Question

In the context of conductors in electrostatic equilibrium, the relationship between electric field and the conductor's surface is:

• A. Electric field is parallel to the surface
• B. Electric field is perpendicular to the surface
• C. Electric field is tangential to the surface
• D. Electric field is zero on the surface

Hint:

Remember that electric field lines point from higher potential to lower potential and are always perpendicular to equipotential lines/surfaces. Since a conductor's surface is an equipotential, the E-field lines must emerge from it at a right angle.

Answer 1

The Correct Option is B

Step 1: Recall the properties of a conductor in electrostatic equilibrium. One of the key properties is that the electric potential is constant throughout the entire conductor, including its surface. This means the surface of a conductor is an equipotential surface.
Step 2: Relate electric field lines to equipotential surfaces. Electric field lines are always perpendicular to equipotential surfaces. If there were a component of the electric field parallel (tangential) to the surface, it would exert a force on the charges on the surface and cause them to move.
Step 3: Apply the condition of electrostatic equilibrium. "Electrostatic equilibrium" means that the charges are no longer moving. For the charges to be stationary, there must be no net force on them parallel to the surface. This implies that the tangential component of the electric field must be zero.
Step 4: Conclude the relationship. If the tangential component of the electric field is zero, the electric field vector at the surface must be entirely perpendicular to the surface. Note that the field is not zero on the surface unless there is no charge on the conductor at all.