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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

7. How many types of convection process are there?
a. One
b. Three
c. Four
d. Two
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Answer: (b).Three

8. Thermal conductivity is maximum for which substance
a. Silver
b. Ice
c. Aluminum
d. Diamond
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Answer: (d).Diamond

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

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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