# Astro 201: Fall 1997 Tests

What follows are the actual fall 97 tests. These are not formatted for html, sorry. Extra character are "TeX" markup commands.

\centerline{\bf Astro 201 --- Test 1} \noindent For the multiple choice questions, circle the most correct answer. \vskip 0.3in \pointbegin The formula $P^2 = a^3$ is an expression of \spoint Newton's second law \spoint Kepler's first law \spoint Kepler's second law \spoint Kepler's third law \point At what time is a first-quarter moon overhead? \spoint 12 noon \spoint 6 p.m. \spoint 12 midnight \spoint 6 a.m. \point The daily rotation of the earth has what consequence? \spoint The sun moves along the ecliptic about $1^\circ$ a day. \spoint The moon shows phases. \spoint Time exposures of the night sky show star trails. \spoint In May, the sun is really in Aries, not Taurus like the astrology columns all say. \point What is $2\times 10^6$ multiplied by $10^{-3}$? \spoint $2 \times 10^{-3}$ \spoint $2 \times 10^{3}$ \spoint $2 \times 10^9$ \spoint ${{1}\over{2}} \times 10^{-3}$ \vfill \eject \point A young, hip civilization on the planet Bebop has two cities almost directly north and south of each other. Vertical sticks placed at both cities show that the sun's angle is 10$^\circ$ different between the two cities, which are 1000 km apart. What is the circumference of planet Bebop? \spoint 360 km \spoint 3,600 km \spoint 36,000 km \spoint 360,000 km \point The name for the average sun-to-earth distance is \spoint a parsec. \spoint an astronomical unit. \spoint a light year. \spoint a year. \point The sun's path (ecliptic) and the celestial equator cross at \spoint the equinoxes. \spoint the zodiac. \spoint the nexus. \spoint the precession. \point On June 21, the summer solstice, you are vacationing on a cruise ship in the Pacific ocean. The Captain tells you that the ship is located on the Tropic of Cancer. (It is summer in the northern hemisphere, and the Tropic of Cancer is the northern tropic.) That noon, you can expect the sun to pass \spoint 23.4 degrees north of the southern horizon. \spoint 23.4 degrees north of the zenith. \spoint 23.4 degrees south of the zenith. \spoint directly overhead. \vfill \eject \point What did Galileo {\it not} see? \spoint Mountains on the earth's moon. \spoint Uranus's moons Titania and Oberon. \spoint Jupiter's 4 largest moons. \spoint The phases of Venus. \point Let's suppose the force that the sun exerts on Mars is exactly $10^{22}$ Newtons. What would the force be if Mars were twice as far away? \spoint $0.25 \times 10^{22}$ N. \spoint $0.5 \times 10^{22}$ N. \spoint $2.0 \times 10^{22}$ N. \spoint $4.0 \times 10^{22}$ N. \point Retrograde motion is exhibited \spoint by inner planets. \spoint by the moon. \spoint by outer planets. \spoint during eclipses. \point To have a solar eclipse, the sun, moon, and earth are in this order: \spoint moon-sun-earth \spoint sun-earth-moon \spoint sun-moon-earth \spoint earth-sun-moon \point What is one of the reasons the sun does not keep mean solar time?'' \spoint The earth spins at different speeds during different parts of the year. \spoint Don't be silly, the sun doesn't even have a watch. \spoint Because of earth's 23.4 degree tilt the sun's motion does not project uniformly on the celestial equator. \spoint The earth's orbit is elliptical and therefore its orbital speed varies slightly. \point Which astronomer of antiquity measured the size of the earth? \spoint Eratosthenes \spoint Aristarchus \spoint Ptolemy \spoint Copernicus \point Which astronomer of antiquity made elaborate models of an earth-centered universe? \spoint Aristarchus \spoint Ptolemy \spoint Copernicus \spoint Tycho Brahe \point Which astronomer of antiquity first applied a telescope to astronomical observation? \spoint Ptolemy \spoint Copernicus \spoint Tycho Brahe \spoint Galileo Galilei \point The formula $F=ma$ is \spoint Kepler's third law. \spoint Newton's first law. \spoint Newton's second law. \spoint a formula used by Galileo. \point Seasons are caused by the earth's orbital motion and \spoint tropics and circles. \spoint earth's axial tilt. \spoint a variable sun. \spoint precession of the equinoxes. \point Where on earth do you have to be in order to see the south celestial