Four point charges Q, q, Q and q are placed at the corners of a square of side' a' as shown in the figure.
Find the .
(a) resultnat electric force on a charge Q and .
(b) potential energy of this system.

Explanation

(a) `F_(1) to ` Force act at Q by q
`F_(2) to ` Force act at Q by Q
`F_(1) = (kqQ)/(a^(2)) " "F_(2) = (KQ^(2))/(2a^(2))`
`F_("net") = sqrt(2)F_(1) + F_(2) = sqrt(2) (KQq)/(a^(2)) + (ka^(2))/(2a^(2))`
(b ) Potential energy of system
`w_(1) = (kQq)/(a^(2)) " "w_(2) = (kq^(2))/(sqrt(2)a)`
`w_(3) = (KQq)/(a) " "w_(4) = (kq^(2))/(a)`
`w_(5) = (kq^(2))/(a) " "w_(6) = (KQq)/(sqrt(2)a)`
`w = w_(1) + w_(2) + w_(3)+w_(4) + w_(5) + w_(6)`