Practice question · Multiple choice
An isolated conductor is brought into equilibrium after having charge added to it. Because the whole body forms an equipotential, what must follow for the electrostatic forces acting on the surface charges?
Hints
- Does zero tangential field across a surface imply zero perpendicular field?
- What outward mechanical effect arises from mutual surface charge repulsion?
Show the answer
B. A normal outward force acts on them without lateral drift
Why
Equipotential surfaces forbid tangential fields, preventing lateral drift along the conductor. However, the surface charge experiences an outward normal electrostatic pressure proportional to the square of surface charge density, meaning the local normal force does not vanish.
Practise Conductors and Capacitance
The app has 5 more questions on this lesson, and keeps your place in the course. Physics II is free to start.
More questions on Conductors and Capacitance
- Why must the electric field vanish inside a conductor in electrostatic equilibrium?
- A parallel-plate capacitor has plate area 0.02 m², separation 1.0 mm, and vacuum between the plates. Compute…
- The capacitance of a capacitor increases when more charge is placed on its plates.
- Which are true of a conductor in electrostatic equilibrium?
- Match each capacitor arrangement to the quantity its elements share and the resulting combination.
- Arrange these consequences of electrostatic equilibrium in the order they logically follow from one another.