What is angle between electric field and equipotential surface?

The angle between electric line of force and equipotential surface is

The angle between electric line of force and equipotential surface is __________ (fill in the blank).

What is the direction of electric field w.r.t. and equipotential surface?

What is angle between the electric field at a point and the equipotential surface passing through the point ?

Relation between field and potential|| Equipotential surface

Draw the electric field lines and equipotential surface for a single positive point charge.