How do you find the direction and magnitude from a nucleus?

[itsmarasilly]

Homework Statement

The nucleus of an atom has a charge of 65 protons.

(a) What are the direction and magnitude of the electric field at 4.9 x 10^-10 m from the nucleus?

(b) What are the direction and magnitude of the force exerted on an electron located at this distance?

Homework Equations

E= KQ/d^2
K= 9 x 10^9

The Attempt at a Solution

(a) (9 x 10^9)(65)/(4.9 x 10^-10)^2
= 2.44e30 N

Please help clarify if (a) is correct, and what exactly is (b) asking, if any different from (a)?

 

[LowlyPion]

I think you need to understand what the charge of 65 protons is.
http://en.wikipedia.org/wiki/Proton

It is not 65 coulombs that are the units of the equation you used.

Having found the field, then b) is asking you to find the force.