Question

Which of the following statements is not true about electric field lines?
A. Electric field lines start from positive charge and end on negative charge.
B. Two electric fields can never cross each other.
C. Electric field lines do not form any closed loops.
D. Electric field lines cannot be taken as continuous curves.

Answer 1

Hint: Electric field lines are just conceptual entities that we assume just to understand the behavior of charge properly. There is nothing like emerging out of charge and getting inside. Michael Faraday introduced the concept of field lines to understand the behavior of charge. Physically, it’s not present in reality.

Complete step-by-step answer:
We will see the solution part wise.
A. Electric field starts from positive charge and ends on negative charge. The statement is true because while assuming the electric field lines, it was a postulate that it should start from positive charge and end on negative charge.

B. Two electric field lines can never intersect each other. The statement is true because tangent in the path of electric field lines gives us the direction of the electric field at that point. In case the lines cut each other, it means that there will be 2 directions on the electric field, which is impossible.

C. Electric field lines do not form any closed loops. The statement is true because the electric field lines start from positive charge and end on negative charge. Since the starting and ending point of the electric field lines is different, a loop can never be closed.

D. Electric field lines cannot be taken as continuous curves. This statement is wrong because if it were not a continuous curve, it means that at some point in space, where the field is not present, the force on another charge at that point is zero and further going beyond that point, it will suddenly start experiencing a field.

Hence option D is the required answer.

Note: These are the basics while dealing with electric field questions so these must be kept in mind. For closed loops, it’s only possible when the material of emitting and absorbing is the same. Magnets are good examples of this statement. Since monopoles don’t exist, hence it is always present in pairs and always closed loops are formed.