There is an infinite straight  chain of alternating  charges `q` and `-q` . The distance between
Channel: Doubtnut
Date: 2020-08-23

There is an infinite straight  chain of alternating  charges `q` and `-q` . The distance between  teh neighbouring  charges is equal  to `a`. Find the interaction energy of each charge with all the others.  Instruction . Make  use of the expansion of In `(1 + alpha)` in a power  series in `alpha`.