Coulomb's Law and Gauss's law

• henrybrent
What is the problem?In summary, the conversation discusses the calculation of the force and electric dipole moment between two electric charges, as well as the electric flux through two spherical Gaussian surfaces centered at the origin. The formula used for the force is \vec{F_{12}} = \frac {1}{4\pi\epsilon_0}\frac{q_1q_2}{|\vec{r_1}-\vec{r_2}|^3}(\vec{r_1}-\vec{r_2}), and the resulting force on q1 is (-0.013, 0, -0.013)N. The electric dipole moment is calculated using the formula P = qD, where

henrybrent

User informed about mandatory use of the homework template.
Two electric charges q1 = 2 microC and q2 = -2 microC are located at $\vec{r_1}=(1,0,0)m$ and $\vec{r_2}=(0,0,-1)m$ respectively. Calculate the force on q1 in vector form.

$\vec{F_{12}} = \frac {1}{4\pi\epsilon_0}\frac{q_1q_2}{|\vec{r_1}-\vec{r_2}|^3}(\vec{r_1}-\vec{r_2})$

is the formula I am using.

I get an answer of (-0.013, 0, -0.013)N but I don't think this is correct and I have no idea where I messed up.

any ideas? ( I have no numerical solutions to the questions)

Calculate the electric dipole moment of this system (vector form)

I have used P = qD

q = 2x10^-6
d = (1,0,1) which I obtained from using r1-r2

So I just get the charge again multiplied by the vector

Don't think this is correct either.

Calculate the electric fluxes through two spherical Gaussian surfaces centred at the origin with radii R1=0.5m and R2=10m respectively

Now this is confusing. The first sphere doesn't enclose any charge, so q_enclosed is just 0? And the 10m sphere encloses both, but when you find the total charge enclosed, it's 2+ (-2) = 0? so again 0?

Any help appreciated

All looks good to me. What makes you think it's wrong?

How can someone tell you where you messed up if you don't show your work?

$\vec{F_{12}} = \frac {1}{4\pi\epsilon_0}\frac{(2x10^-6)(-2x10^-6)}{\sqrt{2}^3}(1,0,1)$

That is my working

It looks OK. So does your result.