if the distance between two positive point charges is tripled,then the strength of the electrostatic repulsion between them will decrease by a factor of??

the strength of repulsion is proportional to 1/r², therefore is r is tripled repulsion strength will decrease by a factor of 9

Force 1 (F1) = kqXq/rXr

Force 2 (F2) = kqXq/9rXr      ( now r will become 3r )

F2/F1 = 1/9

so we can say that if distance between to positive charges is tripled then the electrostatic repulsion between them will become 1/9 or one ninth of the orignal value.

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9