**Examples
for electric field and equipotential lines**

Example #1

Problem:

Is the electric
field zero at *a,b,c,d*?

yes,no,no,no

Is the electric
potential zero at *a,b,c,d*?

yes,yes,yes,no

Example #2

Problem:

What is the
magnitude and direction of the electric field at *a*?

Solution:

The electric field is given by:

where is
1000 volts and is the distance between the two lines,
which we measure to be 1.4 *cm*. Therefore E=1000/.014.

E =
7.1E4 (*V*)