| 1. The Astronomical Unit (A.U.) is 1.50x1011m; this is the mean radius of the Earth's orbit around the Sun. Calculate the travel-time for neutrinos to reach the Earth given that their velocity is 3x108m/s (i.e. the speed of light). About 8.33 minutes |
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2. a) Using the graph to the left, determine the velocity of 20MeV solar protons. About 0.2c or 6.00x107m/s b) What is the travel-time of these protons from the Sun to the Earth? 41.6 minutes 3. a) Using the graph to the left, determine the velocity of 80MeV solar protons. 4. A typical solar proton event usually lasts several hours. Based on your calculations in questions 2 and 3, what might one conclude concerning the period of greatest danger to unprotected astronauts in Earth orbit. What factors might mitigate this conclusion? |
| At first glance one might assume that the beginning of the event poses the greatest danger because it delivers the highest energy particles. However the particle density within the proton stream is not uniform, but rather peaks at some lower energy. At or near this peak the energy absorbed per unit time is greatest and the radiation danger is largest.
5. Intense solar proton events are usually associated with large solar flares. Is it possible for the proton event to begin (i.e. would protons begin arriving at the Earth) before the solar flare is seen? Why or why not? 6. The maximum recommended absorbed dose is 5.0 mSv·a-1 (less for children and expectant moms). At Guarapari Beach, Brazil radioactive sand produces a background of 800 mSv·a-1. How many days could one stay at the beach before exceeding their maximum recommenced dose? 7. The maximum recommended absorbed dose is 5.0 mSv·a-1 (less for children and expectant moms). At Kerala Beach, India radioactive sand produces a background of 35 mSv·a-1. How many weeks could one stay at the beach before exceeding their maximum recommenced dose? 8) The maximum recommended absorbed dose is 5.0 mSv·a-1 (less for children and expectant moms). The permanently evacuated City of Pripyat, (near Chernobyl) Ukraine, has been contaminated with a fallout which produces a background of 5.0 mSv·a-1. How many weeks could one live there before exceeding the maximum recommenced dose? |
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ASSESSMENTThe chart that follows identifies four levels of achievement for assessing students' communication of information and ideas. Levels 1 and 2 describe performance that is approaching the standard for the grade; level 3 describes the standard for the grade; and level 4 describes performance that is above the standard. In numerical terms, all four levels are at passing level for the grade. Level 1 corresponds to a mark of 50%-59%; level 2, 60%-69%; level 3, 70%-79%; and level 4, 80%-100% . Student performance that is not approaching or is significantly below the standard would receive a failing grade. |
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Understanding of Basic Concepts
The student: |
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Level 1
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Level 2
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Level 3
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Level 4
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| demonstrates limited understanding of natural sources of particle radiation by solving assignment problems with limited accuracy | demonstrates some understanding of natural sources of particle radiation by solving assignment problems some accuracy | demonstrates considerable understanding of natural sources of particle radiation by solving assignment problems with general accuracy | demonstrates thorough understanding of natural sources of particle radiation by solving assignment problems with a high degree of accuracy |
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Communication of Information and Ideas
The student: |
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Level 1
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Level 2
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Level 3
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Level 4
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| uses scientific terminology, symbols, conventions, and SI units with limited accuracy and effectiveness | uses scientific terminology, symbols, conventions, and SI units with some accuracy and effectiveness | uses scientific terminology, symbols, conventions, and SI units with considerable accuracy and effectiveness | uses scientific terminology, symbols, conventions, and SI units with a high degree of accuracy and effectiveness |