Electric Field Lines for a System of Two Charges

When dealing with a system of two charges, it is important to draw electric field lines to visualize the direction and strength of the electric field. The electric field lines always start from positive charges and end at negative charges.

Case i) q1q2>0; q1>q2>0

When the product of the two charges is positive and the magnitude of the first charge is greater than the magnitude of the second charge, the electric field lines will look like:

- The electric field lines around q1 will be more dense and stronger, indicating a stronger electric field.
- The electric field lines around q2 will be less dense and weaker, indicating a weaker electric field.

Case ii) q1q2|-q2||-q2|

When the product of the two charges is negative and the magnitude of the second charge is greater than the magnitude of the first charge, the electric field lines will look like:

- The electric field lines will start from q2 and end at q1, as the negative charge always attracts the positive charge.
- The electric field lines around q2 will be more dense and stronger, indicating a stronger electric field.
- The electric field lines around q1 will be less dense and weaker, indicating a weaker electric field.

In both cases, it is important to note that the electric field lines never cross each other. This is because the electric field has a unique direction and strength at each point in space, and crossing lines would indicate two different directions or strengths at the same point.

Overall, drawing electric field lines is a useful tool in understanding the behavior of electric charges and the electric field they create.