Question 34

Identify the correct statements :
A. Electrostatic field lines form closed loops .
B. The eleclric field lines point radially outward when charge is greater than zero.
C. The Gauss - Law is valid only for inverse - square force.
D. The workdone in moving a charged particle in a static eleclric field around a closed path is zero.
E. The motion of a particle under Coulomb's force must take place in a plane.
Choose the correct answer from the options given below:

We need to evaluate each statement about electrostatics and identify the correct ones.

Statement A: "Electrostatic field lines form closed loops."
Electrostatic field lines originate from positive charges and terminate at negative charges. They do not form closed loops. Closed loops are characteristic of magnetic field lines. Hence, statement A is false.

Statement B: "The electric field lines point radially outward when charge is greater than zero."
For a positive point charge (charge > 0), electric field lines are directed radially outward. For a negative charge, they point inward. The statement specifies charge greater than zero, so it is true. Hence, statement B is true.

Statement C: "The Gauss's Law is valid only for inverse-square force."
Gauss's Law states that the flux through a closed surface is proportional to the enclosed charge. This law relies on the inverse-square nature of the electrostatic force (Coulomb's law). If the force were not inverse-square (e.g., proportional to $$1/r^3$$), Gauss's Law would not hold. Therefore, Gauss's Law is valid specifically for inverse-square forces. Hence, statement C is true.

Statement D: "The work done in moving a charged particle in a static electric field around a closed path is zero."
The electrostatic field is conservative. In a conservative field, the work done around any closed path is zero. Hence, statement D is true.

Statement E: "The motion of a particle under Coulomb's force must take place in a plane."
Coulomb's force is a central force (directed along the line joining the particles). For motion under a central force, the angular momentum is conserved, and the motion is confined to a plane perpendicular to the angular momentum vector. Hence, statement E is true.

Summary of evaluations:
- A: False
- B: True
- C: True
- D: True
- E: True

The correct statements are B, C, D, and E.

Now, comparing with the options:
- Option A: A, C, E Only → Incorrect (includes false statement A)
- Option B: A, B, D, E Only → Incorrect (includes false statement A)
- Option C: B, C, D, E Only → Correct
- Option D: A, B, C, D Only → Incorrect (includes false statement A)

Therefore, the correct answer is Option C.

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