All India Engineering / Architecture Entrance Examination (AIEEE) 
            CBSE Guess >  AIEEE >  AIEEE  Papers > 2008 > Physics 
            AIEEE 2008 Physics 
              
                                                 
            Directions: Questions No. 76 and 77 are based on the following paragraph  
            Consider a block of conducting material of resistivity  'p' shown in the figure. Current 'I' enters at 'A' and leaves from 'D'. We apply superposition principal to find voltage  ''developed between 'B' and 'C'. The calculation is done in the following steps:' 
            
              - Take current 'I' entering from 'A' and assume it to spread over a hemispherical surface in the block.
 
              - Calculate field E(r) at distance 'r' from A by using Ohm's law E = 'j' where 'j' 
  is the current per unit area at 'r'.  
              - From the-r' dependence of E(r), obtain the potential V(r) at 'r'. 
 
              - Repeat (i), (ii) and (iii) for current 'I' leaving 'D' and superpose results for'A' and 'D'.
 
             
              
            Q. 6.   measured between B and C is 
            
                
                
                
                
             
            Sol: 
              
                  
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