MCQOPTIONS
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MCQOPTIONS
This section includes 12 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Transfer knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The ratio of the moisture-vapour pressure to the saturation value at the same temperature is called __________________ |
| A. | Relative humidity |
| B. | Absolute humidity |
| C. | Humidity |
| D. | Percentage humidity |
| Answer» B. Absolute humidity | |
| 2. |
The vapour pressure of a liquid is always same at a given temperature and pressure and hence does not change for highly porous solids. |
| A. | True |
| B. | False |
| Answer» C. | |
| 3. |
What is the term V in the Kelvin equation? |
| A. | Molar liquid volume |
| B. | Molal liquid volume |
| C. | Mole fraction of liquid |
| D. | Normal liquid volume |
| Answer» B. Molal liquid volume | |
| 4. |
If given the surface tension of water as 73×10-3 N/m and diameter of capillary as 1mm, calculate the ratio of capillary-vapour pressure of water in this solid to the saturation vapour pressure at 25℃. |
| A. | 99.8% |
| B. | 90% |
| C. | 98% |
| D. | 97% |
| Answer» B. 90% | |
| 5. |
What is the term PO in the Kelvin equation given below? |
| A. | PO is the superheated vapour pressure |
| B. | PO is the saturation vapour pressure |
| C. | PO is the sub-cooled vapour pressure |
| D. | PO is the elevated vapour pressure |
| Answer» C. PO is the sub-cooled vapour pressure | |
| 6. |
Which one of the following equation correctly represents the lowering in vapour pressure due to capillaries? |
| A. | PK=PO exp\([\frac{2\sigma v}{d_p RT}] \) |
| B. | PK=PO exp\([-\frac{\sigma v}{d_p RT}] \) |
| C. | PK=PO exp\([-\frac{2\sigma v}{d_p RT}] \) |
| D. | PK=PO exp\([-\frac{2\sigma v}{d_p R}] \) |
| Answer» D. PK=PO exp\([-\frac{2\sigma v}{d_p R}] \) | |
| 7. |
What does the Kelvin equation tell us about? |
| A. | The liquid vapour pressure is less than normal |
| B. | The liquid vapour pressure is very less than normal |
| C. | The liquid vapour pressure is more than normal |
| D. | The liquid vapour pressure is equal to normal |
| Answer» B. The liquid vapour pressure is very less than normal | |
| 8. |
A capillary-porous material may be _______________ |
| A. | Hygroscopic |
| B. | Non-hygroscopic |
| C. | Hydrophobic |
| D. | Hydrophilic |
| Answer» C. Hydrophobic | |
| 9. |
The necessary condition of drying is that it only takes place if the wet material contains ________ moisture than the equilibrium value for its environment. |
| A. | Less |
| B. | More |
| C. | Same amount of |
| D. | Very less amount of |
| Answer» C. Same amount of | |
| 10. |
70 – 90% reduction in thermal energy requirements can be achieved by which one of the following drying methods? |
| A. | Drum drying |
| B. | Airless drying |
| C. | Steam drying |
| D. | Salt drying |
| Answer» C. Steam drying | |
| 11. |
What happens in airless drying? |
| A. | High pressure drying in the chamber |
| B. | Low pressure drying in the chamber |
| C. | High temperature drying |
| D. | Steam is produced by compressing the evaporated water |
| Answer» E. | |
| 12. |
A closed vacuum or high-pressure vessel cannot be applied for which one of the following drying operation? |
| A. | Steam drying |
| B. | Flash drying |
| C. | Furnace drying |
| D. | Drum dryers |
| Answer» B. Flash drying | |