Question

Electric flux at a point in an electric field is

• A. positive
• B. negative
• C. zero
• D. none of these

Hint:

Consider the relationship between electric flux and the orientation of the surface with respect to the electric field lines. 

Answer 1

The Correct Option is C

The correct answer is Option C) zero

As the area of a point is zero, \(\therefore \, \phi =E (ds) \cos \theta = E \cos \theta \times 0\) = Zero

Electric flux is ∮E⋅da (where da refers to the area element). As we know, the point area is zero 

Therefore, the flux associated with a point is zero

Discover More From the Chapter: Electric Charges and Fields

 

Answer 2

The correct answer is Option C) zero

Real Life Applications

Electric flux is used in real life as 
- Gauss's law states that the electric flux through a closed surface is equal to the charge enclosed by the surface divided by the permittivity of free space. This law can be used to calculate the electric field of a charged object. 
- Electric field sensors are devices that can measure the electric field. These sensors are used in a variety of applications, such as industrial safety, medical diagnostics, and environmental monitoring.

Question can also be asked as

1. What is electric flux?
2. What is the relationship between electric flux and electric field?
3. What are the conditions for electric flux to be zero?

Answer 3

The correct answer is Option C) zero

Electric flux is a fundamental concept in electromagnetism. It helps us understand the flow of electric field lines through a given surface. 

• In certain cases, the electric flux at a point in an electric field can be zero.
• Electric flux, denoted by Φ, is a measure of the number of electric field lines passing through a given area.
• It is defined as the dot product of the electric field vector and the area vector of the surface over which the flux is being calculated.

Mathematically, it can be expressed as Φ = E * A * cos(θ),

• where Φ represents the electric flux,
• E is the electric field,
• A is the area vector,
• θ is the angle between the electric field and the surface normal.

Electric Flux and Zero Flux:

Under certain conditions, the electric flux at a point in an electric field can indeed be zero. 

1. If the electric field and the surface exhibit a high degree of symmetry, the electric flux may be zero. 

For example, consider a point charge surrounded by a spherical surface. The electric field lines will be radial and uniformly distributed. 

In this case, the electric flux through the spherical surface will be zero, as the electric field lines will enter and exit the surface with equal strength.

2. When dealing with closed surfaces, such as a Gaussian surface, the electric flux can be zero if the net charge enclosed within the surface is zero. 

Gauss's law states that the electric flux through a closed surface is proportional to the net charge enclosed by that surface. 

If the net charge is zero, the electric flux will be zero.

Symmetry plays a crucial role in determining whether the electric flux will cancel out or not. Additionally, for closed surfaces, if the net charge enclosed within the surface is zero, the electric flux through that surface will be zero.