Question

If the force between two point charge is f find new force when distance is increased by 50%

Answer 1

(4/9)*f.

As distance is increased by 50%, new distance will be 3d/2.

Substituting, we get (4/9)*f.

Answer 2

We know

Force between two point charge is given by

F₁ = k q₁q₂/r²

where q₁q₂ = two points charge and

r = distance between the point charge

To determine the force when the distance between two point charge is increased by 50% = ?

F₂ = k q₁q₂/(0.5 r)²

F₂ = k q₁q₂/0.25 r²

F₂ = 4(k q₁q₂/ r²)

F₂ = 4 F₁

Thus when the distance between the point charge is increased by 50% its force will increase by 4 times the initial force.