Electrostatic field lines do not form closed loops. Give reason. [ 1 mark question ]

A force is said to be conservative if its work along a trajectory to go from a point Ato a point B is equal to the difference U(A)−U(B) where U is a function called potential energy. This implies that if A=Bthen there is no change in potential energy. This fact is independent of the increase or not of the kinetic energy.

If a conservative force were to form loops, it could provide a non zero net work (because the direction of the force could always be the same as that of the looping trajectory) to go from A and then back to A, while at the same time its conservative character would ensure that this work should be zero; which is a contradiction.

Hence, "conservative force" and "forming loops" are two incompatible properties that cannot be satisfied at the same time.

And electrostatic fields are conservative in nature and hence do not form close loops

B`coz they don`t converge at one point as in case of magnetic field lines. They depend on +ve & -ve charges that can extend infinity in any particular due direction.