Page 27 - Electrostatics-11
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© GC Shiba
               Comparing the dimensions from both sides,

                                                                   1         1
                                                     = 0,    = − ,    =
                                                                   2         2
               Putting the value of a, b, c in eq (i), we get


                                                                    0 −1/2
                                                       =      1/2      
                                                                       1/2
                                                           ,    =   
                                                                       1/2


                                                                           
                                                          ,    =       √
                                                                          


               Experimentally value of k is found to be 2  


                                                                              
                                                   ∴,          = 2      √
                                                                             



     iii.  To  convert  a  physical  quantity  from one  system  into another  system  of

            units.

        For this, we use the relation            
                                              1 1= 2 2

        Here,       = numerical values                           = units in two systems
                  1 2
                                                            1 2

                                                                            
                                                                                
                                                                                    
                                                         
                                                 
                                       × [            ] =    × [             ]
                                                                2
                                     1
                                                                                  2
                                                   1 1
                                                                              2
                                                                          2
                                               1
                                                            1         1         1    
                                            ,    =    (      ) ( ) ( )
                                                      1
                                              2
                                                            2         2       2
        E.g.: Convert 5 N into dyne.
         In S.I. system (given system)                        In CGS system (new system)
         M1= 1 kg                                             M2= 1 g
         L1=1 m                                               L2=1 cm
         T1= 1 sec                                            T2= 1 sec

         n1=5                                                 n2=?
        Here,  given  physical  quantity  is  force.  So,  it’s  dimensional  formula  for  force

        [F]= [        −2 ].          ∴,    = 1,    = 1,    = −2


        4                                                                                       Mechanics
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