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        | Engineering  :: Heat Transfer |  | 
	 
 
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                | 271. | The average value of thermal conductivity for water at 20?C is about |  
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				| A. | 0.13 | B. | 0.32 |  
				 				 | C. | 0.51 | D. | None of the above |  
                        
                        
                            Answer: Option C Explanation:    |  
 
            
            
                | 272. | The heat of sum reaches to us according to |  
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				| A. | radiation | B. | conduction |  
				 				 | C. | convection | D. | None of the above |  
                        
                        
                            Answer: Option A Explanation:    |  
 
 
			
			
 
 
 
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