# Net Electric Field

• Nov 13th 2009, 02:08 AM
MarcoMP
Net Electric Field
There are two spheres. Sphere A = +4uC, Sphere B = -6uC. C is a point in the field.

A----------(40cm)----------B----(20cm)---C

Calculate the Net Electric Field felt by C.
Electric Field Strength: $E = K \frac{Q_1}{r^2}$

I got it to be $1 450 000 N.C^{-1}$ attraction towards B but i think this is incorrect. Any help please?
• Nov 17th 2009, 05:52 AM
HallsofIvy
Quote:

Originally Posted by MarcoMP
There are two spheres. Sphere A = +4uC, Sphere B = -6uC. C is a point in the field.

A----------(40cm)----------B----(20cm)---C

Calculate the Net Electric Field felt by C.
Electric Field Strength: $E = K \frac{Q_1}{r^2}$

I got it to be $1 450 000 N.C^{-1}$ attraction towards B but i think this is incorrect. Any help please?

Did you take into account that these are opposite signs and so would both push an electron in the same direction? It looks to me like you subtracted field strengths when you should have added (or, more correctly, subracted a negative value).