Question

the charges 1C and 5C are separated by a distance 20cm.what will be the ratio of electrostatic force acting on them?

Answer 1

Due to each other? 1 to 1 or 1 to -1 accounting for opposite directions.. Newton's third law. k Q1 Q2 / d^2 = k Q2 Q1 / d^2 :)

Answer 2

Now if you mean on each due to an external E field, THEN 5/1
k Q E