pole directly overhead? \spoint North pole \spoint Tropic of Cancer \spoint Equator \spoint South Pole \point When is the next leap year? (Do not use the Julian calendar.) \spoint 1998 \spoint 1999 \spoint 2000 \spoint 2004 \vskip 0.4in \noindent One to three-sentence answers: \point Why isn't there a lunar eclipse every full moon and a solar eclipse every new moon? \vskip 1.5in \point What are degrees, arcminutes, and arcseconds (and how many of which fit into what)? \vskip 2.0in \eject \noindent Sketches: \point Sketch an ellipse below. Label {\it at least} four parts important for the geometry of an ellipse. \vskip 2.0in \point Sketch an outer planet (Mars, for example) and its orbit(s) in two different cosmological models. On the left sketch Mars's orbit(s) as envisioned by Ptolemy, on the right as envisioned by Copernicus. \vskip 2.5in \point Make a sketch illustrating why we have seasons. \vskip 2.0in \eject \end %----------------------------------------------- TEST 2 \centerline{\bf Astro 201 --- Test 2} % equations \hrule \line{$P^2=a^3$ \hfil $F= {{Gm_1 m_2}\over{r^2}}$ \hfil $c=\lambda f$} \line{$\lambda_{\rm measured}/\lambda_{\rm true} = 1 + {v\over c}$ \hfil ${\Delta \lambda \over \lambda} = {v \over c}$ \hfil $d=vt$} \hrule \vskip 0.1in \noindent For multiple choice questions, circle the most correct letter. \pointbegin An astronomer takes a high resolution spectrum of a nearby star and finds that a spectral line normally seen at 5000 \AA\ appears instead at 5005 \AA . This star is \spoint coming toward us. \spoint going away from us. \point If the speed of light is $3 \times 10^5$ km/s, the velocity of the star in the previous question is \spoint 3 km/s. \spoint 30 km/s. \spoint 300 km/s. \spoint 500 km/s. \spoint 3000 km/s. \point Plate tectonics is important in shaping the surface of \spoint Earth \qquad (b) Venus \qquad (c) Moon \qquad (d) Mars \point Hot-spot volcanism created truly gargantuan mountains on \spoint Earth \qquad (b) Venus \qquad (c) Moon \qquad (d) Mars \point The oldest surface'' award goes to \spoint Earth \qquad (b) Venus \qquad (c) Moon \qquad (d) Mars \point The largest greenhouse effect'' award goes to \spoint Earth \qquad (b) Venus \qquad (c) Moon \qquad (d) Mars \point In the absence of perturbations from the gravity of planets, do comets such as Halley's or Hale-Bopp travel on elliptical orbits? \spoint yes \qquad (b) no \point Mercury's orbital period is very close to 1/4 that of earth. Does that imply that Mercury is located at 1/4 A.U.? \spoint yes \qquad (b) no \eject \point After a sun-drenched day Joe Beachcomber watches a crystalline tropical sunset and notices (1) there are neap tides, and (2) he doesn't see any moon in the sky. The phase of the moon is \spoint new \spoint first quarter \spoint full \spoint last quarter \point Which is {\it not} a point of difference between terrestrial and jovian planets? \spoint distance from the sun \spoint orbital plane \spoint size of atmosphere \spoint total mass \point The planets' paths in the sky stay quite close to \spoint the celestial equator \spoint the ecliptic \spoint the line of nodes \spoint the vernal equinox \point The fact that the plane of the moon's orbit is much closer to the ecliptic than to the earth's equatorial plane argues most strongly against which of these lunar formation scenarios? \spoint fission \spoint cocreation \spoint capture \spoint collision \point The fact that the moon's density and isotopic composition closely resembles the mantle layers of earth favors which lunar formation scenario? \spoint cocreation \spoint capture \spoint collision \eject \point Which method for making an atmosphere is almost certainly not important, at least for Venus and the earth? \spoint Early accretion of icy bodies \spoint Solar nebula \spoint Solar wind \spoint Late comet and asteroid impacts \point Which structural layer of earth is liquid? \spoint inner core \spoint outer core \spoint mantle \spoint crust \point Radar is nifty because information on the following is available, even through clouds: \spoint distance and angular size \spoint a unique spectral signature of the composition \spoint all your favorite radio stations \spoint distance and velocity \point Would Jupiter return a