A given system has the equipotential surfaces shown in

Step 1 of 2:

a)

Here, we have to find the direction and magnitude of the electric field.

In the diagram, the equipotentials are given and we always know that the electric field points in a direction of decreasing potential.

So, the direction of the electric field is from V = 30 volt to V = 0 volt.

The magnitude can be found as,

But, first we have to find .

Let’s take the lines of V = 10 volt and V = 0 volt.

These two straight lines are parallel to each other.

Now, the distance between two parallel lines can be found as,

So,

The magnitude of the electric field can be found as,

So, the magnitude of the electric field is 6.25 V/m.