 |
| Electric Field Lines |
|
| Michael Faraday (1791 - 1867) introduced the idea of lines of forces. |
| |
| They are nothing but a way of pictorially mapping the electric field around a configuration of charges. It is the curve drawn in such a way that the tangent to it at each point is in the direction of the net field at the point. An arrow on the lines of force is a must to indicate the direction of the electric field. |
| |
| Let us see the nature of the lines of force in the following cases : |
| |
| Case 1: |
| |
| If it is a positively charged body, then the electric lines of force are directed away from the body. |
| |
 |
| |
| Case 2: |
| |
| If the body is negatively charged, then the lines of force are directed towards the body. |
| |
 |
| |
| Case 3: |
| |
| When two positively charged bodies are involved, the electric lines of force gives a vivid picture of mutual repulsion. |
| |
 |
| |
| Like Charges (q |
|
| q |
|
| > 0) |
| |
| Case 4: |
| |
| In the case of two equal and opposite charges, the lines of force clearly shows mutual attraction, the lines move from +ve to -ve. |
| |
 |
| |
| Unlike Charges (q |
|
| q |
|
| < 0) |
| |
| |
| |
| The figure below shows the lines of force due to an infinitely large sheet of positive. |
| |
 |
| |
|
| |
| The lines of force or field lines |
| |
| 1) start from positive charges and end at negative charges. In the case of a single charge, they may start or end at infinity. |
| |
| 2) two field lines can never intersect each other. |
| |
| 3) contract longitudinally. |
| |
| 4) exert lateral pressure on one another. |
| |
| 5) are perpendicular to the surface of a charged conductor. |
| |
| 6) do not pass though the conductor. |
| |
