Two point charges `q_(1)andq_(2)` are located at `vecrandvecr_(2)` respectively in an external electric field E. Obtain the experession for the total work done in assembling this configuration .

Explanation

Work done in briginging the charge `q_(1)` from infinity to position `r_(1)`
`W_(1)=q_(1)V(r_(1))` Work done in bringing charge `q_(2)` to the position `r_(2)`
`W_(2)=q_(2)V(r_(2))+(q_(1)q_(2))/(4piepsilon_(0)r_(12))`
Hence , total work done in assembling the two charges
`W=W_(1)+W_(2)`
`=q_(1)V(r_(1))+q_(2)V(r_(2))+(q_(1)q_(2))/(4piepsilon_(0)r_(12))`