- #1

Issy

- 6

- 1

## Homework Statement

What is the magnitude of the electric field due to a 6.0 x 10

^{-9}C charge at a point located 0.025m from the charge? The charge and the point in question are located underwater (κ(water) = 80).

## Homework Equations

I know that E = magnitude of electric field = kq/r

^{2}, where k = Coulomb's constant of 9 x 10

^{9}, and I also know that κ = kappa = dielectric constant aka relative permittivity of a dielectric material, which we use in the equation C = capacitance = κε

_{o}A/d.

However, I can't workout how to use κ to find electric field strength, because I don't see how a capacitor is involved in this situation? And with the three variables I have been given (the size and electric polarity of charge, the distance, and the dielectric constant of water), I also don't know of any formulas I can use that don't require any other variables.

The practise test I'm working on is multichoice, and the answers state that the final answer is equal to 1.1 x 10

^{3}N/C, but I'm not sure how to work backwards from that either. Any help would be greatly appreciated! We have a test later this week, and I'm sure Murphy's Law will make sure that unless I get my head around it, a question like this will no doubt be in the exam, so any and all advice will be welcomed!