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        | Engineering  :: Heat Transfer |  | 
	 
 
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                | 141. | Thermal conductivity of wood least depends on |  
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				| A. | Moisture | B. | Density |  
				 				 | C. | Temperature | D. | Grain orientation |  
				    | E. | All of the above |  |  |  
                        
                        
                            Answer: Option D Explanation:    |  
 
            
            
                | 142. | In air prelieater for boiler heat is least transferred by |  
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				| A. | Conduction | B. | Convection |  
				 				 | C. | Conduction and convection | D. | Radiation |  
				    | E. | Conduction, convection and radiation. |  |  |  
                        
                        
                            Answer: Option D Explanation:    |  
 
            
            
                | 143. | Which method can be used for heating wood? |  
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				| A. | Flame heating | B. | Resistance heating |  
				 				 | C. | Dielectric heating | D. | Radiation heating |  
				    | E. | Any of the above |  |  |  
                        
                        
                            Answer: Option C Explanation:    |  
 
            
            
                | 144. | The total solar radiation incident on a body is 1000 kcal/min. The body reflects 400 kcal/min. If the transmissivity of the surface will be |  
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                            Answer: Option D Explanation:    |  
 
            
            
                | 145. | The phenomenon of boiling the milk in an open container when milk spills over the vessel is termed as |  
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				| A. | Film boiling | B. | Pool boiling |  
				 				 | C. | Nuclear boiling | D. | Sub-cooled boiling |  
				    | E. | Interface evaporation |  |  |  
                        
                        
                            Answer: Option A Explanation:    |  
 
            
            
                | 146. | The value of the wavelength for maximum emissive power is given by |  
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				| A. | Planck's law | B. | D'Alembert's rule |  
				 				 | C. | Kirchhoff's law | D. | Stefan law |  
				    | E. | Wein's law |  |  |  
                        
                        
                            Answer: Option E Explanation:    |  
 
            
            
                | 147. | Which type of heat exchanger an automobile radiator is? |  
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				| A. | Parallel flow type | B. | Counter flow type |  
				 				 | C. | Recuperator type | D. | Regenerator type |  
				    | E. | Cross flow type |  |  |  
                        
                        
                            Answer: Option E Explanation:    |  
 
            
            
                | 148. | A hollow sphere with uniform interior temperature and a small hole behaves very nearly as a |  
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				| A. | Grey body | B. | White body |  
				 				 | C. | Opaque body | D. | Transparent body |  
				    | E. | Black body |  |  |  
                        
                        
                            Answer: Option E Explanation:    |  
 
            
            
                | 149. | A body which transmits all the radiations falling on it is known as |  
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				| A. | Black body | B. | Grey body |  
				 				 | C. | Transparent body | D. | White body |  
				    | E. | None of the above |  |  |  
                        
                        
                            Answer: Option C Explanation:    |  
 
            
            
                | 150. | A black body absorbs all radiations. As a result of absorption of these radiations |  
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				| A. | A black body shines | B. | The temperature of black body rises |  
				 				 | C. | Black body radiates energy to other bodies | D. | Black body becomes good conductor of heat |  
                        
                        
                            Answer: Option B Explanation:    |  
 
 
			
			
 
 
 
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