Question

Force of attraction between two point electric charges placed at a distance"d" in a medium is "F". What distance apart should these be kept in the same medium, so that force between them become F/3?

Answer 1

we are given

F = (k.q₁.q₂) / d²

or

d = [k.q₁.q₂) /F]^1/2

now,

for F' = 3F, the distance will be

d' = [k.q₁.q₂) /F']^1/2 = [k.q₁.q₂) / 3F]^1/2

or

d' = (1/√3).[k.q₁.q₂) /F]^1/2

so, distance

d' = d/√3

and

for F'' = F/3, the distance will be

d'' = [k.q₁.q₂) /F'']^1/2 = [k.q₁.q₂) / (F/3)]^1/2

or

d'' = (√3).[k.q₁.q₂) /F]^1/2

so, distance

d'' = d√3