Calculating Electric Force Between Charges in a Dielectric Medium

[Velocity.]

Electric force question help please!

I was just doing a question in my textbook and I got stuck on this question as my answer is no where near the given answer.

Two charges of magnitude 0.24 μC and 0.29 μC are in a liquid dielectric with dielectric constant κ = 2.0. The charges are separated by a distance of 0.42 m.

(i) What is the size of the electric force between the charges?

I got an answer of 3.314e-13N whilst theirs is 0.00177N


What am I doing wrong?? I'm using the F=kq1q2/r^2 formula, substituting 0.24 and 0.29 for q1/q2, using 2.0 as k and 0.42 for r.

 

[ak1948]

Recheck your formula; its quite wrong. For one thing, the permittivity constant is missing. Also do you think the electric force between charges is increased by placing a dielectric between them?

 

[Redbelly98]

The k constant in "F=k..." is different than the "k" (or Greek kappa?) used for the dielectric constant.