Download PH109, Exploring the Universe, Test #1, Spring, 1999

PH109, Exploring the Universe, Test #1, Spring, 1999
NAME______________________________________
Please indicate the best answer to the following questions on the separate answer sheet
provided. Each question is worth 2 points unless noted otherwise.
1. 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
2. When looking down upon the Earth from the North Celestial Pole, in what direction does it revolve
around the Sun?
a) counter clockwise, b) clockwise, c) cannot determine, d) does not appear to revolve
3. 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
4. The Arctic circle is the region around the Earth's north pole where, during the summer solstice, the
region receives 24 hours of daylight. In degrees of Latitude, how far from the north pole does the Arctic
circle extend?
a) 33.33 degrees, b) 23.5 degrees, c) depends on the season, d) 23.5 radians
5. The tropic of cancer is the imaginary line north of the Equator where it appears the Sun is overhead
during the summer solstice. In degrees of Latitude, how far from the equator in the Tropic of Cancer?
a) 33.33 degrees, b) 23.5 degrees, c) depends on the season, d) 23.5 radians
6. 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
7. Why are there seven days of the week on our current calendars?
a) seven was the only number which was easily divided into the number of months of the year,
b) seven was considered a "magic" number,
c) that was how many celestial objects in the sky moved with respect to other objects,
d) the Roman kingdom of the time had seven regions
8. Why are there 12 months in a year on our current calendar?
a) the year is easily divisible into 12 parts, b) 12 was considered a "magic" number,
c) there are 12 lunar cycles in a year, d) because there are 12 Zodiac signs in the sky
9. I wake up in the middle of nowhere with amnesia. The only thing I can remember is my astronomy
class. I notice at night that the north star appears to be 25 degrees above my northern horizon. What can I
write on the note in the bottle I throw out to sea that will help my rescuers find me?
a) my longitude is 25 degrees, b) my latitude is 25 degrees,
c) my right ascension is 25 degrees, d) my declination is 25 degrees
10. Approximately what is the azimuth (AZ) and elevation (EL) of the planet Venus located 1/3 of the way
up in the southwest?
a) AZ=230o, EL=30o, b) AZ=30o, EL=230o, c) Az=110o, EL=30o, d) AZ=30o, EL=110o
11. Most of the stars in a constellation are
a) born from the same starcloud, b) about the same age,
c) about the same size, d) unrelated
12. I look at the room around me first with my left eye and then with my right eye. I notice a table appears
to shift more than does a desk. Which object is closer
a) table, b) desk, c) cannot tell, d) they are at the same distance
13. Given the same situation as in the question before this one (12). Which object has the greatest
parallax?
a) table, b) desk, c) cannot tell, d) they are at the same distance
14. Why does the climate on Earth undergo seasons?
a) the axis of rotation of the Earth is tipped with respect to the plane of its revolution,
b) the Earth is closer to the Sun in the Summer and further from the Sun in the winter,
c) the Sun gets brighter and dimmer on a 12 monthe cycle,
d) the Earth rotates faster then slower causing the length of the days to change
15. Newton's law of gravity can be expressed as F g = GM1M2/d2 where Fg is the force due to gravity, G is a
constant, M1 and M2 are the mass of the two objects, and d is the distance between the them. If their
distance is increased by a factor of two, what happens to the force between the two masses?
a) increases by a factor of two, b) increases by a factor of four
c) decreases by a factor of two, d) decreases by a factor of four
16. Kepler's third law state that the square of a planets period in years is equal to the cube of its distance
from the sun in astronomical unites, thus P 2 = a3. If the planet Mars is twice as far from the Sun as is the
Earth, how long is a Martian year?
a) one Earth year, b) two Earth years, c) 8 Earth years, d) 10 Earth years.
17. 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
18. 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 four times faster than M2. What can I say about M1 compared to M2?
a) M1 is four times more than M2, b) M1 is four times less than M2,
c) M1 is two times more than M2, d) M1 is two times less than M2
19. 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 frequency of a wave, what happens to the wavelength
a) it stays the same, b) it increases by 2, c) it decreases by 2, d) it increases by 4
20. Wien's law states that the wavelength of peak emission in a black-body emission curve is inversely
related to the temperature and is written as max  1/temperature. If I double the temperature of an object
what happens to the wavelength of maximum emission max?
a) it is reduced by 1/2, b) it is increased by 1/2, c) it is reduced by 1/4, d) it stays the same
21. If I observe two stars and notice the first star is redder than the second star, what can I say about the
two stars?
a) the first star has more Hydrogen, b) the second star has more Hydrogen,
c) the first star is cooler, d) the second star is cooler
22. How can astronomers determine what material distant objects are made of?
a) the spectral they give off is unique to the material,
b) the temperature of the object is related to the type of material,
c) the speed of the object is related to is type of material,
d) its Doppler frequency is related to its material type
23. A police officer is sandwiched between two brick buildings so he can only see you as you pass by in
front of him. If he tries to determine your speed with a radar gun, what will be the result?
a) you will get a ticket,
b) he can only determine your line of site velocity, he measures zero,
c) we will record the spectral signature of your vehicle and track you down,
d) you will go free because radar cannot work near to brick buildings
24. What kind of a telescope uses a magnifying lens in the front end to image distant objects?
a) reflecting, b) refracting, c) X-ray, d) Georgian
25. The ability of a telescope to image faint objects depends on the area of its lens. If I double the size of a
circular telescope, what happens to its ability to image faint objects?
a) remains the same, b) increases by two, c) increases by four, d) increase by five
26. What prevents large ground-based telescope from achieving the same angular resolution as the Hubble
Space Telescope (HST)?
a) they're not as big as HST, b) atmospheric seeing,
c) HST is a reflecting telescope, d) HST can observe 24 hours per day.
27. What kind of spectrum would you expect if you shine a continuous spectrum through a cool gas?
a) continuous, b) emission, c) absorption, d)
28. How many astronomical units are there between the Earth and sun?
a) One, b) Ten, c) One million, d) Six trillion
29. The Moon is growing more full each night. This is called _____.
a) gibbous, b) waxing, c) waning, d) phases
30. Which of the following properties is constant for all types electromagnetic waves?
a) wavelength, b) speed, c) energy, d) frequency
31. 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.
32. What time of day does the first quarter moon rise?
a) noon, b) sunset, c) midnight, d) sunrise
33. What is the brightest planet in the west at sunset this month?
a) Venus, b) Jupiter, c) Mars, d) Vega
34. Local noon corresponds to the time when the Sun is at the
a) zenith, b) meridian, c) nadir, d) ecliptic
35. The point directly over an observer's head is that observer's
a) equator, b) pole, c) zenith, d) node
36. The north-south line that passes directly overhead is the
a) ecliptic, b) meridian, c) horizon, d) azimuth
37. 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
38. The special thing about the North star is that
a) it is located in a constellation which makes a "N" in the sky
b) it is one of the brightest stars in the sky
c) it is deep red in color
d) it is near the north celestial pole
39. 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
40. 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
41. (10 points) Explain why atoms have discreet wavelengths that they emit and absorb photons at.
`
42. (10 points) Kepler's second law states that a line drawn from the sun to a planet sweeps out equal areas
in equal times. Give an example of Kepler's second law and explain with ample detail how Kepler's law is
demonstrated.