MCQOPTIONS
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MCQOPTIONS
This section includes 9 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. |
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 | |
| 2. |
All the following statements are correct, except |
| A. | Nucleate boiling gets promoted on a smooth surface |
| B. | In subcooled heating, the temperature of the heating surface is more than the boiling point of the liquid |
| C. | Film boiling region is usually avoided in commercial equipment |
| D. | There occurs transition from nucleate to film boiling burn-out point on the boiling curve |
| Answer» B. In subcooled heating, the temperature of the heating surface is more than the boiling point of the liquid | |
| 3. |
Consider the above problem, find the boiling heat transfer coefficient |
| A. | 5330 W/m<sup>2</sup> K |
| B. | 6330 W/m<sup>2</sup> K |
| C. | 7330 W/m<sup>2</sup> K |
| D. | 8330 W/m<sup>2</sup> K |
| Answer» E. | |
| 4. |
An electric wire of 1.25 mm diameter and 250 mm long is laid horizontally and submerged in water at 7 bar. The wire has an applied voltage of 2.2 V and carries a current of 130 amperes. If the surface of the wire is maintained at 200 degree Celsius, make calculations for the heat flux |
| A. | 0.0915 * 10 <sup>6</sup> W/m<sup>2</sup> |
| B. | 0.1915 * 10 <sup>6</sup> W/m<sup>2</sup> |
| C. | 0.2915 * 10 <sup>6</sup> W/m<sup>2</sup> |
| D. | 0.3915 * 10 <sup>6</sup> W/m<sup>2</sup> |
| Answer» D. 0.3915 * 10 <sup>6</sup> W/m<sup>2</sup> | |
| 5. |
Spherical bubbles of 3 mm diameter are observed in the bulk fluid boiling of water at standard atmospheric pressure. Assuming pure water vapor in the bubble and vapor pressure equal to 101.325 k N/m2, calculate the temperature of the vapor |
| A. | 100.217 degree Celsius |
| B. | 200.217 degree Celsius |
| C. | 300.217 degree Celsius |
| D. | 400.217 degree Celsius |
| Answer» B. 200.217 degree Celsius | |
| 6. |
What is the value of surface fluid constant for water-brass combination? |
| A. | 0.004 |
| B. | 0.005 |
| C. | 0.006 |
| D. | 0.007 |
| Answer» D. 0.007 | |
| 7. |
What is the value of surface fluid constant for water-copper combination? |
| A. | 0.010 |
| B. | 0.011 |
| C. | 0.012 |
| D. | 0.013 |
| Answer» E. | |
| 8. |
The bubble diameter has been expressed by Fritz as |
| A. | D <sub>b </sub>= C <sub>d</sub> [2 /g (p <sub>f </sub> p<sub> g</sub>)]<sub> </sub><sup>1/2</sup> |
| B. | D <sub>b </sub>= C <sub>d</sub> [2 /g (p <sub>f </sub> p<sub> g</sub>)]<sub> </sub><sup>3/2</sup> |
| C. | D <sub>b </sub>= C <sub>d</sub> [2 /g (p <sub>f </sub> p<sub> g</sub>)]<sub> </sub><sup>5/2</sup> |
| D. | D <sub>b </sub>= C <sub>d</sub> [2 /g (p <sub>f </sub> p<sub> g</sub>)]<sub> </sub><sup>7/2</sup> |
| Answer» B. D <sub>b </sub>= C <sub>d</sub> [2 /g (p <sub>f </sub> p<sub> g</sub>)]<sub> </sub><sup>3/2</sup> | |
| 9. |
Reynolds number is replaced by a modulus significant of the agitation of the fluid particles in nucleate boiling. Such a dimensionless modulus is defined by the relation |
| A. | Re <sub>b </sub>= 2 D <sub>b </sub>G <sub>b</sub>/ <sub>f</sub> |
| B. | Re <sub>b </sub>= D <sub>b </sub>G <sub>b</sub>/ <sub>f</sub> |
| C. | Re <sub>b </sub>= D <sub>b </sub>G <sub>b</sub>/ <sub>f</sub> |
| D. | Re <sub>b </sub>= 3 D <sub>b </sub>G <sub>b</sub>/ <sub>f</sub><sup></sup> |
| Answer» C. Re <sub>b </sub>= D <sub>b </sub>G <sub>b</sub>/ <sub>f</sub> | |