Question

Four identical charges Q are fixed at the four corners of a square of side a. The electric field at a point P located symmetrically at a distance `a//sqrt(2)` from the center of the square is
A. `(Q)/(2sqrt(2)pi epsilon_(0)a^(2))`
B. `(Q)/(sqrt(2)pi epsilon_(0)a^(2))`
C. `(2sqrt(2)Q)/(pi epsilon_(0)a^(2))`
D. `(sqrt(2)Q)/(pi epsilon_(0)a^(2))`

Answer 1

Correct Answer - B
,
`E_("net")=4E cos theta=(4)/(4 pi epsilon_(0)) (Q)/(a^2) (1)/(sqrt(2))=(Q)/(sqrt(2)pi epsilon_(0)a^(2))`.