Charges `+q` and `-q` are located at the corners of a cube of side as show in the figure. Find the work done to separate the charges to infinite distance

Answer

`(1)/(4 pi epsilon_0) (q^2)/a . (4)/sqrt(6) [ 3sqrt(3) - 3 sqrt(6) - sqrt(2)]`

Explanation

`W_("external") = Delta P E = (1)/(4 pi epsilon_0) (q^2)/a [-(3)/(1) + (3)/sqrt(2) - (1)/sqrt(3)] xx 4`
=`(1)/(4 pi epsilon_0) (q^2)/a xx (4)/sqrt(6) [3 sqrt(3) - 3 sqrt(6) -sqrt(2)]`.