Which statement is true for electric field lines?
field lines should always be parallel to the equipotential lines.
field lines should always be perpendicular to the equipotential lines.
field lines should always be parallel to each other.
field lines should always be crossing each other.
field lines should always be perpendicular to each other.

Field lines should always be perpendicular to the equipotential lines.

Explanation:

As we know that equipotential lines are the locus of all points at which potential will remain constant.

So here we can say by the relation of potential difference and electric field is given as

now if potential is constant or not changing then we will say that change in potential is zero

so here if electric field is perpendicular to the equipotential lines then in that case the potential will remain constant.

so correct answer will be

Field lines should always be perpendicular to the equipotential lines.

true tan speed = ang vel x radius