MCQOPTIONS
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MCQOPTIONS
This section includes 62 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Transfer knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
For laminar film condensation on a vertical plate, the velocity distribution at a distance δ from the top edge is given by |
| A. | p g (δ y – y/2)/σ |
| B. | p g (δ y – y²)/σ |
| C. | p g (δ y – y²/2)/σ |
| D. | p g (δ – y²/2)/σ |
| Answer» D. p g (δ – y²/2)/σ | |
| 52. |
In spite of large heat transfer coefficient in boiling liquids, fins are used advantageously when the entire surface is exposed to |
| A. | Film boiling |
| B. | Transition boiling |
| C. | Nucleate boiling |
| D. | All modes of boiling |
| Answer» E. | |
| 53. |
Milk spills over when it is boiled in an open vessel. The boiling of milk at this instant is referred to as |
| A. | Interface evaporation |
| B. | Sub-cooled boiling |
| C. | Film boiling |
| D. | Saturated nucleate boiling |
| Answer» C. Film boiling | |
| 54. |
Identify the wrong statement with respect to boiling heat transfer? |
| A. | The steam boilers employing natural convection have steam raised through pool boiling |
| B. | Boiling occurs when a heated surface is exposed to a liquid and maintained at a temperature lower than the saturation temperature of the liquid |
| C. | Leiden-frost effect refers to the phenomenon of stable film boiling |
| D. | The nucleation boiling is characterized by the formation of bubbles at the nucleation sites and the resulting liquid agitation |
| Answer» C. Leiden-frost effect refers to the phenomenon of stable film boiling | |
| 55. |
A condenser is to be designed to condense 225.0 kg of steam per hour at a pressure of 0.15 bar. A square array of 400 tubes, each of 6 mm in diameter, is available for the task. If the tube surface temperature is to be maintained at 26 degree Celsius, make calculations for the length of the tube |
| A. | 4.353 m |
| B. | 3.353 m |
| C. | 2.353 m |
| D. | 1.353 m |
| Answer» E. | |
| 56. |
In condensation over a vertical surface, the value of convection coefficient varies as |
| A. | k^0.25 |
| B. | k^0.33 |
| C. | k^0.75 |
| D. | k^-0.5 |
| Answer» B. k^0.33 | |
| 57. |
Natural convection heat transfer coefficients over surface of a vertical pipe and a vertical flat plate for same height. What is/are the possible reasons for this?(i) Same height(ii) Both vertical(iii) Same fluid(iv) Same fluid flow patternSelect the correct answer |
| A. | 4 |
| B. | 1 and 2 |
| C. | 1 |
| D. | 3 and 4 |
| Answer» E. | |
| 58. |
The boiling process has wide-spread applications in(i) Production of steam in nuclear and steam power plants for generation and for industrial processes and space heating(ii) Absorption of heat in refrigeration and air-conditioning systems(iii) Concentration, dehydration and drying of foods and materialsIdentify the correct statements |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 1, 2 and 3 |
| D. | 1 and 3 |
| Answer» D. 1 and 3 | |
| 59. |
Maximum heat transfer rate in a modern boiler is about |
| A. | 2 * 10⁵ W/m² |
| B. | 3 * 10⁵ W/m² |
| C. | 4 * 10⁵ W/m² |
| D. | 5 * 10⁵ W/m² |
| Answer» B. 3 * 10⁵ W/m² | |
| 60. |
Boiling refers to a change from the |
| A. | Solid to a liquid phase |
| B. | Vapor to a liquid phase |
| C. | Liquid to a solid phase |
| D. | Liquid to a vapor phase |
| Answer» E. | |
| 61. |
In which type of boiling the fluid motion is induced by external means? |
| A. | Pool |
| B. | Local |
| C. | Forced convection |
| D. | Subcooled |
| Answer» D. Subcooled | |
| 62. |
Which type of boiling occurs in steam boilers employing natural convection? |
| A. | Forced convection |
| B. | Pool |
| C. | Local |
| D. | Saturated |
| Answer» C. Local | |