Which of the following is NOT the property of electric field lines?

The correct answer is Option (3) → They form closed loops.

The electrostatic field is conservative: the work done in taking a charge round any closed path is zero. If a field line formed a closed loop, a charge carried along it would have work done on it all the way round, so electrostatic field lines never form closed loops.

Option (1) They start from positive charges and end at negative charges. — A property. Field lines begin on positive charges and end on negative charges (or at infinity).

Option (2) They can never cross each other. — A property. If two lines crossed, the field at that point would have two directions, which is impossible.

Option (3) They form closed loops. — Not a property. Electrostatic field lines do not form closed loops, as shown above; closed loops are a property of magnetic field lines.

Option (4) They are continuous curves in a charge-free region. — A property. In a region without charges the field lines are continuous curves without breaks.

NCERT (2026-27):
Electric Field Lines – “… The field lines follow some important general properties: (i) Field lines start from positive charges and end at negative charges. … (ii) In a charge-free region, electric field lines can be taken to be continuous curves without any breaks. (iii) Two field lines can never cross each other. … (iv) Electrostatic field lines do not form any closed loops. This follows from the conservative nature of electric field (Chapter 2).”