Module #5 – Unit TestPhysics 1401 Question 1The gauge pressure in your car tires is 2.70✕ 105 N/m2 at a temperature of 35.0°C when you drive it onto a ferry boat to Alaska. What is their gauge pressure later, when their temperature has dropped to -41.0°C? Assume that their volume has not changed.Answer: 1.76 atmQuestion 2Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a total of 10 rubs a distance of 7.50 cm each and with a frictional force averaging 50.0 N, what is the temperature increase? The mass of tissue warmed is only 0.100 kg, mostly in the palms and fingers.Answer: 0.107 °CQuestion 3A certain gasoline engine has an efficiency of 28.0%. What would the hot reservoir temperature be for a Carnot engine having that efficiency, if it operates with a cold reservoir temperature of 180°C? °CAnswer:356.1Question 4Absolute zero on the Celsius temperature scale is –273.15 °C. What is absolute zero on the Fahrenheit temperature scale?Select one:A. –459.67 °F B. –427.67 °FC. –331.67 °FD. –363.67 °FE. –395.67 °FQuestion 5Three thermometers are in the same water bath. After thermal equilibrium is established, it is found that the Celsius thermometer reads 0 °C, the Fahrenheit thermometer reads 12 °F, and the Kelvin thermometer reads 273 K. Which one of the following statements is the most reasonable conclusion?Select one:A. The Fahrenheit thermometer is incorrect. B. The three thermometers are at different temperatures.C. The Celsius thermometer is incorrect.D. The Kelvin thermometer is incorrect.E. All three thermometers are incorrect.Question 6Complete the following statement: Bimetallic strips used as adjustable switches in electric appliances consist of metallic strips that must have differentSelect one:A. mass.B. volume.C. specific heat capacities.D. length.E. expansion coefficients. Question 7The coefficient of linear expansion of steel is 12 × 10–6/C°. A railroad track is made of individual rails of steel 1.0 km in length. By what length would these rails change between a cold day when the temperature is –10 °C and a hot day at 30 °C?Select one:A. 620 cmB. 48 cm C. 24 cmD. 0.62 cmE. 480 cmQuestion 8The units of heat are equivalent to those of which one of the following quantities?Select one:A. temperatureB. force/timeC. work D. powerE. specific heat capacityQuestion 9The specific heat capacity of iron is approximately half that of aluminum. Two balls of equal mass, one made of iron and the other of aluminum, both at 90 °C, are dropped into a thermally insulated jar that contains an equal mass of water at 25 °C. Thermal equilibrium is eventually reached. Which one of the following statements concerning the final temperatures is true?Select one:A. The aluminum ball will reach a higher final temperature than the iron ball.B. The difference in the final temperatures of the balls depends on the initial mass of the water.C. The iron ball will reach a higher final temperature than the aluminum ball.D. The difference in the final temperatures of the balls depends on the initial temperature of the water.E. Both balls will reach the same final temperature. Question 10A beaker of water is placed on a Bunsen burner. As the lower layers of water are heated, they become less dense and rise. This permits cooler layers to move downward and be heated. Eventually, the water boils. Which method(s) of heat transfer is (are) primarily responsible for boiling the sample?Select one:A. radiationB. conductionC. convectionD. both conduction and radiationE. both conduction and convection Question 11The sun continuously radiates energy into space in all directions. Some of the sun's energy is intercepted by the earth. The average temperature of the surface of the earth remains a little above 300 K. Why doesn't the earth's temperature rise as it intercepts the sun's energy?Select one:A. The heat is carried away from the earth by convection currents.B. The energy only raises the temperature of the upper atmosphere and never reaches the surface.C. The earth reflects the sun's light.D. The earth radiates an amount of energy into space equal to the amount it receives.E. The thermal conductivity of the earth is low.Question 12Complete the following statement: The space between the inner walls of a thermos bottle is evacuated to minimize heat transfer bySelect one:A. conduction.B. conduction, convection, and radiation.C. conduction and convection. D. radiation.E. conduction and radiation.Question 13A system containing an ideal gas at a constant pressure of 1.42 × 105 Pa gains 2320 Jof heat. During the process, the internal energy of the system increases by 2540 J. What is the change in volume of the gas?Select one:A. zero m3B. +2.36 × 10–3 m3C. –2.36 × 10–3 m3D. –1.55 × 10–3 m3 E. +1.55 × 10–3 m3Question 14Which one of the following statements best describes the operation of a heat engine?Select one:A. A heat engine transfers heat from a lower temperature reservoir to a higher temperature reservoir through work performed on the system.B. A heat engine decreases the entropy of the universe by generating an equal amount of heat and work.C. A heat engine performs work and generates an equal amount of heat in a cyclic process.D. A heat engine uses input heat to perform work and rejects excess heat to a lower temperature reservoir. E. A heat engine transfers heat from a higher temperature reservoir to a lower temperature reservoir through work performed on the system.Question 15Which one of the following statements is not a consequence of the second law of thermodynamics?Select one:A. A motor can operate using the atmosphere as a heat reservoir.B. The natural direction of heat flow is from hot to cold.C. Only reversible processes have a zero net entropy change for the universe.D. There is zero net entropy change for the universe in the operation of a real refrigerator. E. The efficiency of any engine is less than 100%.Question 16Which of the following samples exhibits the highest degree of entropy?Select one:A. ammonia vapor B. a block of paraffinC. liquid oxygenD. a block of graphiteE. a diamond
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