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. |
“If β is less than zero, then with respect to the relation k = k0 (1 + β t), conductivity depends on surface area”. |
| A. | True |
| B. | False |
| Answer» C. | |
| 2. |
The temperatures on the two sides of a plane wall are t1 and t2 and thermal conductivity of the wall material is prescribed by the relationK = k0 e (-x/δ)Where, k0 is constant and δ is the wall thickness. Find the relation for temperature distribution in the wall? |
| A. | t 1 – t x / t 1 – t 2 = x |
| B. | t 1 – t x / t 1 – t 2 = δ |
| C. | t 1 – t x / t 1 – t 2 = δ/x |
| D. | t 1 – t x / t 1 – t 2 = x/δ |
| Answer» E. | |
| 3. |
The unit of thermal conductivity doesn’t contain which parameter? |
| A. | Watt |
| B. | Pascal |
| C. | Meter |
| D. | Kelvin |
| Answer» C. Meter | |
| 4. |
If β is greater than zero, then choose the correct statement with respect to given relationk = k0 (1 +β t) |
| A. | k doesn’t depend on temperature |
| B. | k depends on temperature |
| C. | k is directly proportional to t |
| D. | Data is insufficient |
| Answer» D. Data is insufficient | |
| 5. |
The accompanying sketch shows the schematic arrangement for measuring the thermal conductivity by the guarded hot plate method. Two similar 1 cm thick specimens receive heat from a 6.5 cm by 6.5 cm guard heater. When the power dissipation by the wattmeter was 15 W, the thermocouples inserted at the hot and cold surfaces indicated temperatures as 325 K and 300 K. What is the thermal conductivity of the test specimen material? |
| A. | 0.81 W/m K |
| B. | 0.71 W/m k |
| C. | 0.61 W/m K |
| D. | 0.51 W/m K |
| Answer» C. 0.61 W/m K | |
| 6. |
With respect to the equation k = k0 (1 +β t) which is true if we put β = 0? |
| A. | Slope of temperature curve is constant |
| B. | Slope of temperature curve does not change |
| C. | Slope of temperature curve increases |
| D. | Slope of temperature curve is decreases |
| Answer» B. Slope of temperature curve does not change | |
| 7. |
A plane wall of thickness δ has its surfaces maintained at temperatures T1 and T2. The wall is made of a material whose thermal conductivity varies with temperature according to the relation k = k0 T2. Find the expression to work out the steady state heat conduction through the wall? |
| A. | Q = 2A k0 (T 1 3 – T 2 3)/3 δ |
| B. | Q = A k0 (T 1 3 – T 2 3)/3 δ |
| C. | Q = A k0 (T 1 2 – T 2 2)/3 δ |
| D. | Q = A k0 (T 1 – T 2)/3 δ |
| Answer» C. Q = A k0 (T 1 2 – T 2 2)/3 δ | |
| 8. |
The inner and outer surfaces of a furnace wall, 25 cm thick, are at 300 degree Celsius and 30 degree Celsius. Here thermal conductivity is given by the relationK = (1.45 + 0.5 * 10-5 t2) KJ/m hr degWhere, t is the temperature in degree centigrade. Calculate the heat loss per square meter of the wall surface area? |
| A. | 1355.3 kJ/m2 hr |
| B. | 2345.8 kJ/m2 hr |
| C. | 1745.8 kJ/m2 hr |
| D. | 7895.9 kJ/m2 hr |
| Answer» D. 7895.9 kJ/m2 hr | |
| 9. |
“If β is less than zero, then with respect to the relation k = k0 (1 + β t), conductivity depends on surface area”.$# |
| A. | True |
| B. | False |
| Answer» C. | |
| 10. |
The unit of thermal conductivity doesn’t contain which parameter?# |
| A. | Watt |
| B. | Pascal |
| C. | Meter |
| D. | Kelvin |
| Answer» C. Meter | |
| 11. |
If β is greater than zero, then choose the correct statement with respect to given relation$ |
| A. | |
| B. | k doesn’t depend on temperature |
| C. | k depends on temperature |
| D. | k is directly proportional to t |
| Answer» D. k is directly proportional to t | |
| 12. |
With respect to the equation k = k0 (1 +β t) which is true if we put β = 0?$ |
| A. | Slope of temperature curve is constant |
| B. | Slope of temperature curve does not change |
| C. | Slope of temperature curve increases |
| D. | Slope of temperature curve is decreases |
| Answer» B. Slope of temperature curve does not change | |
| 13. |
The mean thermal conductivity evaluated at the arithmetic mean temperature is represented by |
| A. | k<sub>m</sub> = k<sub>0</sub> [1 + β (t<sub>1</sub> – t<sub>2</sub>)/2]. |
| B. | k<sub>m</sub> = k<sub>0</sub> [1 + (t<sub>1</sub> + t<sub>2</sub>)/2]. |
| C. | k<sub>m</sub> = k<sub>0</sub> [1 + β (t<sub>1</sub> + t<sub>2</sub>)/3]. |
| D. | k<sub>m</sub> = k<sub>0</sub> [1 + β (t<sub>1</sub> + t<sub>2</sub>)/2]. |
| Answer» E. | |
| 14. |
A plane wall of thickness δ has its surfaces maintained at temperatures T1 and T2. The wall is made of a material whose thermal conductivity varies with temperature according to the relation k = k0 T2. Find the expression to work out the steady state heat conduction through the wall?$ |
| A. | Q = 2A k<sub>0</sub> (T <sub>1 </sub><sup>3</sup> – T <sub>2 </sub><sup>3</sup>)/3 δ |
| B. | Q = A k<sub>0</sub> (T <sub>1 </sub><sup>3</sup> – T <sub>2 </sub><sup>3</sup>)/3 δ |
| C. | Q = A k<sub>0</sub> (T <sub>1 </sub><sup>2</sup> – T <sub>2 </sub><sup>2</sup>)/3 δ |
| D. | Q = A k<sub>0</sub> (T <sub>1</sub> – T <sub>2</sub>)/3 δ |
| Answer» C. Q = A k<sub>0</sub> (T <sub>1 </sub><sup>2</sup> ‚Äö√Ñ√∂‚àö√ë‚àö¬® T <sub>2 </sub><sup>2</sup>)/3 ‚âà√≠¬¨‚Ä¢ | |
| 15. |
The inner and outer surfaces of a furnace wall, 25 cm thick, are at 300 degree Celsius and 30 degree Celsius. Here thermal conductivity is given by the relation |
| A. | KJ/m hr deg |
| B. | |
| C. | 1355.3 kJ/m<sup>2</sup> hr |
| Answer» D. | |
| 16. |
With variable thermal conductivity, Fourier law of heat conduction through a plane wall can be expressed as |
| A. | Q = -k<sub>0</sub> (1 + β t) A d t/d x |
| B. | Q = k<sub>0</sub> (1 + β t) A d t/d x |
| C. | Q = – (1 + β t) A d t/d x |
| D. | Q = (1 + β t) A d t/d x |
| Answer» B. Q = k<sub>0</sub> (1 + ‚âà√≠‚Äö√¢¬ß t) A d t/d x | |