Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning
Exercise :: Heat Transfer, Refrigeration and Air Conditioning - Section 3
| 36. |
Thermal conductivity of a material may be defined as the |
| A. |
quantity of heat flowing in one second through a slab of the material of area 1 cm2 and thickness 1 cm when its faces differ in temperature by 1° C | | B. |
quantity of heat flowing in one second through one cm of material when opposite faces are maintained at a temperature difference of 1° C | | C. |
heat conducted in unit time across unit area through unit thickness when a temperature difference of unity is maintained between opposite faces | | D. |
all of the above |
Answer: Option D
Explanation:
|
| 37. |
During sensible heating of air, specific humidity remains constant. |
Answer: Option A
Explanation:
|
| 38. |
Air refrigeration cycle is used in |
| A. |
commercial refrigerators | | B. |
domestic refrigerators | | C. |
air-conditioning | | D. |
gas liquefaction |
Answer: Option D
Explanation:
|
| 39. |
Reynolds number is the ratio of |
| A. |
energy transferred by convection to that by conduction | | B. |
kinematic viscosity to thermal diffusivity | | C. |
inertia force to viscous force | | D. |
none of the above |
Answer: Option C
Explanation:
|
| 40. |
The wet bulb depression is zero when relative humidity is |
Answer: Option D
Explanation:
|
