Question

Why are electric field lines always emanate perpendicular to a charged surface?

• A. To prevent surface potential
• B. To prevent surface current
• C. To prevent surface polarisation
• D. All of the above

Answer 1

The correct option is B To prevent surface current

If electric field was not perpendicular to the surface, that means it has a component along the surface. Since electric field exerts a force on the charges, now we have a force on the charges along the surface. This force isn't balanced, so it will then move charges around i.e, there would be surface currents. So, to avoid that electric field must emanate perpendicular to surfaces.