Question

4. Efficiency of an engine running between 40 0C and - 20 0C

a. 10%

b. Not a possible engine

c. 150%

d. 19%

5. A copper pipe [ α = 1.7 * 10-5 / 0C] is 30 m long at 23 0C. What is the change in length of the pipe when a steam of 90 0C pass through it.

a. 30.1 m

b. 30.4 m

c. 0.034 m

d. 0.301 m

6. Assuming an emissivity, e = 0.2, and an area of approximately 3.3 m2, find the amount of thermal energy radiated by the body in 60 minutes if the surface temperature is 40.0 0C.

a. 4.27 MJ

b. 2.45 MJ

c. 3.56 MJ

d. 1.29 MJ

7. The figure shown depicts a thick metal container with two compartments.Compartment A is full of a hot gas, while compartment B is full of a cold gas. What is the primary mode of heat transfer in this system?

c. Conduction

d. Convection

e. Radiation

f. Convection and Radiation

8. Which of the following is a characteristic of an isochoric process?

a. ΔU=0

b. W=0

c. ΔQ=0

d. ΔV=0

e. ΔP=0

Answer 1