MCC PHS 142 M01 Astronomy Homework Ch.6-7 Adj Prof Astronomy: Sam Wormley <firstname.lastname@example.org> Web: edu-observatory.org/eo/mcc.html Background Material Textbook - Read Chapters 6-7 Textbook - http://highered.mcgraw-hill.com/sites/0073512184/student_view0/chapter6/ Textbook - http://highered.mcgraw-hill.com/sites/0073512184/student_view0/chapter7/ (take the Multiple Choice Quiz for for each chapter) Textbook - Glossary, pg G-1 words like: opposition, conjunction Web - http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html Web - http://edu-observatory.org/eo/starcharts.html Web - http://www.asahi-net.or.jp/~zs3t-tk/atlas_85/atlas_85.htm Web - http://mathworld.wolfram.com/Eccentricity.html Web - http://edu-observatory.org/eo/telescopes.html Web - http://www.celestron.com/c3/support3/index.php Web - http://edu-observatory.org/eo/dark.html Web - http://antwrp.gsfc.nasa.gov/apod/archivepix.html Web - http://edu-observatory.org/eo/radio_astronomy.html Homework Problems Note the answers to the odd (Conceptual Questions, Problems and Figure-Based Questions) are in the back of your textbook. It is strongly suggested that you do some of those in every chapter so you have immediate feedback as how well you are understanding the material. There are online multiple choice quizzes for each chapter of your textbook. Goto http://www.mhhe.com/fix then click on Your book Student Edition Choose a chapter Multiple Choice Quiz You are expected to do all of your own homework. Statistical patterns showing copying or collaboration will result in no credit for the homework assignment for all participants involved. The Code of Academic Conduct for Iowa Valley Community College District is found in the Student Handbook. Physical Science classes require the use of mathematics. If you don't know algebra, you sould NOT be taking this class. If you need to review, look at Introduction to Algebra http://www.math.armstrong.edu/MathTutorial/ WolframAlpha is way faster than a scientific calculator. http://www.wolframalpha.com There is little excuse for turning homework in late. You have a whole week between classes to read the chapters and do the homework. Homework one week late - half credit. Two or more weeks late - no credit. Do the homework during the week, not in class! You got homework questions, email me 24/7. email@example.com Even if you don't have a homework question, email me anyway! Problem 1: Determine in what constellation, Venus appears to be on your next Birthday. Note the Right Ascension, in degrees for the first day of each month, is on the back of your planisphere. The declination is that of the ecliptic as planets tend to follow the ecliptic. Problem 2: What is the wavelength of electromagnetic radiation that has a frequency of 3 x 1016 Hz? In what part of the spectrum does this radiation occur? Hint: if you use Figure 6.5 on page 105, look at Appendix 17 on page A-13. One could also use equation (6.2). Problem 3: How close to the Sun would a spacecraft have to go to reach the distance that the flux of solar energy (intensity of heat and light) is 20 times as large as the solar energy flux at the Earth? Hint: Think about this--Newton's inverse square law applies. You could estimate this graphically or you could create and use a formula. Problem 4: Suppose atoms at rest emit visible light with a wavelength of 500 nm. At what wavelength would the light from the atoms be observed if the atoms were moving toward the Earth at a speed of 20,000 km/s? Hint: Would equation 6.3 be useful as an step toward the answer? Problem 5: A 4-meter optical telescope operates at a wavelength of 5 x 10-7 meters. How large would an infrared telescope operating at 10-4 m have to be to have the same resolution as the optical telescope? Hint: You could create an equation equating ratios. Problem 6: An astronomer observes Mars at opposition using a telescope that has an aperture of 50 cm (20 inches) in diameter. The astronomer observes in visible light at a wave length of 500 nanometers (nm). What is the smallest feature the astronomer could resolve assuming no degradation by the Earth's atmosphere. Hint: To do this problem you have to know: o What does it mean that Mars is at opposition? o What is the distance between Earth and Mars when Mars is at opposition? o What is the angular resolution of the astronomer's telescope? Yes you can use equation (6.6) to determine the angular resolution. You must keep track of units and convert them so that the the numerator and denominator are in the same units. o Once you have the angular resolution, either use trig, or the small angle equation (3.1) or (3.2) to determine the the smallest feature the astronomer could resolve. Show all of your work including all units. Problem 7: Use Figure 6.5 to find the wavelength of a radio wave with a frequency of 106 Hz. Hint: Appendix 17 on page A-13. Problem 8: Using your star wheel (planisphere), determine how many hours and minutes the star Sirius is above the horizon. Problem 9: Use Figure 7.4 to find the pressure at an altitude of 20 km. Problem 10: How does the brightness of sunlight at Neptune's distance compare with the brightness at the Earth? Hint: Newton's inverse square law applies. Problem 11: The half-life of an unstable isotope is 10 years. After what length of time would there be less than 1% of the original atoms of the isotope remaining? Hint: There isn't any applicable formula in your textbook, so you should approach this graphically--Virtical axis being percent of atoms left and horizontal axis time in units of ten years.