Slides for the Discussion of Electric Flux and Gauss's Law for Grade 12 Physics 1 in the Philippines.

3. Electric Flux &
Gauss’ Law

4. Electric Flux
• Consider an electric field that is
uniform in both magnitude and
direction.
• The field lines penetrate a rectangle
surface area A, whose plane is
oriented perpendicular to the field.

5. Electric Flux
• Therefore, the total number of lines
penetrating the surface is
proportional to the product of E and A
(E x A)
• This product of the magnitude of the
electric field E and surface area A, is
what we call Electric Flux.
ΦE= EA

6. Electric Flux
• The electric flux (Φ) is
proportional to the number of
electric field lines penetrating
some surface.
ΦE= EA
↑E → ↑ΦE, ↑A → ↑ΦE , and ↑E↑A → ↑ΦE

7. Electric Flux
• If the surface under
consideration is not
perpendicular to the field, we use
the formula:
Where: E - Electric Field Lines
A - Surface Area

8. Electric Flux
θ is the angle between
and

9. Electric Flux
A flat surface in a uniform electric field. The electric flux
through the surface equals the scalar product of the electric
field area.

10. Electric Flux

11. Electric Flux
Flux through a surface of
fixed area has a maximum
value when the surface is
perpendicular to the field.
Flux is less than maximum
but more than minimum
when the surface is tilted
with some angle.
Flux is zero when the
surface is parallel to the
field.

12. Flux of a Non-Uniform
Electric Field
If the electric field is not
uniform but varies from point
to point over the area A, then
we divide A into many small
elements dA.

13. Flux of a Non-Uniform
Electric Field

14. Flux through a closed
surface A closed surface is defined as
the surface that divides space
into an inside and outside
region so that one cannot
move from one region to the
other without crossing the
surface.

15. Flux through a closed
surface

16. Flux through a closed
surface