Test: Electric Field & Electric Field Lines - JEE MCQ

The zone near a charge where its attraction or repulsion force works, is known as the electric field of that charge. Theoretically, it is up to infinite but practically it has limitations. If a unit positive charge is kept in that field, it will undergo some force which is known as electric field intensity at that point.

If a unit positive charge is kept near a negative charge, the unit positive charge will be attracted towards the negative charge. That means the electric field is towards the negative charge. But in case of positive charge, the field is directed away from the charge.

According to Gauss’s law, if there is no charge inside a closed surface, the field inside the closed surface will always be zero. We know the charge is distributed on the outer surface of a conducting hollow sphere because the charges want to maintain maximum distance among them due to repulsion. So there is no charge inside the sphere and hence no electric field.

There is gravitational field on earth, so if we hang the two same charges there will be an interaction of vertical gravitational field and horizontal electric field. The system will achieve equilibrium by creating a certain angle between the threads and hence the vertical and horizontal components of forces will balance. But in space, there is no gravity. So the charges will be at 180-degree separation.

A scalar quantity is a quantity with magnitude only but no direction. But a vector quantity possesses both magnitude and direction. An electric field has a very specific direction (away from a positive charge or towards a negative charge). Hence electric field is a vector quantity. Moreover, we have to use a vector addition for adding two electric fields.

Electric field lines always converge at a negative charge and diverge from the positive charge. If a unit positive charge is kept in an electric field, the path of motion of that charge is known as field lines. Now we know that a positive charge is always pushed away by another positive charge. Thus we can find the direction of field lines near a positive charge.

We know that the electric field at a point is directed towards the tangent of electric field lines at that point. Now if two field lines intersect at a point, two tangents can be drawn at that point. That means at a particular point there would be two separate directions of the electric field which is impossible. So, we can conclude that two electric field lines never intersect each other.

The electric field between two uniformly charged plates is uniform. Electric field lines in the uniform electric field are parallel to each other and uniformly distributed. This phenomenon is observed in most of the parts between the plates. But in the two extreme ends, the field line fringes out due to the non-uniform electric field.

Electric lines of force are always diverging from positive charge and they converge at a negative charge. Besides, they repel each other because of repulsion between two similar charges. They remain parallel to each other in the uniform field but may divert in case of a non-uniform field. These lines are continuously stretched between two opposite charges and always try to maintain minimum length.

Electrical neutral point is a point in between two positive and negative charges, where the electric field intensity is zero. It means that no lines of force pass through that point because electric field lines are the measure of field intensity i.e. more lines mean more field intensity. The lines never converge or diverge neither they coincide at that point.