Answer
See the graph below.
Work Step by Step
We know that
$$E_s=-\dfrac{dV}{ds}$$
which is the negative slope of the $V$ versus $x$ graph.
We have here 2 stages which are:
- From $x=0$ cm to $x=2$ cm,
$$E_{x1}=-\dfrac{dV}{dx}=-\dfrac{-50- 0}{0.02-0}=\bf 2500\;\rm V/m$$
- From $x=2$ cm to $x=3$ cm,
$$E_{x2}=-\dfrac{dV}{dx}=-\dfrac{50- (-50)}{0.03-0.02}=\bf -10,000\;\rm V/m$$
Now we can draw the $E_x$ versus $x$ graph, as we see below.