MCQOPTIONS
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MCQOPTIONS
This section includes 14 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. |
Which of the following is a wrong statement in the context of a convective heat transfer coefficient in laminar film condensation?The heat transfer coefficient varies as |
| A. | – ¼ power of acceleration due to gravity |
| B. | ½ power of density of liquid |
| C. | ¼ power of enthalpy of evaporation |
| D. | – ½ power of dynamic viscosity |
| Answer» B. ½ power of density of liquid | |
| 2. |
The critical Reynolds number for transition from laminar to turbulent film condensation is |
| A. | 2000 |
| B. | 1900 |
| C. | 1800 |
| D. | 1700 |
| Answer» D. 1700 | |
| 3. |
Determine the length of a 25 cm outer diameter tube if the condensate formed on the surface of the tube is to be same whether it is kept vertical or horizontal |
| A. | 61.5 cm |
| B. | 71.5 cm |
| C. | 81.5 cm |
| D. | 91.5 cm |
| Answer» C. 81.5 cm | |
| 4. |
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 – y 2)/σ |
| C. | p g (δ y – y 2/2)/σ |
| D. | p g (δ – y 2/2)/σ |
| Answer» D. p g (δ – y 2/2)/σ | |
| 5. |
THE_CRITICAL_REYNOLDS_NUMBER_FOR_TRANSITION_FROM_LAMINAR_TO_TURBULENT_FILM_CONDENSATION_IS?$ |
| A. | 2000 |
| B. | 1900 |
| C. | 1800 |
| D. | 1700 |
| Answer» D. 1700 | |
| 6. |
Which_of_the_following_is_a_wrong_statement_in_the_context_of_a_convective_heat_transfer_coefficient_in_laminar_film_condensation?$ |
| A. | |
| B. | – ¼ power of acceleration due to gravity |
| C. | ¬Ω power of density of liquid |
| Answer» B. ‚Äö√Ñ√∂‚àö√ë‚àö¬® ¬¨¬®¬¨‚à´ power of acceleration due to gravity | |
| 7. |
Determine the length of a 25 cm outer diameter tube if the condensate formed on the surface of the tube is to be same whether it is kept vertical or horizonta? |
| A. | 61.5 cm |
| B. | 71.5 cm |
| C. | 81.5 cm |
| D. | 91.5 cm |
| Answer» C. 81.5 cm | |
| 8. |
A plate condenser of dimensions l * b has been designed to be kept with side l in the vertical position. However due to oversight during erection and installation, it was fixed with side b vertical. How would this affect the heat transfer? Assume laminar conditions and same thermos-physical properties and take b = l/2 |
| A. | The condenser should be installed with shorter side horizontal |
| B. | The condenser should be installed with longer side horizontal |
| C. | The condenser should be installed with longer side vertical |
| D. | The condenser should be installed with shorter side vertical |
| Answer» E. | |
| 9. |
Mark the wrong statement with respect to laminar flow condensation on a vertical plate |
| A. | The rate of condensation heat transfer is maximum at the upper edge of the plate and progressively decreases as the lower edge is approached |
| B. | The average heat transfer coefficient is two third of the local heat transfer coefficient at the lower edge of the plate |
| C. | At a definite point on the heat transfer, the film coefficient is directly proportional to thermal conductivity and inversely proportional to thickness of film at the point |
| D. | The film thickness increases as the fourth root of the distance down the upper edge |
| Answer» C. At a definite point on the heat transfer, the film coefficient is directly proportional to thermal conductivity and inversely proportional to thickness of film at the point | |
| 10. |
For laminar film condensation on a vertical plate, the local heat transfer coefficient at the lower edge of the plate is given by |
| A. | [k <sup>3</sup> p<sup> 2</sup> g h <sub>f g </sub>/4 δ l (t <sub>sat</sub> – t <sub>s</sub>)] <sup>0.25</sup> |
| B. | [k <sup>3</sup> p<sup> 2</sup> g h <sub>f g </sub>/4 δ l (t <sub>sat</sub> – t <sub>s</sub>)] <sup>0.5</sup> |
| C. | [k <sup>3</sup> p<sup> 2</sup> g h <sub>f g </sub>/4 δ l (t <sub>sat</sub> – t <sub>s</sub>)] <sup>0.1</sup> |
| D. | [k <sup>3</sup> p<sup> 2</sup> g h <sub>f g </sub>/4 δ l (t <sub>sat</sub> – t <sub>s</sub>)] <sup>0.125</sup> |
| Answer» B. [k <sup>3</sup> p<sup> 2</sup> g h <sub>f g </sub>/4 ‚âà√≠¬¨‚Ä¢ l (t <sub>sat</sub> ‚Äö√Ñ√∂‚àö√ë‚àö¬® t <sub>s</sub>)] <sup>0.5</sup> | |
| 11. |
For laminar film condensation on a vertical plate, the gravitational acceleration g is replaced by |
| A. | 4 g sin α |
| B. | 3 g sin α |
| C. | 2 g sin α |
| D. | g sin α |
| Answer» E. | |
| 12. |
For laminar film condensation on a vertical plate, the mass flow rate of the condensate per unit depth of the film at any position x is given by |
| A. | p g δ <sup>3</sup>/ 3 |
| B. | p g δ <sup>3</sup>/ 3 σ |
| C. | p g δ <sup>2</sup>/ 3 σ |
| D. | p g δ <sup>2</sup>/ 3 |
| Answer» C. p g ‚âà√≠¬¨‚Ä¢ <sup>2</sup>/ 3 ‚âà√¨‚àö√¢ | |
| 13. |
For laminar film condensation on a vertical plate, the film thickness is given by |
| A. | [4 k δ (t <sub>sat</sub> – t <sub>s</sub>) x/p <sup>2</sup> g h <sub>f g</sub>]<sup> 0.25</sup> |
| B. | [4 k δ (t <sub>sat</sub> – t <sub>s</sub>) x/p <sup>2</sup> g h <sub>f g</sub>]<sup> 0.5</sup> |
| C. | [4 k δ (t <sub>sat</sub> – t <sub>s</sub>) x/p <sup>2</sup> g h <sub>f g</sub>]<sup> </sup> |
| D. | [4 k δ (t <sub>sat</sub> – t <sub>s</sub>) x/p <sup>2</sup> g h <sub>f g</sub>]<sup> 1.5</sup> |
| Answer» B. [4 k ‚âà√≠¬¨‚Ä¢ (t <sub>sat</sub> ‚Äö√Ñ√∂‚àö√ë‚àö¬® t <sub>s</sub>) x/p <sup>2</sup> g h <sub>f g</sub>]<sup> 0.5</sup> | |
| 14. |
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 – y <sup>2</sup>)/σ |
| C. | p g (δ y – y <sup>2</sup>/2)/σ |
| D. | p g (δ – y <sup>2</sup>/2)/σ |
| Answer» D. p g (‚âà√≠¬¨‚Ä¢ ‚Äö√Ñ√∂‚àö√ë‚àö¬® y <sup>2</sup>/2)/‚âà√¨‚àö√¢ | |