An equipotential surface must be

A. tangent to the electric field at every point.
B. perpendicular to the electric field at every point.
C. parallel to the electric field at every point.
D. equal to the inverse of the electric field at every point.
E. equal to the electric field at every point.

An equipotential surface must be perpendicular to the electric field at every point. The correct option is B.

Explanation: Equipotential surface is any surface over which the potential difference is constant. Examples include:

-The surface of a conductor in electrostatic field.

- surface of a liquid in equilibrium.

Equipotential surface are perpendicular to the electric field at every point because components of electric field intensity along the surface is zero ( this is because no work is done while moving a charge from one point to another on an equipotential surface).

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