MCQOPTIONS
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MCQOPTIONS
This section includes 8 Mcqs, each offering curated multiple-choice questions to sharpen your Mass Transfer knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Consider the above problem, find what percent of power is lost by free convection? |
| A. | 19.478% |
| B. | 19.378% |
| C. | 19.278% |
| D. | 19.178% |
| Answer» D. 19.178% | |
| 2. |
Estimate the heat transfer from a 40 W incandescent bulb at 125 degree Celsius to 25 degree Celsius in quiescent air. Approximate the bulb as a 50 mm diameter sphere. The approximate correlation for the convection coefficient is
|
| A. | n Where the different parameters are evaluated at the mean film temperature, and characteristics length is the diameter of the sphere |
| B. | 4.71 W |
| C. | 5.71 W |
| D. | 6.71 W |
| E. | 7.71 W |
| Answer» E. 7.71 W | |
| 3. |
Consider the above problem, find out the Grashof number |
| A. | 0.8447 * 10 <sup>5</sup> |
| B. | 0.8447 * 10 <sup>6</sup> |
| C. | 0.8447 * 10 <sup>7</sup> |
| D. | 0.8447 * 10 <sup>8</sup> |
| Answer» C. 0.8447 * 10 <sup>7</sup> | |
| 4. |
A spherical heater of 20 cm diameter and at 60 degree Celsius is immersed in a tank of water at 20 degree Celsius. Determine the value of convective heat transfer coefficient |
| A. | 458.32 W/m<sup>2 </sup>K |
| B. | 558.32 W/m<sup>2 </sup>K |
| C. | 658.32 W/m<sup>2 </sup>K |
| D. | 758.32 W/m<sup>2 </sup>K |
| Answer» B. 558.32 W/m<sup>2 </sup>K | |
| 5. |
Consider the above problem, workout the heat losses from one meter length of the mains |
| A. | 0.458 |
| B. | 0.448 |
| C. | 0.438 |
| D. | 0.428 |
| Answer» D. 0.428 | |
| 6. |
Two horizontal steam mains with diameters 5 cm and 15 cm are to be laid in a boiler house that any mutual heat effect is precluded. The mains are at the same surface temperature of 500 degree Celsius whilst the ambient air is at 50 degree Celsius. Workout the ratios of the heat transfer coefficients |
| A. | 0.136 |
| B. | 1.316 |
| C. | 2.136 |
| D. | 3.136 |
| Answer» C. 2.136 | |
| 7. |
Experimental results indicate that the local heat transfer coefficient h g for flow over a flat plate with an extremely rough surface is approximated by the relation
|
| A. | nWhere a is a constant coefficient and x is distance from the leading edge of the plate. What is the relation between this local heat transfer coefficient and the average heat transfer coefficient for a plate of length x? |
| B. | 1.136 h <sub>x</sub> |
| C. | 2.136 h <sub>x</sub> |
| D. | 3.136 h <sub>x</sub> |
| E. | 4.136 h <sub>x</sub> |
| Answer» B. 1.136 h <sub>x</sub> | |
| 8. |
In respect to free convection over a vertical flat plate, the Nusselt number for laminar and turbulent flows varies respectively with Grashoff number G r as |
| A. | G <sub>r</sub> and G <sub>r</sub><sup>1/4</sup> |
| B. | G <sub>r</sub><sup>1/2</sup> and G <sub>r</sub><sup>1/3</sup> |
| C. | G <sub>r</sub><sup>1/4</sup> and G <sub>r</sub><sup>1/3</sup> |
| D. | G <sub>r</sub><sup>1/3</sup> and G <sub>r</sub><sup>1/4</sup> |
| Answer» D. G <sub>r</sub><sup>1/3</sup> and G <sub>r</sub><sup>1/4</sup> | |