16. Match the property with their units
    

    Property	Units
    A. Bulk modulus	1. W/s
    B. Thermal conductivity	2. N/m2
    C. Heat transfer coefficient	3. N/m3
    D. Heat flow rate	4. W
    	5. W/mK
    	6. W/m2K

    
    

1. 1. A - 1 , B - 2 , C - 6 , D - 5
      

   
   
   

   2. A - 2 , B - 5 , C - 6 , D - 1
      

   
   
   

   3. A - 2 , B - 6 , C - 4 , D - 1
      

   
   
   

   4. A - 1 , B - 5 , C - 3 , D - 2

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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17. Thermal conductivity is lower for
    

1. 1. wood
      

   
   
   

   2. air
      

   
   
   

   3. water at 100°C
      

   
   
   

   4. steam at 1 bar

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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18. A solid sphere 1 of radius r is placed inside a hollow, closed hemispherical surface 2 of radius 4r. The shape factor F is,
    
    

1. 1. 	1
      	12

      
      

   
   
   

   2. 1

      2

      
      

   
   
   

   3. 2
      

   
   
   

   4. 12

   
   
   

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1. View Hint View Answer Discuss in Forum

   f ₁₁ + f ₁₂ = 1
   ∴ f ₁₂ = 1
   f ₂₁ A₂ = f ₁₂ A₁
   

   ∴ f21 =	f12A1	=	1 × 4πr2	=	V	=	1
   	A2		k		(1 / 2)4π(4r)2 + π(4r)2		12

   Correct Option: A

   f ₁₁ + f ₁₂ = 1
   ∴ f ₁₂ = 1
   f ₂₁ A₂ = f ₁₂ A₁
   

   ∴ f21 =	f12A1	=	1 × 4πr2	=	V	=	1
   	A2		k		(1 / 2)4π(4r)2 + π(4r)2		12

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19. A diffuse radiation surface has
    

1. 1. Radiation intensity Independent of angle
      

   
   
   

   2. Emissive power Independent of angle
      

   
   
   

   3. Emissive power independent of wavelength
      

   
   
   

   4. Radiation intensity Independent of both angle and wavelength

   
   
   

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1. View Hint View Answer Discuss in Forum

   Radiation intensity is independent of angle in diffuse radiation.

   Correct Option: A

   Radiation intensity is independent of angle in diffuse radiation.

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20. What is the value of the view factor for two inclined flat plates having common edge of equal length and wlth an angle of 20 degrees?
    

1. 1. 0.83
      

   
   
   

   2. 1.17
      

   
   
   

   3. 0.66
      

   
   
   

   4. 1.34

   
   
   

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1. View Hint View Answer Discuss in Forum

   F12 = F21 = 1 - sin		θ
   		2

   
   

   = 1 - sin		20°		= 0.826
   		2

   Correct Option: A

   F12 = F21 = 1 - sin		θ
   		2

   
   

   = 1 - sin		20°		= 0.826
   		2

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