Unformatted text preview: Physics 2 C Spring 2009 Quiz 7A Nam e___________________________________ 4 2
Constants s = 5.67x10‐ 8 W/(m 2 K ) , k = 1.38 x10‐ 23 J/K , NA = 6.0x10 3 m olecules /m ole MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A 5.0 kg block of ice is used to cool a styrofoam ice chest with an area of 1.5 m2 . If the styrofoam has a thickness of 3.0 cm and how long will it take for the ice to m elt if the outside tem pera ture is 25o C? (kstyrofoam = 0.029 W/m K, L f (ice) = 334 kJ/kg) A) 6.8 h B) 12.8 h C) 15.3 h D) 5.9 h 1) E) 9.6 h 4 2) A substance has a m elting point of 20°C and a heat of fusion of 3.9 x 10 J/kg. The boiling point is 150°C and the heat of vaporization is 7.8 x 104 J/kg at a pressure of one atm osphere. The specific 2) heats for the solid, liquid, and gaseous phases are 600, 1000, and 400 J/kg ∙ K, respectively. The quantity of heat required to raise the tem pera ture of 3.80 kg of the substance from ‐ 6 °C to 128°C, in kJ, is closest to: A) 620 B) 770 C) 470 D) 560 E) 210 3) A therm om eter flashes the tem pera ture in Celsius and Fahrenheit along with the tim e. If it flashes 25°F, what will the therm om eter flash in Celsius? A) ‐ 3.9 °C B) ‐ 18.1°C C) 13.9°C D) 77°C 3) 4) What is the rm s speed of an m olecule of oxygen at a tem pera ture of 100 o C? M olecular m ass =5.3x10‐ 26 kg. 4) A) 920 m /s B) 376 m /s C) 263 m /s D) 540 m /s E) 450 m /s 5) A quantity of an ideal gas is heated in a rigid container of constant volum e. If the gas is originally at a tem perature of 19°C, at what tem pera ture will the pressure of the gas double from its base value? A) 91°C B) 273°C C) 311°C D) 38°C E) 122°C 5) o 6) A glass of tea has a tem perature of 80 C and a surface area of 200 cm 2 . What is the rate of heat loss by ra diation to the room which is at a tem perature of 22o C. (em issivity =0.93). 6) A) 13.5 W B) 25.2 W C) 8.4 W 1 D) 1.6 W Answer Key Testname: QUIZ 7 1) B 2) A 3) A 4) D 5) C 6) C 2 ...
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- Spring '11
- 20°C, 400 J, 8.4 W, 19°C, Tem pera ture, 376 m