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.

 

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Gauss’s Law

 

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