Electrostatics - Coulomb's Law

Join the discussion
Registration is free. Start your own thread to ask a follow-up.
Sign up Log in
3 replies · 3K views
jinksys
Messages
122
Reaction score
0
I'm doing example 2.1 in Griffith's Electrodynamics book. Can someone explain where the cos(theta) comes from in the formula for dE? The formula is on the first image: Here.
 
Physics news on Phys.org

Discussion

SOLVED:

I see what's going on. If you add the r_hat vectors you end up with 2(z/r)z_hat. z/r=cos(theta). So we end up with 2cos(theta)z_hat.
 
that looks so hard. are you supposed to figure out that formula all by yourself
 
bael said:
that looks so hard. are you supposed to figure out that formula all by yourself

No, the formula is given to you in a general form.
 

Similar threads

Undergrad Coulomb's law taken to the extreme
  • neobaud
  • · Replies 44 ·
  • Electromagnetism
2
Replies
44
Undergrad Coulomb's law for steady currents
  • Kashmir
  • · Replies 10 ·
  • Electromagnetism
Replies
10
Undergrad Coulomb's law, electrostatics?
  • Jurtinus
  • · Replies 42 ·
  • Electromagnetism
2
Replies
42
Undergrad Does Coulomb’s law change at relativistic speeds?
  • Bastion
  • · Replies 17 ·
  • Electromagnetism
Replies
17
High School What's "Coulomb's law but ##F## converges as ##r\rightarrow##0" called?
  • not my name
  • · Replies 8 ·
  • Electromagnetism
Replies
8
Undergrad Why Jackson and Griffiths use different notation for Coulomb's law
  • Selectron09
  • · Replies 4 ·
  • Electromagnetism
Replies
4
Graduate Test charge velocity in Coulomb's Law
  • akhila_k
  • · Replies 3 ·
  • Electromagnetism
Replies
3
Undergrad How does permittivity in Coulomb's law work?
  • Efeguleroglu
  • · Replies 5 ·
  • Electromagnetism
Replies
5
Undergrad Is Coulomb's law valid in a non-inertial frame?
  • xxxyyy
  • · Replies 2 ·
  • Electromagnetism
Replies
2
Graduate The relationship of one of Maxwell's equations to Coulomb's Law
  • MaestroBach
  • · Replies 3 ·
  • Electromagnetism
Replies
3