6. | The rate equation used to describe the mechanism of convection is called Newton’s law of cooling. So rate of heat flow by convection doesn’t depend on |
a. | Convective heat transfer coefficient |
b. | Surface area through which heat flows |
c. | Time |
d. | Temperature potential difference |
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Answer: (c).Time
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7. | How many types of convection process are there? |
a. | One |
b. | Three |
c. | Four |
d. | Two |
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Answer: (b).Three
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8. | Thermal conductivity is maximum for which substance |
a. | Silver |
b. | Ice |
c. | Aluminum |
d. | Diamond |
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Answer: (d).Diamond
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9. | A radiator in a domestic heating system operates at a surface temperature of 60 degree Celsius. Calculate the heat flux at the surface of the radiator if it behaves as a black body |
a. | 697.2 W/m² |
b. | 786.9 W/m² |
c. | 324.7 W/m² |
d. | 592.1 W/m² |
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Answer: (a).697.2 W/m²
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10. | Which of the following is an example of forced convection? |
a. | Chilling effect of cold wind on a warm body |
b. | Flow of water in condenser tubes |
c. | Cooling of billets in the atmosphere |
d. | Heat exchange on cold and warm pipes |
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Answer: (b).Flow of water in condenser tubes
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