PHY 1033 Fall 2011 Exam #4 In class (1 hr. 40 min. ending 4:40 pm sharp) G.G. Ihas Dec. 6 You are allowed to consult one 8.5”x11” sheet of paper with anything written on it in your own hand, and to use a calculator, ruler, and pencils or pens. Number your answer to each question clearly, answering them in numerical order in a “Blue/Green Book” test form. If you answer an extra credit question, put it right below/beside the question it is with and label it “E‐x”, where x=number of question. To receive extra credit, you must answer the question associated with it correctly and the extra credit question exactly correctly. Do not violate the UF honor code. Answers without the required justification or explanations will be counted wrong, even if they are correct. You may quietly ask me any question after raising your hand, but my answers will only clarify the exam questions. Good luck! c(light) = 3x108 m/s c(sound in room air) = 341 m/s f(microwave oven) = 2450 MHz m(neutron)=939 Mev=1.675x10‐27 kg h = 6.6x10‐34 J/Hz Q(electron) = 1.6x10‐19 C m(proton)=938 Mev=1.673x10‐27 kg m(electron)=0.511 Mev=9.11x10‐31 kg 1.
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Give an accurate definition of Absolute Zero. What is its temperature in Celsius? Extra credit (1 pt.): What is the property of matter which tells us it is always in motion, even at absolute zero? We used Charles’ Law in determining absolute zero in the lab. State Charles’ Law. Extra credit (1 pt.): Give the equation for the ideal gas law. Name 3 temperature scales and their values at absolute zero. Extra credit (1 pt.): Name one more, and give its value at absolute zero. Define an inertial reference frame. Extra credit (1 pt.): Give an example of a non‐inertial reference frame. Stephanie observes 2 events which are 1.5 seconds apart. Bryan is traveling by her at a speed of 0.95c. Does Bryan see the two events 1.5 sec, more than 1.5 sec, or less than 1.5 sec apart? Explain. For extra credit (2 pt.), calculate the time interval between the events that Bryan experiences. Jacqueline observes 2 events which are 1.5 meters apart. Jacob is traveling by her at a speed of 0.75c. Does Jacob see the two events 1.5m, more 1,5m, or less than 1.5m apart? Explain. For extra credit (2 pt.), calculate how far apart in space Jacob sees the events. What measurement can one twin do to detect that he will be a different age than his twin when one travels to Mars and back while the other stays on Earth? Note: the answer is not use a clock. Extra credit (1 pt.): Which twin is younger after the experiment? If an electron/anti‐electron pair at rest annihilate, what frequency photon is produced? Extra credit (1 pt.): In what part of the E‐M spectrum is this photon? State either one basic fact or principle upon which the special theory of relativity is based. Extra credit (1 pt.): Who postulated this first (not Einstein)? State the other basic fact or principle upon which the special theory of relativity is based. . Extra credit (1 pt.): Who postulated this first (not Einstein)? What do I measure for your gamma (γ) if you are traveling at 0.6c directly away from me? You travel in the x direction at the γ of problem #11. You pass a meter stick which lies along the x axis, parallel to your direction of travel. How long does the meter stick look to you? Extra credit (1 pt.): In this motion you pass another meter stick which lies on the z‐axis. How long do you think it is? Who invented the first artificial ice machine? Extra credit (1 pt.): In what city did he invent it? Is your chair in this classroom an inertial frame of reference? Explain your answer. A 1040 Hz tuning fork excites what wavelength of sound in room air? Extra credit (1 pt.): What length column of class room air would you need to resonant the fundamental mode of this sound wave? Two tuning forks as in problem #15 are made to oscillate in phase. One is 1.00 m directly in front of you and the other 1.16 m in front of you. What do you hear? Explain, perhaps drawing a picture. How far apart are the hot spots when cooking in a microwave oven (no turn table)? Show your calculation. A standing wave is composed of how many waves doing what? Be specific. Can a photon convert into 2 particles (like an electron‐positron pair), both of which are at rest? Explain. Extra credit (1 pt.): In this process there are 2 kinds of energy involved. Name both of them. The carbon nucleus (6 protons and 6 neutrons) can turn into a nitrogen nucleus (7 protons and 5 neutrons). How much energy is either absorbed or released in the process? Extra credit (1 pt.): Is energy absorbed or released in the process?