bright radar echo? \spoint yes \qquad (b) no \point If interstellar miners removed half of the mass of the moon, by what factor would the moon-earth gravitational force change? \spoint 1/4 \qquad (b) 1/2 \qquad (c) no change \qquad (d) 2 \point Laplace's original nebular hypothesis'' for the formation of the solar system had a difficult time {\it starting} the gravitational accretion process by which planets form. Today's version of this theory incorporates what feature that bridges the gap between no clumping of matter and clumps large enough to have noticeable gravity? \spoint very massive gas molecules \spoint mini black holes \spoint sticky dust particles \spoint comets and asteroids \point By counting craters we know that lunar \undertext{\qquad\qquad} are older. \spoint maria \qquad (b) highlands \vskip 0.2in \hrule \vskip 0.2in \centerline{\bf Longer Questions} \vskip 0.2in \point Sketch the geometry of the orbit of Mars, labeling at least 3 geometrical features and indicating the position of the sun. It is OK to exaggerate the eccentricity of the orbit to show the parts more clearly. \vskip 1.2in \point Why is CO$_2$ missing from Earth's atmosphere? \vskip 1.2in \point Why is H$_2$O missing from Venus's atmosphere? \vskip 1.2in \point List these in the correct order, shortest wavelength first: visible light, ultraviolet, infrared, microwave, gamma rays, radio, X-rays. \vskip 1.2in \point What causes the {\it aurora borealis} (and {\it aurora australis})? \vskip 1.2in \eject \end %------------------------------------------------------------ TEST 3 \centerline{\bf Astro 201 --- Test 3} % equations \hrule \line{$P^2=a^3$ \hfil $F= {{Gm_1 m_2}\over{r^2}}$ \hfil $c=\lambda f$} \line{$\lambda_{\rm measured}/\lambda_{\rm true} = 1 + {v\over c}$ \hfil ${\Delta \lambda \over \lambda} = {v \over c}$ \hfil $m-M=5{\rm log} d - 5$} \line{$v=Hd$ \hfil $E=mc^2$ \hfil $c=3\times 10^5\ {\rm km/s}$ } \line{$d=1/p$ \hfil $v_{esc}^2 = {{2GM}\over{R}}$ \hfil $\Omega_0 = 2q_0$} \hrule \vskip 0.1in \noindent For multiple choice questions, circle the most correct letter. \pointbegin A Joule is the amount of energy a 1-Watt light bulb gives off in one second (the standard units for the meter-kilogram-second system of units that we have been using). How much energy would be produced by the total conversion of 1 kg of material into energy? (For your information, the sun converts this much mass to energy in less than a billionth of a second!) \spoint $9\times 10^{16}$ Joules \spoint $9\times 10^{13}$ Joules \spoint $9\times 10^{10}$ Joules \spoint $3\times 10^5$ Joules \point How distant is a star that has an astronomical parallax of 1/20th of an arcsecond? \spoint 1/2 pc. \spoint 20 pc. \spoint 200 pc. \spoint 50 pc. \point Open cluster NGC 6791 has a distance modulus $m-M=10$ magnitudes. Therefore, at, say, spectral type G, the stars in NGC 6791 are $100\times 100 = 10000$ times dimmer than a G star at 10 parsecs. Using either the inverse square law or the distance modulus formula, what is the distance to NGC 6791? \spoint 100000 pc. \spoint 100 pc. \spoint 1000 pc. \spoint 10000 pc. % break page here \eject \point If interstellar miners removed half of the mass of the moon, by what factor would the moon-earth gravitational force change? \spoint 1/4 \qquad (b) 1/2 \qquad (c) no change \qquad (d) 2 \point At sunset, a moon that is overhead is in what phase? \spoint new \spoint first quarter \spoint full \spoint last quarter \point The part of the sun that we normally see is called the \spoint atmosphere. \spoint chromosphere. \spoint photosphere. \spoint corona. \point A {\it complete} magnetic solar cycle takes \spoint 5.5 years. \spoint 11 years. \spoint 22 years. \spoint 44 years. \point The sun gets its energy from \spoint core hydrogen fusion. \spoint shell hydrogen fusion. \spoint core helium fusion. \spoint latent heat. \point Consider a cold gas cloud that collapses under its own gravity. By rare coincidence, it has no net spin at all. Will this cloud collapse to a disk shape? \spoint yes. \spoint no. \eject \point An H II region usually appears red in color because \spoint interstellar dust both extincts and reddens light. \spoint the red H$\alpha$ line from recombining hydrogen is very strong. \spoint