MCQOPTIONS
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MCQOPTIONS
This section includes 16 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. |
In case when both the surfaces of plane wall are at different temperature, we get an expression i.e.T MAX – T W2 /T W1 – TW2 = (B + 1)2/4BWhat is the value of B? |
| A. | (q g) (δ)2/2k (T W1 – TW2) |
| B. | (q g) (δ)3/3k (T W1 – TW2) |
| C. | (q g) (δ)4/4k (T W1 – TW2) |
| D. | (q g) (δ)5/5k (T W1 – TW2) |
| Answer» B. (q g) (δ)3/3k (T W1 – TW2) | |
| 2. |
Suppose heat is conducted due to electronsWhere, i = I/A and p is the resistivity, then |
| A. | q g = 2i2 p |
| B. | q g = 3i2 p |
| C. | q g = i2 p |
| D. | q g = 4i2 p |
| Answer» D. q g = 4i2 p | |
| 3. |
The rear window of an automobile is made of thick glass i.e. AB = 5 mm and thermal conductivity is 0.8 W/m degree. To defrost this window, a thin transparent film type heating element has been fixed to its inner surface. For the conditions given below, determine the electric power that must be provided per unit area of window if a temperature 5 degree Celsius is maintained at its outer surface. Interior air temperature and the corresponding surface coefficient are 20 degree Celsius and 12 W/m2 degree. Surrounding air temperature and the corresponding surface coefficient are – 15 degree Celsius and 70 W/m2 degree. Electric heater provides uniform heat flux |
| A. | 232.5 /m2 |
| B. | 1232.5 /m2 |
| C. | 2232.5 /m2 |
| D. | 3232.5 /m2 |
| Answer» C. 2232.5 /m2 | |
| 4. |
There occurs heat conduction and internal heat generation at uniform rate within the conduction medium itself in the following cases(i) Drying of concrete(ii) Chemical processes(iii) Fuel elements in a nuclear reactionChoose the correct option |
| A. | i only |
| B. | ii only |
| C. | i and iii |
| D. | i, ii and iii |
| Answer» E. | |
| 5. |
Consider a slab of thickness δ with one side (x = 0) insulated and other side (x = δ) maintained at constant temperature. The rate of uniform heat generation within the slab is q g W/m3. Presuming that the heat conduction is in steady state and one dimensional along x direction, the maximum temperature in the slab would occur at x equal |
| A. | δ/2 |
| B. | Zero |
| C. | δ/4 |
| D. | δ |
| Answer» C. δ/4 | |
| 6. |
For a plane wall of thickness l with uniformly distributed heat generation q g per unit volume, the temperature t 0 at mid plane is given by |
| A. | t 0 = q g l 2/2k +t w |
| B. | t 0 = q g l 2/4k +t w |
| C. | t 0 = q g l 2/8k +t w |
| D. | t 0 = q g l 2/16k +t w |
| Answer» D. t 0 = q g l 2/16k +t w | |
| 7. |
Notable example of uniform generation of heat within the conducting medium are(i) Energy of a nuclear reactor(ii) Liberation of energy due to some exothermic chemical reactions(iii) Resistance heating in electrical appliancesWhich of the statements made above are correct? |
| A. | i, ii and iii |
| B. | i and ii |
| C. | i and iii |
| D. | Only ii |
| Answer» B. i and ii | |
| 8. |
If Q X is heat generated in at distance ‘x’, then heat conducted out at a distance (x + d x) will be |
| A. | Q X + 3d (Q X) d x /d x |
| B. | 2Q X + d (Q X) d x /d x |
| C. | d (Q X) d x /d x |
| D. | Q X + d (Q X) d x /d x |
| Answer» E. | |
| 9. |
SUPPOSE_HEAT_IS_CONDUCTED_DUE_TO_ELECTRONS?$ |
| A. | |
| B. | q <sub>g</sub> = 2i<sup>2</sup> p |
| C. | q <sub>g</sub> = 3i<sup>2</sup> p |
| Answer» D. | |
| 10. |
In_case_when_both_the_surfaces_of_plane_wall_are_at_different_temperature,_we_get_an_expression_i.e.$ |
| A. | <sup>2</sup>/4B |
| B. | |
| C. | (q <sub>g</sub>) (δ)<sup>2</sup>/2k (T <sub>W1 </sub>– T<sub>W2</sub>) |
| Answer» B. | |
| 11. |
Consider a slab of thickness δ with one side (x = 0) insulated and other side (x = δ) maintained at constant temperature. The rate of uniform heat generation within the slab is q g W/m3. Presuming that the heat conduction is in steady state and one dimensional along x direction, the maximum temperature in the slab would occur at x equal$ |
| A. | δ/2 |
| B. | Zero |
| C. | δ/4 |
| D. | δ |
| Answer» C. ‚âà√≠¬¨‚Ä¢/4 | |
| 12. |
The temperature drop in a plane wall with uniformly distributed heat generation can be decreased by reducing |
| A. | Wall thickness |
| B. | Heat generation rate |
| C. | Thermal conductivity |
| D. | Surface area |
| Answer» B. Heat generation rate | |
| 13. |
For a plane wall of thickness l with uniformly distributed heat generation q g per unit volume, the temperature t 0 at mid plane is given by |
| A. | t <sub>0 </sub>= q<sub> g </sub>l <sup>2</sup>/2k +t <sub>w</sub> |
| B. | t <sub>0 </sub>= q<sub> g </sub>l <sup>2</sup>/4k +t <sub>w</sub> |
| C. | t <sub>0 </sub>= q<sub> g </sub>l <sup>2</sup>/8k +t <sub>w</sub> |
| D. | t <sub>0 </sub>= q<sub> g </sub>l <sup>2</sup>/16k +t <sub>w</sub> |
| Answer» D. t <sub>0 </sub>= q<sub> g </sub>l <sup>2</sup>/16k +t <sub>w</sub> | |
| 14. |
Notable example of uniform generation of heat within the conducting medium are |
| A. | Energy of a nuclear reactor |
| B. | Liberation of energy due to some exothermic chemical reactions |
| C. | Resistance heating in electrical appliances |
| Answer» B. Liberation of energy due to some exothermic chemical reactions | |
| 15. |
If Q X is heat generated in at distance ‘x’, then heat conducted out at a distance (x + d x) will be$ |
| A. | Q <sub>X </sub>+ 3d (Q <sub>X</sub>) d x /d x |
| B. | 2Q <sub>X </sub>+ d (Q <sub>X</sub>) d x /d x |
| C. | d (Q <sub>X</sub>) d x /d x |
| D. | Q <sub>X </sub>+ d (Q <sub>X</sub>) d x /d x |
| Answer» E. | |
| 16. |
In case of heat conduction through the plane wall, which one of the following is not a correct assumption? |
| A. | Steady state |
| B. | Three dimensional heat flow |
| C. | Volumetric heat generation must be constant |
| D. | K must be constant |
| Answer» C. Volumetric heat generation must be constant | |