Concept explainers
In 1993, the U.S. government instituted a requirement that all room air conditioners sold in the United States must have an energy efficiency ratio (EER) of 10 or higher. The EER is defined as the ratio of the cooling capacity of the air conditioner, measured in British thermal units per hour, or Btu/h, to its electrical power requirement in watts. (a) Convert the EER of 10.0 to dimensionless form, using the conversion 1 Btu = 1 055 J. (b) What is the appropriate name for this dimensionless quantity? (c) In the 1970s, it was common to find room air conditioners with EERs of 5 or lower. State how the operating costs compare for 10 000-Btu/h air conditioners with EERs of 5.00 and 10.0. Assume each air conditioner operates for 1 500 h during the summer in a city where electricity costs 17.0¢ per kWh.
Want to see the full answer?
Check out a sample textbook solutionChapter 22 Solutions
Bundle: Physics for Scientists and Engineers with Modern Physics, Loose-leaf Version, 9th + WebAssign Printed Access Card, Multi-Term
Additional Science Textbook Solutions
Conceptual Physical Science Explorations
Conceptual Physical Science (6th Edition)
Life in the Universe (4th Edition)
University Physics (14th Edition)
- The average life expectancy in Japan is 81 years. What is this time in SI units?arrow_forwardAnswer the following by filling the blank: During a bout with the flu, an 80-kg person ran a fever of 39 oC. Consider that the specific heat of any human body is 3470 J/kg K, how much energy does the body need to burn to reach the fever temperature? The answer (in fundamental SI unit) is ___________ (type the numeric value only, dont use scientific notation)arrow_forward- Ro.. v 12 B IU ev Av ... 3. Rank the following quantities in order from the largest to the smallest: (a) 22g, (b) 0.333kg, (c) 3.3x10 mgarrow_forward
- a chemist is doing some measurements with a thermometer that is accurate to 1 degree k and a pressure gauge that is accurate to 2 bars. Using the equation for the ideal gas law, V=C T/P, where C is a constant and V is volume, T is temperature in Kelvin and P is pressure in bars, how far off on volume(Leave C in the problem and ignore it) can he be assuming max error on each measurement assuming he measure 13 bars and 340 degrees K?arrow_forwardThe solar panels are placed in an optimal position such that they receive a solar power of 1186kWh/m^2 per year1. The average solar cell has an efficiency of 20% and an average household in the Netherlands uses 2990kWh of electricity per year. The average solar panel has dimensions of 165x99cm. How many solar panels do you need?arrow_forwardWhat is the correct number of significant figures for a final answer that uses all of the following given information: 5 solar farms each have an installed capacity of 4.50 MW, an average solar-to-electric efficiency of 17%, and are in a location with an annual average solar radiation of 6.024 kWh/m^2/day (the same as Berkeley, CA)?arrow_forward
- The volume of an automobile tire is 2.5x10^-2m^3. The pressure of the air in the tire is 3.3 atm and the temperature is 25C°. What is the mass of air in grams? The mean molecular mass of air is 29g. Calculate to 2 decimals.arrow_forwardA physical chemist measures the temperature inside a vacuum chamber. Here is the result. T=-75.3 degrees celsius Convert to SI units. Round your answer to decimal place.arrow_forwardB9arrow_forward
- Our classroom was kept at 25.0°C during your experiment, so v is predicted to be 346 m/s. One group of students measured V=343 m/s. What is the percentage error of their measurement? Don't enter the 1% sign in your answer, just the number in front of the "%" sign. Your Answer: Answerarrow_forwardA hot water heater in a residential home runs for an average of 3.3 hours per day with a heat energy input of 4.3 kW. What would be the annual cost for hot water in this home using an electric hot water heater if the cost of electricity is $0.16/kWh [round your final answer to zero decimal places]?arrow_forwardDuring a bout with the flu an 80-kg person ran a fever of 39 oC. Consider that the specific heat of any human body is 3470 J/kg K, how much energy does the body need to burn to reach the fever temperature? The answer (in fundamental SI unit) is ___________ (type the numeric value only, dont use scientific notation)arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegeUniversity Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University