Electric Flux Formula

The electric flux through a planar area is defined as the electric field times the component of the area perpendicular to the field.

Electric flux = Electric field * Area * (angle between the planar area and the electric flux)

The equation is:

Φ = E A cos(θ)

Where:

Φ: Electric Flux

A: Area

E: Electric field

θ: angle between a perpendicular vector to the area and the electric field

Electric Flux Formula Questions:

1) A planar surface has an area of 1 m², if an electric field crosses with an angle of 30° to it, and has E= 2 V/m. What is the electric flux?

Answer:

From the formula of the electric flux,

Φ = E A cos(θ) = 2 V/m * 1 m² * cos(30°)

Φ = 1 V m

2) A planar surface has an area of 0.25 cm², if an electric field crosses perpendicular to it, and has E= 2 V/m. What is the electric flux?

Answer:

From the formula of the electric flux,

Φ = E A cos(θ) = 2 V/m * 2.5 * 10^(-5) m² * cos(0°)

Φ = 5*10^(-5) V m