# electrostatic

1. ### Electrostatic force equilibrium

I was thinking that we can equate the electrostatic potential energy and the spring energy (as the force is similar to that of a spring so energy will also be 1/2kx^2 ) but i am not getting the correct ans but by equating the net force on one charge to kr i am getting the correct ans can...
2. ### Engineering How do I find the electric fields for this capacitor?

the image is given here along with some numerical information: Now I know that the formula for the electric field in a capacitor is given as: $$E = \frac{V}{d}$$ which I can use to obtain the three following fomulas: $$E_1 = \frac{V_1}{d}$$ $$E_2 = \frac{V_2}{d}$$ E_3 =...
3. ### Find the electric field inside and outside of a spherical shell superposition

Hi! I need help with this problem. I tried to solve it by saying that it would be the same as the field of a the spherical shell alone plus the field of a point charge -q at A or B. For the field of the spherical shell I got $E_1=\frac{q}{a\pi\epsilon_0 R^2}=\frac{\sigma}{\epsilon_0}$ and for...
4. ### What happens when one of two cocentric spherical shells is grounded?

Hi! I need help with this problem. When the outer shell is grouded, its potential goes to zero, $V_2=0$ and so does it charge, right? $-Q=0$. So the field would be the one produced by the inner shell $E=\frac{Q}{4\pi\epsilon_0 R_1^2}$. When the inner shell is grounded, I think that...
5. ### Understanding Green's second identity and the reciprocity theorem

This is Jackson's 3rd edition 1.12 problem. So, for both $\phi$ and $\phi'$, I started from Green's second identity: $\int_V ( \phi \nabla^2 \phi' - \phi' \nabla^2 \phi )dV = \int_S ( \phi \frac {\partial \phi'} {\partial n} - \phi' \frac {\partial \phi} {\partial n} ) dS$ And...
6. ### I Is my interpretation of this three dimensional improper integral correct?

In Physics/Electrostatics textbook, I am in a situation where we have to find the electric field at a point inside the volume charge distribution. In Cartesian coordinates, we can't do it the usual way because of the integrand singularity. So we use the three dimensional improper integral...
7. ### Potentials (and $\Delta\phi$) of nearby converging bodies

Let $Q$ - charge of one of conductor, $\phi_1$ --- potential of charged conductor, $\phi_2$ --- potential of uncharged conductor. For the charged conductor: $$\phi_1 = D_{11}Q ,$$ for uncharged conductor: $$\phi_2 = D_{21}Q$$

26. ### Potential due to a charged plate using the dipole approximation

1. Homework Statement A plane z=0 is charged with density, changing periodically according to the law: σ = σ° sin(αx) sin (βy) where, σ°, α and β are constants. We have to find the potential of this system of charges. 2. Homework Equations 3. The Attempt at a...
27. ### Capacitance of a sphere

1. Homework Statement Assume a conducting sphere has a radius of 3400km with an electric field of 100 V/m at it's surface. a) Calculate total charge of sphere. b)Calculate potential at the surface using infinity at reference point c) Calculate capacitance of the sphere using the result of a or...
28. ### B Creating a 2-D Electrostatic Field

I've been reading the Feynman lectures in physics. In volume 2 chapter 7: http://www.feynmanlectures.caltech.edu/II_07.html he shows how to mathematically model a 2D electrostatic field. Is it possible to create an experiment that behaves the same way even with the complex variables? Thank you...
29. ### Parallel plate electric fields -- # of electrons transferred

1. Homework Statement An oil droplet is suspended between two horizontal parallel plates with a separation of 0.4 cm. If the potential difference of 320V is applied to the plates, determine the number of electrons transferred to/from the droplet. Given/Known Values mdroplet = 5.2×10-6 kg d =...
30. ### Electric field strength at a point between charges

Find the electric field strength at point B between two charges shown below: Given/Known Values q1 = 4.0×10-6 C r1 = 40 cm = 0.4 m (Distance from q1 to point B) q2 = -1.0×10-6 C r2 = 30 cm = 0.3 m (Distance from q2 to point B) k = 9.0×109 Nm2/C2 Equations Electric Force: FE = (k⋅q1⋅q2)/r2...