MCQOPTIONS
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MCQOPTIONS
This section includes 5 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. |
A metal sphere of surface area 0.0225 m2 is in an evacuated enclosure whose walls are held at a very low temperature. Electric current is passed through resistors embedded in the sphere causing electrical energy to be dissipated at the rate of 75 W. If the sphere surfaces temperature is measured to be 560 K, while in steady state, calculate emissivity of the sphere surface |
| A. | 0.498 |
| B. | 0.598 |
| C. | 0.698 |
| D. | 0.798 |
| Answer» C. 0.698 | |
| 2. |
A furnace emits radiation at 2000 K. Treating it as a black body radiation, calculate the monochromatic radiant flux density at 1 micron m wavelength |
| A. | 5.81 * 10<sup> 7 </sup>W/m<sup>2</sup> |
| B. | 4.81 * 10<sup> 7 </sup>W/m<sup>2</sup> |
| C. | 3.81 * 10<sup> 7 </sup>W/m<sup>2</sup> |
| D. | 2.81 * 10<sup> 7 </sup>W/m<sup>2</sup> |
| Answer» E. | |
| 3. |
Planck s law is given by |
| A. | (E) <sub>b </sub>= 2 c<sup> 2 </sup>h (Wavelength)<sup> -5</sup>/[c h/k (Wavelength) T] 2 |
| B. | (E) <sub>b </sub>= c<sup> 2 </sup>h [exponential [c h/k (Wavelength) T] 3]. |
| C. | (E) <sub>b </sub>= 2 c<sup> 2 </sup>h (Wavelength)<sup> -5</sup>/exponential [c h/k (Wavelength) T] 1 |
| D. | (E) <sub>b </sub>= 2 c<sup> 2 </sup>h (Wavelength)<sup> -5</sup>/exponential [c h/k (Wavelength) T] 6 |
| Answer» D. (E) <sub>b </sub>= 2 c<sup> 2 </sup>h (Wavelength)<sup> -5</sup>/exponential [c h/k (Wavelength) T] 6 | |
| 4. |
The Planck s constant h has the dimensions equal to |
| A. | M L <sup>2 </sup>T <sup>-1</sup> |
| B. | M L T <sup>-1</sup> |
| C. | M L T <sup>-2</sup> |
| D. | M L T |
| Answer» B. M L T <sup>-1</sup> | |
| 5. |
The sun emits maximum radiation of 0.52 micron meter. Assuming the sun to be a black body, Calculate the emissive ability of the sun s surface at that temperature |
| A. | 3.47 * 10 <sup>7 </sup>W/m<sup>2</sup> |
| B. | 4.47 * 10 <sup>7 </sup>W/m<sup>2</sup> |
| C. | 5.47 * 10 <sup>7 </sup>W/m<sup>2</sup> |
| D. | 6.47 * 10 <sup>7 </sup>W/m<sup>2</sup> |
| Answer» D. 6.47 * 10 <sup>7 </sup>W/m<sup>2</sup> | |