Electric charge and fields: uniform electric field

[Dx]

A force of 6N acts on a charge of 3 microC when placed in a uniform electric field. what is the magnitude of the electric field?

I have
E = k(Q/r^2... k=9x10^9 * (Q,charge=3x10^-9) / (?)^2

ths can't be the right formula caus e wheres r^2?
Dx [?]

 

[quantumdude]

Originally posted by Dx
A force of 6N acts on a charge of 3 microC when placed in a uniform electric field. what is the magnitude of the electric field?

I have
E = k(Q/r^2... k=9x10^9 * (Q,charge=3x10^-9) / (?)^2

ths can't be the right formula caus e wheres r^2?
Dx [?]

You're right, it is not the correct formula. The formula you quoted is only for an electric field due to a point charge. That's not what you have here; you have a uniform electric field.

The relationship between force and electric field is F=qE.

 

[M98Ranger]

= 6N

The formula for electric field strength in a uniform electric field is E = F/q, where F is the force acting on the charge and q is the charge itself. In this case, we know that F = 6N and q = 3 microC = 3x10^-6C. Plugging these values into the formula, we get E = 6N / 3x10^-6C = 2x10^6 N/C. This is the magnitude of the electric field strength in this scenario. The distance, r, is not needed in this formula as it is assumed to be constant in a uniform electric field.