Question

There exist uniform electric field E= -E in space, four point charges are placed on vertices of a square as shown in the figure. What in minimum work required to exchange positions of point charges placed at(a, 0)and(0, 0)

• A. -4qEa
• B. 0
• C. 2qEa
• D. 4qEa

Answer 1

The correct option is A -4qEa

The distance $=\sqrt{a^2+0}=a$ unit

Work done $=F.d$

$=-4qEa$

$=-4qF$

$F=-4qE$

for four charges $=q+q+q+q=4q$

$(-Ve)$ sign because electric field in space is $(-ve)$ in sign

$E=$ Electric filed.