tides?
47. An object in an elliptical orbit experiences
both force and acceleration.
48. An object in a circular orbit experiences
acceleration but no force.
49. Observations of the light from stars behind
the sun during a solar eclipse played an important role in verifying Einstein’s theory of gravity.
50. 400 nm light has a frequency 5/4 times that
a. they occur at new and first quarter moon of 500 nm light
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Answers
28.A
1.B
29.D
2.D
3.E
4.A
5.C
6.B
7.B
8.A
9.C
10.A
11.E
12.D
13.E
14.E
15.A
16.B
17.B
18.B
19.D
20.D
21.A
22.B
23.A
24.C
25.C
26.A
27.C
30.E (all answers but D were given credit
due to the typos on the original exam.)
31.A
32.A
33.E
34.A
35.D
36.B
37.B
38.D
39.B
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40. F
41. F
42. F
43. T
44. F
45. F
46. T
47. T
48. F
49. T
50. T