Exam 20: Thermal Properties and Processes

A square hole,30 cm on each edge,is cut in the center of a square aluminum plate 1 m on a side.The coefficient of linear expansion of aluminum is 2.4 $\times$ 10^-5/Cº.If the plate is heated 25 ºC above the starting temperature,the area of the hole

Calculate the rate of heat transfer from a 1.5 m $\times$ 1.0 m window frame that is made of aluminum.The thickness of the frame is 1 mm and measures 3 cm from inside to outside.The inside room temperature is 25 ^$\circ$ C and outside temperature is 0 ^$\circ$ C.

The amount of linear expansion of a rod does not depend on

A well-known technique for achieving a very tight fit between two components is to "expand by heating and then cool to shrink fit." For example,an aluminum ring of inner radius 5.98 cm needs to be firmly bonded to a cylindrical shaft of radius 6.00 cm (Measurements are at 20 ^$\circ$ C).Calculate the minimum temperature to which the aluminum ring needs to be heated before it can be slipped over the shaft for fitting. (Coefficient of linear expansion for Al = 24 $\times$ 10^-6/K.)

You are trying to decide what the change in heat loss would be if you put a 100 cm $\times$ 150 cm and 5-mm thick glass window in an outside wall.The thickness of the wall is 15 cm.If the thermal conductivities of the glass and wall are 0.90 W/m·K and 0.15 W/m·K respectively,calculate the difference in heat loss through thermal conductivity with and without the window when the outside temperature is -10 ^$\circ$ C and the inside temperature is 15 ^$\circ$ C.

You are testing thermal conduction through two different materials,A and B,of the same cross-sectional area.Material A is twice as thick as material B,and the thermal conductivity of material A is three times higher than that of material B.What is the thermal resistance of A divided by the thermal resistance of B?

A sheet of metal has a star shaped hole.What happens to the distance,d,when the temperature of the sheet is increased?

Under some conditions,real gases depart from Boyle's law due to

If the absolute temperature of an object is doubled,the rate at which it radiates thermal energy

Mountaineers say that you cannot hardboil an egg on the top of Mount Rainier.This is true because

The critical temperature of any gas is

The triple point of a substance gas is

If a piece of iron is exposed to the sun,its temperature rises until

The gas tank of your car can hold 60 L of gasoline.Do you get more gasoline in terms of the number of moles when you fill your tank when the gasoline is cold or hot? The coefficient of volume expansion for gasoline = 930 $\times$ 10^-6/K and that of steel is 33 $\times$ 10^-6/K.

During the evening the partial pressure of water vapor in the air remains constant.As the temperature decreases,the relative humidity

The coefficient of thermal expansion of water at 20ºC is 0.207 $\times$ 10 ^-3 K ^-1.A thin glass tube contains a 75.0 cm column of water at 20ºC.If the thermal expansion of the glass tube is negligible,by how much does the length of the column of water expand when it is heated to 80ºC?

If the thickness of a uniform wall is doubled,the rate at which heat is conducted through the wall is

A thermo keeps a hot drink hot and a cold drink cold for a long time.Shown below is a cut-away section of a thermo with the important features labeled.The reason for the silvered double-wall vacuum chamber is

A clock pendulum made of aluminum,which has a coefficient of linear expansion of 24 $\times$ 10^-6/K,has a period of exactly 1 s at 20ºC.Before a homeowner leaves town for one week,he turns the thermostat down to 10ºC.When he returns,the clock is

On a day when the temperature outside is 0ºC and the relative humidity outside is 100%,what is the relative humidity inside a house at 20ºC,assuming that the partial pressure of water vapor inside and outside the house is the same? (Use the accompanying table.)