Q3-LR-2

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Pennsylvania State University *

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102

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Mechanical Engineering

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Jan 9, 2024

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1/23/23, 10:36 PM Lesson 3 - Quiz: EGEE 102 (SP23): Energy Conservation for Environmental Protection https://psu.instructure.com/courses/2224925/quizzes/4674334 1/8 Lesson 3 - Quiz Due Jan 28 at 11:59pm Points 25 Questions 13 Available Jan 23 at 12am - Jan 28 at 11:59pm Time Limit 20 Minutes Allowed Attempts 2 Instructions Attempt History Attempt Time Score KEPT Attempt 2 13 minutes 25 out of 25 LATEST Attempt 2 13 minutes 25 out of 25 Attempt 1 10 minutes 22 out of 25 Correct answers will be available on Jan 30 at 12am. Score for this attempt: 25 out of 25 Submitted Jan 23 at 10:36pm This attempt took 13 minutes. Remember that once you start the quiz, you cannot stop the timer. If you leave the quiz, the timer keeps running. You must finish in 20 minutes. Feedback for this Quiz (along with your responses and the correct answers) will be made available after the deadline for this Quiz. 1 / 1 pts Question 1 Which one of the following is true about energy conversion devices? Total Energy Input = Useful Energy Output + Energy Dissipated to the surroundings Total Energy Input = Useful Energy Output
1/23/23, 10:36 PM Lesson 3 - Quiz: EGEE 102 (SP23): Energy Conservation for Environmental Protection https://psu.instructure.com/courses/2224925/quizzes/4674334 2/8 Total Energy Input = Energy Dissipated to the surroundings Total Energy Input = Efficiency X Total Energy Output Total energy = useful energy + waste energy. Refer to section 3.2: Energy Conversion Devices. 1 / 1 pts Question 2 What is the primary form of useful energy output in the case of a car? Mechanical Thermal or Heat Radiation Chemical A car converts chemical energy from the burning of fuel into mechanical energy (rotation of wheels). Refer to section 3.2: Energy Conversion Devices. 1 / 1 pts Question 3 What is the form of useful energy output in the case of a TV? Radiation
1/23/23, 10:36 PM Lesson 3 - Quiz: EGEE 102 (SP23): Energy Conservation for Environmental Protection https://psu.instructure.com/courses/2224925/quizzes/4674334 3/8 Mechanical Thermal or Heat Chemical A TV converts electrical energy into radiation (the pictures that we see). Refer to section 3.2: Energy Conversion Devices. 1 / 1 pts Question 4 Approximately what percentage of input electrical does an incandescent light bulb convert into visible light? less than 10% 30% 85% 90% Most of the electrical energy is lost in the form of heat in an incandescent light bulb. Refer to section 3.3: Energy Efficiencies. 1 / 1 pts Question 5 What is the primary form of useful energy output in the case of a lawn mower?
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1/23/23, 10:36 PM Lesson 3 - Quiz: EGEE 102 (SP23): Energy Conservation for Environmental Protection https://psu.instructure.com/courses/2224925/quizzes/4674334 4/8 Mechanical Thermal or Heat Radiation Chemical A lawn mower converts chemical energy from the burning of fuel into mechanical energy (rotation of blades). Refer to section 3.2: Energy Conversion Devices. 1 / 1 pts Question 6 Energy output must be equal to the input. (1 point) True False First law of thermodynamics states that Energy output must be equal to the input. 2 / 2 pts Question 7 A heat engine converts thermal energy into what type of energy?
1/23/23, 10:36 PM Lesson 3 - Quiz: EGEE 102 (SP23): Energy Conservation for Environmental Protection https://psu.instructure.com/courses/2224925/quizzes/4674334 5/8 Mechanical Thermal Chemical Electrical A heat engine is defined as a device that converts heat energy into mechanical energy. 2 / 2 pts Question 8 Which of the following devices has the highest energy efficiency Home oil furnace Home coal stove Steam boiler in a power plant Electric bulb: fluorescent Home oil furnace-80%; home coal stove-75%; steam boiler in a power plant-90%; electric bulb: fluorescent-60%. 3 / 3 pts Question 9
1/23/23, 10:36 PM Lesson 3 - Quiz: EGEE 102 (SP23): Energy Conservation for Environmental Protection https://psu.instructure.com/courses/2224925/quizzes/4674334 6/8 The following step efficiencies apply to the use of gasoline in a car: Crude production: 93%, Refining 82.3%, Transportation 95.4%, Engine efficiency 21.1%. What is the total efficiency of the process? (Answer units: %, i.e. input 10 not 0.1. Be sure to exclude the % as Canvas does not accept symbols) 15.41 Overall Efficiency of a system is the product of step efficiencies. Please refer to section 3.9: Calculating Overall Efficiency. 3 / 3 pts Question 10 If the energy input of a system is 74 calories and its output is 56 calories, what is the efficiency of the system? (Answer units: %) 75.68 System Efficiency = (useful energy output) / (total energy input) * 100. Please refer to section: Efficiency of Energy Conversion Devices. 3 / 3 pts Question 11 The flame temperature in an automobile engine is 982 °C, and the exhaust is emitted at 53 °C. What is the Carnot efficiency of the engine? (Answer units: %)
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1/23/23, 10:36 PM Lesson 3 - Quiz: EGEE 102 (SP23): Energy Conservation for Environmental Protection https://psu.instructure.com/courses/2224925/quizzes/4674334 7/8 74.02 Use Carnot efficiency formula and temperatures in Kelvin. Please refer to section 3.7: The Carnot Efficiency. 3 / 3 pts Question 12 The flame temperature in an automobile engine is 1,319 °F, and the exhaust is emitted at 151 °F. What is the Carnot efficiency of the engine? (Answer with units of %. i.e. 30 not 0.3. you do not need to provide the %) 65.67 Use the Carnot efficiency formula and temperatures in Kelvin. Please refer to section covering The Carnot Efficiency. 3 / 3 pts Question 13 The useful output from a heat engine is 238 cal. The energy that is wasted is 4,084 J. What is the Carnot efficiency of the engine? (Answer with units of %. i.e. 30 not 0.3. you do not need to provide the %) 19.6
1/23/23, 10:36 PM Lesson 3 - Quiz: EGEE 102 (SP23): Energy Conservation for Environmental Protection https://psu.instructure.com/courses/2224925/quizzes/4674334 8/8 Efficiency = ((useful energy output) / (useful energy output + waste energy output))*100. Note: Use units consistently. Please refer the section of the Efficiency of Energy Conversion Devices. Quiz Score: 25 out of 25