Exam 4, PHYS 101-4M 18 November MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

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1 Exam 4, PHYS 101-4M 18 November 2005 Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) If the absolute temperature of a radiator is doubled, by what factor does the radiating power change? A) 16 B) 4 C) 2 D) 8 2) Which temperature scale never gives negative temperatures? A) Fahrenheit B) Celsius C) Kelvin D) all of the above 3) Which has more molecules, a mole of oxygen gas or a mole of nitrogen gas? A) oxygen B) nitrogen C) both the same 4) Ice has a latent heat of fusion of 333,000 J/kg. How much heat is required to melt 0.2 kg of ice? A) 66,600 J B) 16,500 J C) 400 J D) 160 J 5) Water has a higher specific heat than sand. Therefore, during the daytime, breezes blow: A) from the ocean to the beach B) from the beach to the ocean C) either way 6) A container of an ideal gas at 1 atm is compressed to one-third its volume, with the temperature held constant. What is its final pressure? A) 3 atm B) 1 atm C) 9 atm D) 1/3 atm 7) Which two temperature changes are equivalent? A) 1 Ce = 1 K B) 1 K = 1 Fe C) 1 Fe = 1 Ce D) none of the above 8) When a solid melts A) heat energy leaves the substance. B) heat energy enters the substance. C) the temperature of the substance decreases. D) the temperature of the substance increases. 9) An ideal gas occupies 4.0 L at 20eC. What volume will it occupy at 40eC if the pressure remains constant? A) 8.0 L B) 2.0 L C) 43 cm3 D) 4.3 L 10) Two identical cylinders at the same temperature contain the same gas. If A contains three times as much gas as B, which cylinder has the higher pressure? A) Cylinder A B) Cylinder B C) both the same 11) kg of lead (c = 130 J/kgœeC) at 100eC is put into kg of water at 0eC. What is the final temperature of the mixture? The specific heat of water is 4186 J/kgœeC. A) 2eC B) 50eC C) 6.8eC D) 25eC 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 1

2 12) The specific heat of concrete is greater than that of soil. A baseball field (with real soil) and the surrounding parking lot are warmed up during a sunny day. Which warms up more quickly, the field or parking lot? A) baseball field B) parking lot C) both warm up equally fast 13) The three phases of matter can exist together in equilibrium at the A) triple point. B) critical point. C) melting point. D) evaporation point. 14) The average molecular kinetic energy of a gas can be determined by knowing only A) the pressure of the gas. B) the volume of the gas. C) the number of molecules in the gas. D) the temperature of the gas. 15) Two equal-mass liquids, initially at the same temperature, are heated for the same amount of time over the same stove. You measure the temperatures and find that one liquid has a higher temperature than the other. Which liquid has a higher specific heat? A) the hotter one B) the cooler one C) both the same 16) By what primary heat transfer mechanism does the Sun warm the Earth? A) conduction B) convection C) radiation D) all of the above in combination 17) If the pressure acting on an ideal gas at constant temperature is tripled, its volume is A) increased by a factor of two. B) reduced to one-third. C) increased by a factor of three. D) reduced to one-half. 18) Which is the largest unit of temperature: one Celsius degree, one Kelvin degree, or one Fahrenheit degree? A) Celsius degree B) Fahrenheit degree C) Kelvin degree D) both one Celsius and one Kelvin degree E) all of the above 12) 13) 14) 15) 16) 17) 18) 2

3 19) Which of the following best explains why sweating is important to humans in maintaining suitable body temperature? A) The high specific heat of water on the skin absorbs heat from the body. B) Functioning of the sweat glands absorbs energy that otherwise would go into heating the body. C) Evaporation of moisture from the skin extracts heat from the body. D) Moisture on the skin increases thermal conductivity, thereby allowing heat to flow out of the body more effectively. E) None of the above explains the principle on which sweating depends. 20) At what temperature is the average kinetic energy of an atom in helium gas equal to J? The Boltzmann constant is 1.38x10-23 J/K. A) 300 K B) 250 K C) 200 K D) 350 K 21) The number of molecules in one mole of a substance A) is the same for all substances. B) depends on the molecular weight of the substance. C) depends on the atomic weight of the substance. D) depends on the density of the substance. 22) Convection can occur A) only in liquids. B) only in gases. C) in solids, liquids, and gases. D) only in liquids and gases. E) only in solids. 23) A grandfather clock uses a brass pendulum to keep perfect time at room temperature. If the temperature in the room drops by 100 degrees, how will the grandfather clock be affected? A) clock will run slower than usual B) clock will still keep perfect time C) clock will run faster than usual 24) Consider a flat steel plate with a hole through its center as shown in Fig When the plate's temperature is increased, the hole will 19) 20) 21) 22) 23) 24) FIGURE 13-2 A) expand only if it takes up more than half the plate's surface area. B) always contract. C) contract if it takes up less than half the plate's surface area. D) always expand. 3

4 25) By what primary heat transfer mechanism does one end of an iron bar become hot when the other end is placed in a flame? A) forced convection B) natural convection C) radiation D) conduction 25) 26) Two drinking glasses are stuck, one inside the other. How would you get them unstuck? A) Run hot water over them both B) Put hot water in the inner one C) Put cold water in the inner one D) Break the glasses 26) 27) A steel bridge is 1000 m long at -20eC in winter. What is the change in length when the temperature rises to 40eC in summer? (The average coefficient of linear expansion of steel is /Ce.) A) 0.33 m B) 0.55 m C) 0.44 m D) 0.66 m 27) 28) The internal energy of an ideal gas depends on A) its temperature. B) its volume. C) its pressure. D) all of the above 28) 29) 1 kg of water at 80 oc is poured into a bucket that contains 4 kg of water at 20 oc. Find the equilibrium temperature (neglect the influence of the bucket). A) 15 oc B) 32 oc C) -10 oc D) 100 oc 29) 30) A 1 kg block of silver (c=234 J/kg oc) is heated to 90 oc, then dunked in a tub of 1 kg of water (c=4186 J/kg oc) at 10 oc. What is the final equilibrium temperature? A) 14 oc B) 27 oc C) 111 oc D) 52 oc 30) 31) Convert 14eC to K. A) 46 K B) 287 K C) 100 K D) 474 K 31) 32) The heat required to change a substance from the solid to the liquid state is referred to as the A) heat of vaporization. B) heat of freezing. C) heat of melting. D) heat of fusion. 32) 33) If you add some heat to an object, is it possible for the temperature to remain unchanged? A) Yes B) No 33) 34) You are using test A. Fill in the bubble for "A" and write "Test A" next to your name. A) A B) B C) C 34) 4

5 Answer Key Testname: EXAM 4 1) A 2) C 3) C 4) A 5) A 6) A 7) A 8) B 9) A 10) A 11) A 12) A 13) A 14) D 15) B 16) C 17) B 18) D 19) C 20) A 21) A 22) D 23) C 24) D 25) D 26) C 27) D 28) A 29) B 30) A 31) B 32) D 33) A 34) A 5