Answer:
Step-by-step explanation:
We shall find first the distance where electric field is E/4 .
Let the charge be Q and distance be d where electric field is E . From the coulomb's Law
E = k Q / d²
Let distance be d₁ where field is E/4
E/4 = kQ / d₁²
Dividing the two equation
4 = d₁² / d²
d₁ = 2d
We shall have to find Potential at d₁ which is equal to 2 d .
Potential at d₁
V = k Q / 2d
= kQ d / 2d²
= E d / 2 . where d is distance of the point where field is E .