mechanical engineering MCQs – Page 152

Practise multiple-choice questions from mechanical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

mechanical engineering Mcqs

1. compressors gas turbines and jet engines 2. theory of machines 3. nuclear power plants 4. engineering materials 5. strength of materials mechanical engineering 6. thermodynamics 7. heat transfer 8. i c engines 9. steam boilers engines nozzles and turbines 10. engineering mechanics 11. fluid mechanics mechanical engineering 12. production technology 13. machine design 14. hydraulic machines 15. workshop technology 16. refrigeration and air conditioning

3021. Thermal conductivity of glass-wool varies from sample to sample because of variation in ________________ ?
0

A. structure

B. porosity

C. density

D. all of the above

E. composition

3022. Thermal conductivity of air at room temperature in kcal/m hr C is of the order of__________________?
0

A. 0.5

B. 0.02

C. 0.002

D. 0.1

E. 0.01

3023. Thermal conductivity of water in general with rise in temperature ____________________?
0

A. increases

B. decreases

C. remains constant

D. may increase or decrease depending on temperature

E. none of the above

3024. The amount of heat flow through a body by conduction is_______________?
0

A. all of the above

B. dependent upon the material of the body

C. directly proportional to the temperature difference on the two faces of the body

D. directly proportional to the surface area of the body

E. inversely proportional to the thickness of the body

3025. In counter flow heat exchangers_________________?
0

A. both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state

B. both the fluids at inlet are in their hottest state

C. both the fluids .at exit are in their hottest state

D. one fluid is in hottest state and other in coldest state at inlet

E. any combination is possible depending on design of heat exchanger

3026. Thermal conductivity of a material may be defined as the________________?
0

A. heat conducted in unit time across unit area through unit thickness when a temperature difference of unity is maintained between opposite faces

B. quantity of heat flowing in one second through a slab of the material of area one cm square, thickness 1 cm when its faces differ in temperature by 1C

C. quantity of heat flowing in one second through one cm cube of material when opposite faces ^re maintained at a temperature difference of 1C

D. all of the above

E. none of the above

3027. Thermal diffusivity is ____________________?
0

A. useful in case of heat transfer by radiation

B. a dimensionless parameter

C. a physical property of the material

D. used as mathematical model

E. function of temperature

3028. Heat flows from one body to other when they have_________________?
0

A. different heat contents

B. different temperatures