electric field r ˆ q - physics main | physics
TRANSCRIPT
Electric Field r̂12
!FQq =
1
4!"0
Qq!r12
2r̂12Force on q by Q
q
Defini3on of Electric field: at this point is
!E =
"FQq
q=
1
4!"0
Q!r12
2r̂12
Q !r12
More complex example
x
y
L
Uniformly charged rod: total charge Q
a
Lecture 3
How do you solve this?
x
y
L a
We could solve this:
Show on the doc cam: step by step:
x
y
a
Define amount of charge on this small segment: dq
L+a
Length of this segment : dx
Define electric field exerted by this segment: dE dE! = E
total
But how do we do this integra3on?
Total charge = Q : charge per length : Q/L
dq =
Q
Ldx
x
y
Infinitely long uniformly charged rod
d
Charge per unit length: λ
Example 2
Electric Field Lines
Electric Flux
! = EA
Flux: N m2/C
What if the plane in ques3on is 3lted?
Gauss’s Law
Example: Point charge q
Another Example:
More Drawing example
Example: Uniformly charged sphere
Example: uniformly charged infinite line charge