Calculating Electric Force Between Charges in a Dielectric Medium

AI Thread Summary
The discussion focuses on calculating the electric force between two charges in a dielectric medium. The user initially applied the formula F = kq1q2/r^2 but overlooked the need to include the permittivity constant in their calculations. It was clarified that the "k" in the formula represents Coulomb's constant, while the dielectric constant is denoted by κ (kappa). Additionally, placing a dielectric between charges actually reduces the electric force, contrary to the user's assumption. Accurate calculations require using the correct constants and understanding their roles in the formula.
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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.
 
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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?
 


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

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