Question

Draw the electric field lines due to (i) an isolated positive charge
(ii) an isolated negative charge
(iii) an electric dipole
(iv) Two positive charges

Answer 1

Answer:

ii) an isolated negative charge

Answer 2

Answer:  Electric field due to a point charge:

Vector form: The electric field vector at a point P due to a point charge q at a position r from P is given by

Explanation:

E = k q r/r^3

where k is the Coulomb constant (8.99 x 10^9 Nm^2/C^2) and r is the radial distance from P to q.

SI unit of electric field: The SI unit of electric field is N/C (Newtons per Coulomb).

(a) An isolated positive charge: Electric field lines due to an isolated positive charge will radiate outwards from the charge in all directions.

(b) An isolated negative charge: Electric field lines due to an isolated negative charge will radiate inwards towards the charge in all directions.

(c) An electric dipole: Electric field lines due to an electric dipole will be radial, originating from the positive charge and terminating on the negative charge.