MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 362 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 351. |
Film coefficient is defined as the ratio of |
| A. | Thermal conductivity to the equivalent thickness of the film of fluid |
| B. | Temperature drop through the films of fluids to the thickness of film of fluids |
| C. | Thickness of film of fluid to the thermal conductivity |
| D. | Thickness of film of fluid to the temperature drop through the films of fluids |
| Answer» B. Temperature drop through the films of fluids to the thickness of film of fluids | |
| 352. |
Unit of thermal diffusivity is |
| A. | m²/hr |
| B. | m²/hr °C |
| C. | kcal/m² hr |
| D. | kcal/m. hr °C |
| Answer» B. m¬¨‚â§/hr ¬¨‚àûC | |
| 353. |
In heat transfer, conductance equals conductivity (kcal/hr/sq.m/°C/cm) divided by# |
| A. | Hr (time) |
| B. | Sq. m (area) |
| C. | °C (temperature) |
| D. | K.cal (heat) |
| Answer» E. | |
| 354. |
Heat conducted through per unit area and unit thick face per unit time when temperature difference between opposite faces is unity, is called |
| A. | Thermal resistance |
| B. | Thermal coefficient |
| C. | Temperature gradient |
| D. | Thermal conductivity |
| Answer» E. | |
| 355. |
Conduction is a process of heat transfer |
| A. | From one particle of the body to another without the actual motion of the particles |
| B. | From one particle of the body to another by the actual motion of the heated particles |
| C. | From a hot body to a cold body, in a straight line, without affecting the intervening medium |
| D. | None of the above |
| Answer» B. From one particle of the body to another by the actual motion of the heated particles | |
| 356. |
The unit of overall coefficient of heat transfer is |
| A. | kcal/m² |
| B. | kcal/hr °C |
| C. | kcal/m² hr °C |
| D. | kcal/m hr °C |
| Answer» D. kcal/m hr ¬¨‚àûC | |
| 357. |
When heat is transferred from hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | Conduction and convection |
| Answer» D. Conduction and convection | |
| 358. |
Absorptivity of a body will be equal to its emissivity |
| A. | At all temperatures |
| B. | At one particular temperature |
| C. | When system is under thermal equilibrium |
| D. | At critical temperature |
| Answer» D. At critical temperature | |
| 359. |
If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ, and λ + dλ is represented by (eλ.dλ), then eλ is called# |
| A. | Absorptive power |
| B. | Emissive power |
| C. | Emissivity |
| D. | None of these |
| Answer» C. Emissivity | |
| 360. |
Upto the critical radius of insulation, |
| A. | Added insulation will increase heat loss |
| B. | Added insulation will decrease heat loss |
| C. | Convective heat loss will be less than conductive heat loss |
| D. | Heat flux will decrease |
| Answer» B. Added insulation will decrease heat loss | |
| 361. |
Which of the following is a case of steady state heat transfer? |
| A. | I.C. engine |
| B. | Air preheaters |
| C. | Heating of building in winter |
| D. | None of the above |
| Answer» E. | |
| 362. |
According of Kirchhoff's law |
| A. | Radiant heat is proportional to fourth power of absolute temperature |
| B. | Emissive power depends on temperature |
| C. | Emissive power and absorptivity are constant for all bodies |
| D. | Ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body |
| Answer» E. | |