PHYS/ENVS)3070) Practice)Final)Exam)) Fall)2014) 1 Your name ____________________________________ Student ID# ____________________________________ Your signature ____________________________________ INSTRUCTIONS: There are 20 numbered multiple-choice questions on the exam, each worth 5 points. Note: the pages are double sided. The exam is OPEN BOOK and non-cellphone calculators are allowed. NO ADDITIONAL NOTES ARE ALLOWED. When amounts are asked for, use numbers from the textbook unless amounts are given in the problem. Notes:'''_"Mark"your"name"on"the"test"and"the"bubble"sheet"_"Mark"your"ID"on"the"bubble"sheet"_"Marking"answers"on"BOTH"the"bubble"sheet"and"the"exam"booklet"is"recommended"_"At"the"end"of"the"exam,"submit"BOTH"the"bubble"sheet"and"the"exam"booklet"PHYS/ENVS)3070) Practice)Final)Exam)) Fall)2014) 2 Problem 1 [5 pts] In the United States the total energy consumed per year per person is roughly A) 3 GJ B) 10 GJ C) 50 GJ D) 300 GJ E) 2,500 GJ Problem 2 [5 pts] Which of the following is NOT a unit for power: A) horsepower (hp) B) Megawatt (MW) C) TeraWatt-hours per year (TWh/yr) D) kilojoule per day (kJ/day) E) kilowatt-hour (kWh) Problem 3 [5 pts] The energy in fossil fuels that we burn in our cars today represents solar energy that was captured in organic molecules _____ years ago. A) 100,000 B) 500,000 C) 10,000,000 D) 200,000,000 E) 3,000,000,000 Problem 4 [5 pts] Which country has the largest reserves of natural gas? A) People's Republic of China B) United States of America C) Russia D) Saudi Arabia E) CanadaPHYS/ENVS)3070) Practice)Final)Exam)) Fall)2014) 3 Problem 5 [5 pts] A temperature of T = 100 degrees Fahrenheit is the same as ___ degrees Kelvin: A) 38 B) 68 C) 273 D) 311 E) 373 Problem 6 [5 pts] What is the Carnot efficiency of a heat engine that has steam injected into it at 1000 C and exhausted at 450 C? A) 86 % B) 21 % C) 67 % D) 43 % Problem 7 [5 pts] The typical efficiency of a single crystal silicon solar cell is A) 3% B) 7% C) 15% D) 30% E) 60% Problem 8 [5 pts] The Solar Constant is 2 calories/minute/square centimeter. What does it tell you physically? A) Power per area at the surface of the earth. B) Energy per area at the surface of the earth. C) Power per area above the atmosphere of the earth. D) Energy per area above the atmosphere of the earth. E) Energy per area on the surface of the sun.PHYS/ENVS)3070) Practice)Final)Exam)) Fall)2014) 4 Problem 9 [5 pts] If a 50-meter high waterfall has a flow rate of 9000 kg per minute, what is the power in watts in the stream of water as it hits the bottom? A) 9.8 watts B) 210 watts C) 1600 watts D) 73,500 watts E) 132,000 watts Problem 10 [5 pts] A wind of 24 m/s produces __ times as much power per unit area as does an 8 m/s wind. A) 27 B) 9 C) 45 D) 81 Problem 11 [5 pts] The fuel rods in a commercial thermal light water nuclear reactor have in them initially: A) Natural UO2 pellets B) UO2 pellets with the 235U enriched to about 3% C) UO2 pellets with 100% of 235U D) UO2 pellets with 100% of 238U Problem 12 [4 pts] Most of the energy liberated in nuclear fission of U-235 is in the kinetic energy of _____. A) neutrons B) protons C) electrons D) gamma rays E) fission fragmentsPHYS/ENVS)3070) Practice)Final)Exam)) Fall)2014) 5 Problem 13 [5 pts] High temperatures are required in fusion reactors because: A) The high temperature reduces the pressure of the plasma B) The high temperature increases the density of the plasma C) High-temperature nuclei have more collisions per unit time D) The two combining nuclei have opposite charges E) The two combining nuclei are both positively charged Problem 14 [5 pts] Most of the energy released in a DT thermonuclear fusion reaction is carried off by A) ultra-violet radiation B) neutrons C) alpha particles D) gravitational potential energy E) tritium nuclei Problem 15 [5 pts] The primary source of SO2 pollution in the United States is: A) Highway vehicles B) Oil and gas exploration C) Coal-burning power plants D) Landfills E) Agricultural waste Problem 16 [5 pts] Which of the following is not an allowed chemical reaction? A) Cl + O3 ! ClO + O2 B) O2 + NO ! NO2 + O2 C) 2NO ! N2 +O2 D) O3 + NO ! NO2 + O2 E) All of the above are allowedPHYS/ENVS)3070) Practice)Final)Exam)) Fall)2014) 6 Problem 17 [5 pts] How much has the world's temperature changed over the last 100 years? A) Increased by about 0.7 degrees Fahrenheit B) Increased by about 1.4 degrees Fahrenheit C) Increased by about 10 degrees Celsius D) Decreased by about -1.3 degrees Celsius E) Increased by about 274 Kelvin Problem 18 [5 pts] Compared to the pre-industrial situation, current levels of greenhouse gases in Earth's atmosphere lead to an additional solar power input (climate forcing) of 1.6 Watts/m2 (averaged over 24 hours per day). What amount of power does that give globally? [Hint: you may assume Earth to be a perfect sphere with radius r = 6.4 x 106 meters and area 4 π r2.] A) 312 GigaWatts B) 975 MegaWatts C) 100,000 kWh D) 820,000 GigaWatts Problem 19 [5 pts] Which of the following has the largest contribution to the rise in global sea levels? A) Melting ice in Greenland B) Melting ice in Antarctica C) Melting icebergs floating at sea D) Thermal expansion of the sea water Problem 20 [5 pts] Which one of these countries has the largest per capita rate of CO2 emissions into the atmosphere? A) China B) Germany C) USA D)
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