1. A steel tape measure has been calibrated at 25^oC. If the tape measure is used to measure the distance between two surveying stakes when the outside temperature is 15^oC, the measurement will be:

 

a. high

b. low

c. accurate

d. length measure is needed to answer

 

Answer: _____

 

 

2. The coefficient of thermal expansion for iron is 12 x10^-6/C^o. What is the change in length of a 2 meter iron rod when its temperature changes by 100^oC?

 

a. 0.0024 cm

b. 0.24 m

c. 0.0024 m

d. 0.024 m

 

Answer: _____

 

 

3. One end of an iron rod is placed in a fire where the temperature 502^oC, and the other end is kept at a temperature of 26^oC. The rod is 1.2 m long and has a radius of 5 mm. Thermal conductivity of iron is 79 J/(s m C ^o). Find the cross-sectional area of the rod.

 

a. 7.9 m²

b. 7.9 x 10^-5 m²

c. 6.0 x 10^-3 m²

d. 2.5 x 10^-5 m²

 

Answer: _____

 

 

4. One end of an iron rod is placed in a fire where the temperature 502^oC, and the other end is kept at a temperature of 26^oC. The rod is 1.2 m long and has a radius of 5 mm. Thermal conductivity of iron is 79 J/(s m C^o). Ignoring the heat loss along the length of the rod, find the amount of heat conducted from one end of the rod to the other in 5 seconds.

 

a. 1.2 x 10¹ J

b. 1.0 x 10¹ J

c. 8.0 x 10¹ J

d. 6.0 x 10¹ J

 

Answer: _____

 

 

5. Radiant energy is proportional to:

 

a. T

b. T²

c. T³

d. T⁴

 

Answer: _____

 

 

6. ___________________________ cannot take place through vacuum.

 

a. Conduction and convection

b. Convection and radiation

c. Conduction and radiation

d. Conduction, convection, and radiation

 

Answer: _____

 

 

7. What is the outside temperature if 2.50 x 10⁶ J of heat is lost through 4 m² of 3 cm thick glass (k_glass = 0.800 W/(m K) ) in one hour from a house kept at 20^oC?

 

a. 5.50^oC

b. 7.50^oC

c. 9.50^oC

d. 11.5^oC

e. 13.5^oC

 

Answer: _____

 

 

8. An aluminum wire with a thermal conductivity of 205 W/(m K) has a cross-sectional area of 2.88 x 10^-6 m². After 1 hour, the heat transferred down its length is 42.1 J. If the difference in temperature of the ends of the wire is 405 K, what is the length of the wire?

 

a. 176 m

b. 2.66 m

c. 20.4 m

d. 5.68 x 10^-3 m

 

Answer: _____

 

 

9. A steel beam has a length of 25 m on a cold day when the temperature is 0^oC. By what amount does the length of the beam increase on a hot day when T = 40^oC? (a_steel = 1.1 x 10^-5 /C^o)

 

a. 4.4 x 10^-4 m

b. 4.4 x 10^-3 m

c. 1.1 x 10^-2 m

d. 4.4 x 10^-2 m

 

Answer: _____

 

 

10. A glass pane 4 mm thick has an area of 2 m². On a winter day the temperature difference between the inside and the outside surfaces of the pane is 20^oC. What is the rate of heat flow through this window? (Thermal conductivity for glass is 0.80 J/(s m K).)

 

a. 32,000 J/s

b. 8,000 J/s

c. 4,000 J/s

d. 1,000 J/s

 

Answer: _____