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ASTR102 f06 midterm exam

ASTR102 f06 midterm exam - WW1 2’9:2 S In section A...

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Unformatted text preview: WW1 2’9 :2 S In section A answer all questions on scantron form, with a #2 pencil. Each question is worth 2 points. You may assume the following: 1 light year = 9.467x1015 m 1 light minute = 180x108 m 1 light second = 3x103 m 1 parsec = 3.09x1016 m c=3x103m/s _ 3.09x1016 m d p 1 yr = 365.25 days l1/l5= 100 l=L/4*pi/\2 I1/I2 =(100)1/5 P = sigma * TA4 * 4 * Pi * m P: L: ©T44rrlTRQ l = L/(4a'cr2) Q AWL—M r=dm0nmma gm?“ PLEASE PRINT a ll . E . I 'I l) H is more abundant than He in the sun. The ratio, by mass, of HiHe is about: a) 2:1 b) 1:2 65 3:1 d) 1:3 e) 1:1 2) According to astronomers, how old is the solar system? _ a) 10 billion yrs 7b,) 5 billion yrs c) 14 billion yrs d) 1 million yrs e) 10 million yrs 3) The process that powers the sun is fusion of H—>He in the core. in this process energy'is given off. What else is emitted? (a) neutrinos b) neutrons c) electrons d) protons é) deuterium 4) A particular star has a spectrum which shows extremely strong absorption lines due to H. The star is probably of spectral type: a) o b) B c))A d) K e) M J’ 5) The distance to the moon is about 3.8 x 10A8 m. This is about: 8 (SHOW x ,w a) 3.8 x 10A8 l.secs b) 1.3 |.mins [EDLS l.secs gyi ggjztr d) 8.3 |.mins e) 8.3 l.secs 6) What is the hottest part of the sun? fa) core b) corona c) photosphere d) chromosphere e) convection region just below the photosphere \/7) In a certain year, when a maximum # of sunspots were visible, the leading spot in the southern hemisphere had north magnetic polarity. About 11 years later the leading spot in the northern hemisphere will have polarity N @N (£395 0) in between d) no magnetic polarity there wi e no spots on the sun - it's at minimum \/8) The temperature of the surface of the sun's photosphere is about a) 273 K b) 17x106 K 73105 K .6000 K e) 0 °C 9) A certain star has molecular bands in its absorption spectrum due to Titanium dioxide. The star is probably of spectral type a) 0 b) B c) F d) G (QM 10) A certain wave of electromagnetic radiation has a wavelength of about 600 nms. The wave is in which part of the spectrum? . 000033-. a) X-ray b) UV (”EM/Bible d) R e) radio v.00 “20 33m \#/‘ _ (:3 \fll) What is really special about the star, Betelgeuse, in Orion? f) . (K a)\it is a blue giant b) it is a white dwarf fl. ( )it is currently going SNOVA d) it is on the main sequence lama, \ @ it probably already exploded 75““ ‘ - J 12) Two stars, A and B, have apparent magnitudes mA=7 and m3=9.\:\§ Star A appears brighter than star B by a factor of rm; _ if" 2 a: ' C) a) 7/9 b) 9/7 c) 2 d) 2.5 é))6.3 .. “ y g. Q . AW 9, J, ' ~ .2. \/l 3) Roughly how many galaxies are in the Local Group? If: {9 - 92> t B , Q a) 2 .30 (5)1000 d) 10,000 e) 50,000 . to» J 14) The Andromeda galaxy is about 2.2 x 106 light years away from us. in meters this is about , , 1 Wm 1.?X10W 0% a) 9.5x1015 m b) 2.2x106 m ¢)\2.1x1022 m ‘* 1.; " d) 3x108 m e) none of these \/15) A certain star, in a direction perpendicular to the plane of the earth's orbit around the sun, has parallactic angle p"=0.6". The A distance to the star is about i...) . 5,: ” l L6 ”f ' 1. lb a) 5.2x1015 m 3.09x1016 m @154 light years 3.0015410 d) 1.9x1015 m e) none of these ' ‘ . (0 . - i — ammo “’m 16) What spectral type is the sun? a) O b) B c) A @9 e) M 17) What are the most distant objects we can see in the Universe? G), quasars I b) red giant stars c) planets C : >\+(\ d) Cepheid variables e) spiral galaxies 9r 7 W10 {7 Svlo’w 18) What is the frequency of light of wavelength 500 nms? -9 :9- SOCMC x 9,500 Hz b) 3 x 1OA8 Hz c) 3 x 10A8 Hz : 3Xio‘3 z”d))6 x10/\14 Hz e) 1.7 x10A-15 Hz c ‘ 600x10 : (”10qu 19) The metallicity of a star is: a) the % by mass of H in the star b) the % by mass of He in the star c) the % by mass of sodium, and other elements that get positively ionized, in the star d) the % by mass of iron, nickel, brass, copper... all the things we usually think of as 'metals' ~\ 5 @}he % by mass of everything inthe star that is NOT H or He. 20) The solar wind consists of: a) em radn b) neutrons c) He nuclei d) neutrinos @ protons and electrons \/21) The spectrum of a normal star consists of: a) a continuous (rainbow) spectrum b) an absorption spectrum ‘ c an emission spectrum a continuous spectrum overlain with an absorption spectrum / e a continuous spectrum overlain with an emission spectrum 22) What word(s) best describes sunspots: a cool b) dark c) high magnetic fields d) in photosphere @ all the above 23) A star has an angle of parallax 1.5".a How far away is it? db: if: s . , , l .11 5, @1 pc {1 . b) 2 pc c) 0.5 pc d) 2.65 pc e) 5 pc 0%? PC _,,> p Q 24) Star A is‘twice as hot as star B. The radius of A is 3 times that of QA‘ V j; P” B. The ratio of power generated by A compared to B is: T); 2 9TB 2 g , 4 (2 .L’; 5 1' ~ 13:11-. a) l6fb)2144 c) 9 d) 81 e) none of the above LL/AB («gar’l -' HQ (CF)? 4 25) in the SNO neutrino experiment in Ontario, Canada, the medium used to capture neutrinos is: a) ordinary water \b\) oil c) lead @HDO e) deuterium ...
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