Q:
      
      
         
            
Two metallic plate of equal thickness and coefficient thermal conductivity K1 and K2 put together face to face. A common plate is constructed. What is equivalent K? 
         
       
      
      
      
          
      
      
          Answer & Explanation
         Answer: B) 2k1k2/k1+k2         
         
Explanation: We know that,
 
The equivalent K =  
 
where L1 & L2 are plate1 & Plate2 thicknesses, K1 & K2 are coefficient thermal conductivity of plate1 & Plate2 respectively.
 
But here L1 = L2 = L (say)
 
Then K = L+L/(L/K1 + L/K2)  =  
       
      
      
      
          View Answer
          Report Error
          Discuss