MCQOPTIONS
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MCQOPTIONS
This section includes 10 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. |
Avoiding the Critical heat flux is an engineering problem in heat transfer applications, such as nuclear reactors, where fuel plates must not be allowed to overheat. To cope with this, what measure can be taken? |
| A. | Decrease the pressure |
| B. | Increase the pressure |
| C. | Add more water |
| D. | Add turbulence |
| Answer» C. Add more water | |
| 2. |
What is the term KL in the giver equation of Nusselt number for nucleate boiling heat transfer correlations? Nub = \(\frac{(\frac{q}{A})D_b}{(T_s-T_{sat})k_L}\) |
| A. | Thermal conductivity of the vapour |
| B. | Thermal conductivity of the liquid |
| C. | Thermal conductivity of the film |
| D. | Thermal conductivity of the Bubble |
| Answer» C. Thermal conductivity of the film | |
| 3. |
The Nusselt number for nucleate boiling is correctly represented by which equation? |
| A. | Nu=\(\frac{Q}{A}\) Db ⁄ (Ts-Tsat) KL |
| B. | Nu=\(\frac{Q}{A}\) Db(Ts-Tsat) KL |
| C. | Nu=\(\frac{Q}{A}\) Db (Ts-Tsat) ⁄ KL |
| D. | Nu=\(\frac{Q}{A}\) Db KL ⁄ (Ts-Tsat) |
| Answer» B. Nu=\(\frac{Q}{A}\) Db(Ts-Tsat) KL | |
| 4. |
The heat flux Q/A depends on the specific heat of the liquid Cf as which one of the following given? |
| A. | Q/A= δf hfg [(pf – pg) g/σ]0.55 [Cf dt/hfg p] 3 |
| B. | Q/A = δf hfg [(pf – pg) g/σ]0.6 [Cf dt/hfg p Csf]3 |
| C. | Q/A = δf hfg [(pf – pg) g/σ]0.5 [Cf dt/hfg p Csf]3 |
| D. | Q/A = δf hfg [(pf – pg) g/σ]0.5 [Cf dt/hfg p Csf] |
| Answer» D. Q/A = δf hfg [(pf – pg) g/σ]0.5 [Cf dt/hfg p Csf] | |
| 5. |
Consider a situation when evaporation takes place at the liquid-vapour interface in which the heat transfer is mainly due to free convection then the Nusselt Number for the film follows which one of the following relation? |
| A. | Nu = F1 Gr F2 Pr |
| B. | Nu = 4 F1 Gr F2 Pr |
| C. | Nu = 2 F1 Gr F2 Pr |
| D. | Nu = 3 F1 Gr F2 Pr |
| Answer» B. Nu = 4 F1 Gr F2 Pr | |
| 6. |
Which one of the following statement is incorrect? |
| A. | In sub-cool heating, the temperature of the heating surface is less than the normal boiling point of the liquid |
| B. | Nucleate boiling is promoted on a smooth surface than a rough one |
| C. | Film boiling region is usually avoided in commercial equipment |
| D. | The point of transition from nucleate to film boiling is known as the burn-out point on the boiling curve |
| Answer» C. Film boiling region is usually avoided in commercial equipment | |
| 7. |
Spherical bubbles of diameter 3 mm are observed in the bubble boiling phase of water at 1 atmosphere pressure. Assuming pure wateRvapour is present inside the bubbles, calculate the temperature of that vapour.Given Surface tension = 73mN/mR/pgfg = 0.000014What region of boiling is this ocurring if we consider the two answers we get? |
| A. | Evaporation and Bubble growth |
| B. | Stable film and Evaporation |
| C. | Unstable film and Radiation |
| D. | Nucleate and Stable film |
| Answer» E. | |
| 8. |
Spherical bubbles of diameter 3 mm are observed in the bubble boiling phase of water at 1 atmosphere pressure. Assuming pure water vapour is present inside the bubbles, calculate the temperature of that vapour.Given Surface tension = 73mN/mR/pgfg = 0.000014 |
| A. | 119.387 ℃ |
| B. | 200.217 ℃ |
| C. | 300.217 ℃ |
| D. | 400.217 ℃ |
| Answer» B. 200.217 ℃ | |
| 9. |
What is the relation between the vapour temperature and the liquid temperature on nucleation for a bubble inside the fluid? |
| A. | Tv – Tsat = (2 σ/r – pg) Rv Tv/pv hfg |
| B. | Tv – Tsat = (2 σ/r – pg) Rv Tv2/pv hfg |
| C. | Tv – Tsat = (2 σ/r – pg) Rv Tv2pv hfg |
| D. | Tv – Tsat = (2 σ – pg) Rv Tv2/pv hfg |
| Answer» C. Tv – Tsat = (2 σ/r – pg) Rv Tv2pv hfg | |
| 10. |
The milk while boiling in an open vessel spills out because of the ___________ phenomenon. |
| A. | Sub-cooled boiling |
| B. | Super-cooled boiling |
| C. | Sub-heated boiling |
| D. | Super-heated boiling |
| Answer» B. Super-cooled boiling | |