Assignment One on Astronomy II - Fall 2009 | ASTR 1020, Assignments of Astronomy

Download Assignment One on Astronomy II - Fall 2009 | ASTR 1020 and more Assignments Astronomy in PDF only on Docsity! Astronomy II (ASTR-1020) — Homework 1 Due: 27 January 2009 The answers of this multiple choice homework are to be indicated on a Scantron sheet Form # 822 N-E (which you are to buy at the bookstore) with a No. 2 pencil. Don’t forget to write your name and the Homework No. (e.g., 1) on the Scantron sheet. You are to turn in this Scantron at the beginning of class on the date indicated above. There are 20 questions on this homework assignment. Useful Constants G = 6.673 × 10−11 m3/s2/kg g = 9.80 m/s2 c = 3.00 × 105 km/s h = 6.626 × 10−34 J s k = 1.38 × 10−23 J/K H◦ = 50 km/sec/Mpc Mmoon = 7.35 × 1022 kg M = 1.99 × 1030 kg M⊕ = 5.98 × 1024 kg R⊕ = 6.38 × 106 m R = 6.96 × 108 m T = 5800 K 1 AU = 1.50 × 1011 m L = 3.90 × 1026 W e = 1.60 × 10−19 C σ = 5.67 × 10−8 W/m2/K4 me = 9.11 × 1031 kg mp = 1.67 × 10−27 kg 1 ly = 9.46 × 1015 m 1 pc = 3.09 × 1016 m 1 km = 103 m 1 hr = 3600 s 1 mi = 5280 ft 1 mi = 1.609 km 1 day = 24 hrs 1 yr = 365.24 days 1 Å = 10−10 m 1 nm = 10−9 m 1. The theory of relativity is a theory because a) Einstein said so. b) its model was the simplest. c) its equations are known by all scientists. d) it has been validated through repeated experiments. e) force is equal to mass times acceleration. 2. Which of the following is not part of the scientific method? a) A hypothesis is made, which is an educated guess as to how something works. b) The hypothesis is debated by scientists, and if debated successfully, becomes a theory. c) The hypothesis is tested through repeated experimentation and/or observations. d) If the hypothesis passes these experiments/observations, it becomes a theory. e) None of these are part of the scientific method. 3. The length of the Earth’s semimajor axis is called the a) Ångstrom b) astronomical unit c) eccentricity d) parsec e) light year 4. If one knew the actual (linear) size of an object and measured the angular size that the object makes on the sky, which of the following formulae would you use to compute the distance to the object? a) rp = a(1 − e) b) d = 206265D/α c) d = θr d) E = mc2 e) F = ma 1 13. Which of the following best describes hydrostatic equilibrium? a) The higher the temperature, the higher the pressure. b) The higher the temperature, the lower the pressure. c) The weight on a layer in a gaseous body is balanced by the internal pressure of that layer. d) The weight on a layer in a gaseous body is balanced by the temperature of that layer. e) None of these are correct. 14. Energy flow via individual particle motions in an object is known as a) radiation transport b) convection c) conduction d) advection e) Bob 15. Which of the following is not a conservation law used in determining nuclear reactions? a) Mass-energy must be conserved. b) Charge must be conserved. c) Baryon number must be conserved. d) Lepton number must be conserved. e) All of these are used. 16. How many hydrogen nuclei are fused into one helium nucleus in the proton-proton chain? a) 1 b) 2 c) 4 d) 8 e) 16 17. Main sequence stars are burning hydrogen into helium through thermonuclear reactions in their cores. In the high-mass main sequence stars, the dominant reaction process is a) proton-proton chain b) CNO cycle c) HCO chain d) HCN cycle e) hydrogen cycle 4 18. Of the following reaction chains, which is not part of the proton-proton chain? a) 12C + 1H −→ 13N + γ b) 3He + 3He −→ 4He + 1H + 1H c) 1H + 1H −→ 2H + e+ + ν d) 1H + 2H −→ 3He + γ e) All of the above reactions are part of the proton-proton chain. 19. Determining the internal structure of the Sun through photospheric sound waves is called a) geology b) seismology c) helioseismology d) topology e) wavology 20. We only detect 1/3 the number of neutrinos that theory predicts from the proton-proton reaction chain occurring at the center of the Sun. This peculiarity is known as the a) CNO problem b) p-p problem c) solar neutrino problem d) CNO cycle e) none of these 5