Understanding and Solving Electrostatics Problems: Tips and Techniques

In summary, The conversation discusses identifying electrostatic fields and determining the charge density that creates them. The equations ∇.E=ρ/ε and ∇xE=-dB/dt are mentioned as ways to approach the problem, with the latter being used when the field is not electrostatic. The equation del dot D = rho is also mentioned as a way to find the charge density. The conversation concludes with the possibility of a time-varying E0 adding complexity to the problem.
  • #1
Murgs2012
11
0

Homework Statement


exams.JPG


Any ideas on the way to approach them problems would be appreciated really.



Homework Equations



Assuming it has something to do with ∇.E=ρ/ε or ∫E.ds=Q/ε to see if the divergence of the E fields given satisfy them conditions, if not use ∇xE=-dB/dt or ∫E.dl=-d/dt∫(Bds)

The Attempt at a Solution


no idea how to approach it.
 
Physics news on Phys.org
  • #2
You are on the right way track with
[itex]\vec{\nabla}\times\vec{E} =-\frac{\partial\vec{B}}{\partial t}[/itex]
For an electrostatic configuration there are no moving charges and hence no magnetic field. Knowing this, what will this equation become then?
 
  • Like
Likes 1 person
  • #3
So for that equation in an electrostatic field ∇xE=0, and that would be the way to determine if it's electrostatic or not?
If it's electrostatic would you then use Gauss' law ∇.E=ρ/ε to find the charge density that creates this field.

If it's not electrostatic would the non zero result found for ∇xE= -dB/dt, so integrate with respect to time to determine the magnetic field that causes the electric field?
 
  • #4
How about del dot D = rho?
(D = epsilon E).
 
  • #5
That's how we'd find the charge density Rho isn't it? But that's only part of the question, it was how to know if it was an electrostatic field that was annoying me
 
  • #6
Murgs2012 said:
That's how we'd find the charge density Rho isn't it? But that's only part of the question, it was how to know if it was an electrostatic field that was annoying me

OK, I guess I assumed E0 was a constant. Then E is not a function of time and so must be electrostatic if it obeys the Poisson equation. Same for part c.

If E0 can be time-varying then it's more complicated.
 

What is electrostatics?

Electrostatics is a branch of physics that studies the effects of stationary electric charges and their interactions with other objects and fields.

What is an electric charge?

An electric charge is a fundamental property of matter that can either be positive or negative. It is responsible for the attraction and repulsion between objects.

How is electrostatics different from electromagnetism?

Electrostatics deals with stationary charges, while electromagnetism deals with moving charges and the interactions between electric and magnetic fields.

What is the unit of electric charge?

The unit of electric charge is the coulomb (C). It is defined as the amount of charge that passes through a point in one second when there is a constant current of one ampere (A).

What is the principle of electric charge conservation?

The principle of electric charge conservation states that the total electric charge in a closed system remains constant. This means that charges can neither be created nor destroyed, only transferred from one object to another.

Similar threads

  • Introductory Physics Homework Help
Replies
13
Views
496
  • Introductory Physics Homework Help
Replies
15
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
3K
  • Introductory Physics Homework Help
Replies
11
Views
597
  • Introductory Physics Homework Help
Replies
8
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
16
Views
3K
Back
Top