Which among the curves shown in Fig. 1.35 cannot possibly represent electrostatic field lines?
Electrostatic field lines have some properties and characteristics, which should be taken into account while drawing Electrostatic field lines, the Characteristic of electrostatic field lines are :-
1. They start from a positively charged body and end at a negatively charged body.
2. Tangent to the electrostatic field line at any point gives the direction of the electric intensity at that point.
3. Electrostatic field lines cannot intersect each other.
4. The electrostatic field lines are always normal to the surface of a conductor. There is no component of the electric filed intensity parallel to the surface of the conductor.
5. Electrostatic field lines do not form any closed loops.
These properties and characteristics must be taken into account while drawing electrostatic field lines, if any of these are violated then the following representation will be incorrect.
(a)
| We know electrostatic field lines are always normal to the surface of conductor, but here Lines are not always perpendicular to the surface of conductor as shown in the Figure i.e. this is incorrect representation of Electrostatic Field lines. |
(b)
| We Know that, They starts from a positively charged body and end at a negatively charged body. i.e. they are directed outwards emerging from a Positively charged body, and directed inwards ending at a negatively charged body. But here the Electrostatic field lines are starting from a negative charge and end ending at a positive charge as shown in the figure this is not possible i.e. this representation of electrostatic field lines is incorrect. |
(c)
| This is the correct representation of electrostatic field lines when two positive charges are kept in close to each other, Field lines not forming any closed loops, not intersecting, starting from positive charge and directed outwards. |
(d)
| We know Electrostatic field lines cannot intersect each other, because If they intersect, the field at the point of intersection will not have a unique direction, since tangent to electrostatic field lines shows the direction of field, at the point of intersection two tangents can be drawn, showing two directions at same point which is not possible. In this case the Electrostatic field lines are intersecting as shown in the figure this is not possible i.e. this representation of electrostatic field lines is incorrect. |
(e)
| We Know Electrostatic field lines do not form any closed loops, because they are conservative in nature, but in this case they are forming closed loops as shown in the figure this is not possible i.e. this representation of electrostatic field lines is incorrect. |
Hence, only (c) is the correct representation of electrostatic field lines and (a),(b),(d),(e) are incorrect representations of electrostatic field lines .