blue light is scattered from dust clouds, while red light gets through unattenuated. \spoint it is very cool. \point Which could {\it not} be plotted on the $x$ axis of the H-R diagram? \spoint color \spoint spectral type \spoint magnitude \spoint temperature \point Which could {\it not} be plotted on the $y$ axis of the H-R diagram? \spoint absolute magnitude \spoint luminosity \spoint apparent magnitude \spoint radius \point Which of the following is about the size of the earth? \spoint a black hole from a 20 $M_\odot$ star. \spoint a neutron star. \spoint a white dwarf. \spoint a pulsar. \point The element iron came from \spoint the Big Bang. \spoint fusion in stars like the sun. \spoint fusion in massive stars. \spoint dust and gas in the Milky Way. \eject \point The element hydrogen came from \spoint the Big Bang. \spoint fusion in stars like the sun. \spoint fusion in massive stars. \spoint dust and gas in the Milky Way. \point Cepheid variable stars are important distance indicators because (1) they are supergiants and thus visible for many Mpc, well into the realm of galaxies, and (2) \spoint measurement of the apparent magnitude gives the pulsation period of the star. \spoint measurement of the period of pulsation gives the size of the star. \spoint measurement of the period of pulsation gives the apparent magnitude of the star. \spoint measurement of the period of pulsation gives the absolute magnitude of the star. %--------- disk/spheroid \vskip 0.1in \noindent For each of the next 5 questions, choose either (a) disk, or (b) spheroid, and write a'' or b'' next to the number. \point \undertext{\qquad} Where am I likely to find globular clusters? \point \undertext{\qquad} Where am I likely to find H II regions? \point \undertext{\qquad} Which appears yellow to red in color, if I see it from a distance? \point \undertext{\qquad} In which do I need to worry about interstellar extinction? \point \undertext{\qquad} Where am I likely to find open clusters? %--------------- \point The spiral arms of a galaxy appear blue because of \spoint the presence of interstellar dust clouds. \spoint the presence of many H II regions. \spoint the presence of many globular clusters. \spoint the presence of young stars. \eject \point Which galaxy type is basically all spheroid? \spoint Barred spiral. \spoint Spiral. \spoint Irregular. \spoint Elliptical. \point If $H_0=50$ km/s/Mpc, what is the approximate distance of a galaxy observed to have a redshift of 5000 km/s? \spoint 250 Mpc \spoint 100 Mpc \spoint 25 Mpc \spoint 10 Mpc \point If the universe has less than the critical density of matter, we live in \spoint an open universe. \spoint a closed universe. \vskip 0.1in \centerline{\bf Short Answer} \vskip 0.1in \point List these in the correct order, shortest wavelength first: visible light, ultraviolet, infrared, microwave, gamma rays, radio, X-rays. \vskip 0.4in \point List the spectral types, hottest first. \vskip 0.4in \point Regarding planetary nebulae: What is the mass of the star from which the P.N. formed? What does the central star become after a few tens of thousands of years? \vskip 1.0in \vfill \eject \point Regarding supernovae: What is the mass of the star that caused the S.N.? What possible stellar remnants are left after the explosion? \vskip 1.2in \point Describe the reason why the sun will eventually leave the main sequence, and how the location of fusion changes as it climbs'' the red giant branch. \vskip 1.2in \point Write the formula, due to Hubble, that describes the expansion of the universe. \vskip 0.4in \point Tell how we can have (1) a universe with no center and (2) every galaxy receeding from {\it the Milky Way} as if we {\it were} the center of the expansion. \vskip 1.5in \centerline{ \bf Slide Identifications} \vskip 0.1in \settabs=7\columns \+ Choose from the following list:\cr \+ (a) spiral galaxy (unbarred) &&& (e) dark cloud \cr \+ (b) barred spiral galaxy &&& (f) H II region \cr \+ (c) irregular galaxy &&& (g) reflection nebula \cr \+ (d) elliptical galaxy &&& (h) Bok globule \cr \point Object 1: \undertext{\qquad} \point Object 2: \undertext{\qquad} \point Object 3: \undertext{\qquad} \point Object 4: \undertext{\qquad} \point Object 5: \undertext{\qquad} \eject \end