Electric Field Lines Properties: Intersection Rule
Electric field lines are used to represent the electric field in space. Understanding their properties is crucial for electrostatics.
- Property: Uniqueness of Field Direction
The electric field vector at any given point in space must point in only one direction. This is a fundamental principle. - Correct Statement Analysis
Option 4 states "They never intersect". This is correct because if two electric field lines were to intersect at a point, it would imply that the electric field has two different directions at that single point. This contradicts the fundamental nature of vector fields, where the field direction must be unique at every point. - Incorrect Statement Analysis
- Option 1: "They can form closed loops" is incorrect for static electric fields. Closed loops typically occur in magnetic fields (e.g., due to changing magnetic flux).
- Option 2: "They start on negative charges and end on positive charges" is incorrect. Electric field lines originate on positive charges and terminate on negative charges.
- Option 3: "They are always straight lines" is incorrect. Field lines are straight only in uniform electric fields or radially from a point charge. They can be curved in non-uniform fields.
Therefore, the only correct statement regarding electric field lines among the choices is that they never intersect.
Important Questions from Electric Charge
Which of the following expressions correctly represents the SI unit of electric charge, the Coulomb ($C$), in terms of other fundamental or derived SI units?
- Suppose every second 1016 electrons come out of a body and move to another body, then the time is required to get a total charge of 3.2 C on the other body is:
- An object is found to have a net negative charge of $-5 \text{ nC}$. How many excess electrons are present on the object? (Given: elementary charge $e = 1.6 \times 10^{-19} \text{ C}$)
- A metallic sphere, initially possessing a positive electric potential relative to the Earth, is connected to the Earth by a conducting wire. Which of the following accurately describes the primary charge movement that occurs until equilibrium is reached?
Two point charges, $Q_1 = +3 \mu C$ and $Q_2 = -8 \mu C$, are placed at a certain distance apart. They attract each other with a force of $48 N$. If each charge is given an additional charge of $+6 \mu C$, what will be the magnitude and nature of the new force between them?
