Question

Electric field lines are shown between two charges A and B kept near to each other. Identify the charges A and B, respectively?
(A) Positive, positive
(B) Negative, negative
(C) Positive, negative
(D) Negative, positive

Answer 1

The electric field lines are the lines that are drawn in an imaginary way that specifies the direction of its flow between the charges. The close lines between the charges specify the intensity of the electric field at that point. These lines provide the visual idea of the electric field and its orientation.

Complete answer
The electric field is introduced first by the scientist Michael Faraday. These lines do not cross each other and are perpendicular to the charged surface. The electric field lines begin from the positive charge and come on the way to the negative charge. From the given diagram, it is clear that the field lines originate in point B and move away from it. Hence it must be a positive charge. Even though considering point A, all the field lines come towards it from point A, hence it must be the electron.
Thus the option (D) negative, positive.

Additional information
We also have some other properties of electric field lines. The field lines are all the time perpendicular to the surface charge. The number of field lines is directly proportional to the magnitude of the charge. If we have a single positive charge, the field lines end at infinity and if we have a single negative charge, the field lines start at infinity.

Note
If the charge has more magnitude, then the number of the field lines that it has will also be more. Remember that the electric field lines begin from the positive charge and it ends on the negative charge. If both the similar charges are placed near to each other, then the field lines will be away from each other.