Question

Electric lines of force about a negative point charge are:
A. circular anti-clockwise
B. circular clockwise
C. radial, inwards
D. radial, outwards

Answer 1

Use the concept that the electric lines of force always originate from a positive charge and terminate on a negative charge. Use this concept and determine what should be the path of the electric lines of force for a negative charge from the all four given options.

Complete answer:
We know that the electric lines of force about a single point charge are never circular.Hence, the options A and B are incorrect.The direction of the electric lines of force about a point charge is always radial and towards the charge or away from the charge depending on whether the charge is positive or negative.

As the electric lines of force always originate from the positive charge, the electric lines of force cannot be outward from the negative point charge. Hence, the option D is incorrect.

Now, the electric lines of force always terminate on the negative point charge. Hence, the electric lines of force should be radial and towards the negative point charge.

Hence, the correct option is C.

Note: The students may also give the explanation for the same question in another way. The direction of the electric lines of force is the direction of the electric field which is given by the electrostatic force on the charge. The direction of this electrostatic force is outward from the charge for the positive charge and towards the charge for a negative charge. Hence, the direction of electric field lines is radial and inward for a negative charge.