Question

Which of the following is not a property of electric lines of force?

• A. Lines of force start from positive charge and terminate at negative charge.
• B. Lines of force always intersect.
• C. The tangent to a line of force at any point gives the direction of the electric field(E) at that point.
• D. The number of lines per unit area, through a plane at right angles to the lines, is proportional to the magnitude of elctric field(E).

Answer 1

The correct option is B Lines of force always intersect.

Properties:

i) Lines of force start from positive charge and terminate at negative charge.

ii) Lines of force never intersect.

iii) The tangent to a line of force at any point gives the direction of the electric field(E) at that point.

iv) The number of lines per unit area, through a plane at right angles to the lines, is proportional to the magnitude of E. This means that, where the lines of force are close together, E is large and where they are far apart, E is small.

v) Each unit positive charge gives rise to $\frac{1}{{\epsilon }_o}$ lines of force in free space. Hence number of lines of force originating from a point charge $q$ is N$=\frac{q}{{\epsilon }_o}$ in free space.