# Electric Flux-

Electric flux is defined as-

 The total number of electric field lines passing perpendicularly through a given area held inside an electric field is called as electric flux. It is denoted by Φ.

## Factors Affecting Electric Flux-

The electric flux through an area depends upon the following factors-

### 1. Electric Field Strength-

#### Electric Flux ∝ Strength of Electric Field

• The electric flux through an area increases with the increase in strength of the electric field and vice-versa.
• This is because stronger the electric field, closer are the electric field lines and therefore more number of electric field lines passes through the area.

### 2. Size of the Area-

#### Electric Flux ∝ Size of the Area

• The electric flux through an area increases with the increase in its size and vice-versa.
• This is because greater the size of area, more number of electric field lines passes through the area.

### 3. Angle Between Electric Field & Area Vector-

#### Electric Flux ∝ Cosine of Angle Between E and A

• This is because the electric flux through an area decreases with the increase in angle between Electric Field and Area Vector and vice-versa.

## Electric Flux Formula-

On combining the above factors, we get the following formula for calculating electric flux through a given area-

Here,

• E = Electric Field Intensity
• A = Magnitude or size of the Area
• θ = Angle between Electric Field and Area Vector

The above formula can be expressed in terms of dot product of two vectors as-

## Characteristics of Electric Flux-

It is important to note the following characteristics of electric flux-

• It is a scalar quantity.
• The SI unit of electric flux is NC-1m2.
• The dimensional formula of electric flux is [M1L3T-3A-1].
• The electric flux through an area can be positive, negative or zero.