Question

Determine the factor of change for the electric force if the distance is changed by a factor of 3 and the charges of one of particles is changed by a factor of 4

Answer 1

Take into account that the electric force between two charges q1 and q2, separated by a distance r, is given by:

`F=K(q_1q_2)/(r^2)`

where K is the Coulomb's constant.

If r is changed to 3r and q1 is changed to 4q1, the new force F' is given by:

`\begin{gathered} F^(\prime)=K((4q_1)(q_2))/((3r)^2)=(4)/(9)K(q_1q_2)/(r^2) \\ F^(\prime)=(4)/(9)F \end{gathered}`

Hence, the factor of change of the electric force is 4/9