Question

There are two line charges each of length "L" having the same
line charge density with one kept along the y-axis from (0,0)
to (0,a) and the other parallel to the former from (2a,0) to
(2a,a). Evaluate the electric field due to both these line charges
at the point (a,0)​

Answer 1

Answer:

The charge distributions we have seen so far have been discrete: made up of individual point particles. This is in contrast with a continuous charge distribution, which has at least one nonzero dimension. If a charge distribution is continuous rather than discrete, we can generalize the definition of the electric field. We simply divide the charge into infinitesimal pieces and treat each piece as a point charge.

Explanation:

Note that because charge is quantized, there is no such thing as a “truly” continuous charge distribution. However, in most practical cases, the total charge creating the field involves such a huge number of discrete charges that we can safely ignore the discrete nature of the charge and consider it to be continuous. This is exactly the kind of approximation we make when we deal with a bucket of water as a continuous fluid, rather than a collection of {\text{H}}_{2}\text{O} molecules.