1 Answer
Yes, electric flux can be negative.
Electric flux (\(\Phi_E\)) is calculated using the formula:
\[
\Phi_E = \mathbf{E} \cdot \mathbf{A} = EA \cos(\theta)
\]
Where:
- \(\mathbf{E}\) is the electric field,
- \(\mathbf{A}\) is the area vector (a vector normal to the surface, pointing outward),
- \(\theta\) is the angle between the electric field vector and the area vector.
Now, the flux can be negative if the electric field is pointing in the opposite direction to the area vector. In other words, if the electric field is entering the surface (instead of exiting it), then the flux will be negative. This happens when \(\cos(\theta)\) is negative (i.e., when the angle \(\theta\) is between 90° and 270°).
### Example:
- If the electric field lines are pointing inward through a surface, the flux will be negative.
- If the electric field lines are pointing outward, the flux is positive.
So, the sign of the electric flux depends on the direction of the electric field relative to the surface normal.
Electric flux (\(\Phi_E\)) is calculated using the formula:
\[
\Phi_E = \mathbf{E} \cdot \mathbf{A} = EA \cos(\theta)
\]
Where:
- \(\mathbf{E}\) is the electric field,
- \(\mathbf{A}\) is the area vector (a vector normal to the surface, pointing outward),
- \(\theta\) is the angle between the electric field vector and the area vector.
Now, the flux can be negative if the electric field is pointing in the opposite direction to the area vector. In other words, if the electric field is entering the surface (instead of exiting it), then the flux will be negative. This happens when \(\cos(\theta)\) is negative (i.e., when the angle \(\theta\) is between 90° and 270°).
### Example:
- If the electric field lines are pointing inward through a surface, the flux will be negative.
- If the electric field lines are pointing outward, the flux is positive.
So, the sign of the electric flux depends on the direction of the electric field relative to the surface normal.