electrostatics

Flashcard 1 Q: What is electric field? A:

A: Electric field is the force experienced by a unit positive test charge placed at a point.

Formula of electric field? A:

E=F/q

3 Q: SI unit of electric field?

N/C (or V/m)

What is electric flux?

Electric flux is the measure of the number of electric field lines passing through a surface.

Formula of electric flux?,

SI unit of electric flux?

N·m²/C

State Gauss's law.

Net electric flux through a closed surface equals the enclosed charge divided by �.

Formula of Gauss's law? A

Q enclosed/e

On what does electric flux depend?

Only on the enclosed charge.

Does electric flux depend on the shape of the Gaussian surface?

No

Can charges outside the Gaussian surface contribute to net flux?

No

When can Gauss's law be used to calculate electric field easily?

When there is sufficient symmetry.

Three types of symmetry used in Gauss's law?

Spherical, Cylindrical, Planar.

Electric field due to an infinite plane sheet?

Constant (independent of distance).

Electric field inside a uniformly charged spherical shell?

Zero

Why is the electric field inside a spherical shell zero?

Because the enclosed charge is zero.

Electric field outside a spherical shell?

Same as a point charge.

Electric field inside a uniformly charged solid sphere?

Increases linearly with distance from the center �.

Where is the electric field maximum in a uniformly charged solid sphere?

At the surface.

Charge outside a Gaussian surface. Net flux?

Zero.

Why is the net flux zero when the charge is outside?

Equal field lines enter and leave the closed surface, so the net flux cancels.