Advertisements
Advertisements
Question
Why must electrostatic field be normal to the surface at every point of a charged conductor?
Advertisements
Solution
In case of conductors the charge is present only on the outer surface. Inside the conductor the field is zero. And at the surface it has to be normal. If it is not normal to the surface, then it would have some non-zero component along the surface. The free charges on the surface would then experience a force and start moving. In a static situation, electrostatic field should not have tangential component, which in turn implies that the surface of a charged conductor must be normal to the surface at every point. If a conductor has no surface charge, then the field is zero.
APPEARS IN
RELATED QUESTIONS
Three point charges, + Q + 2Q and – 3Q are placed at the vertices of an equilateral triangle ABC of side l. If these charges are displaced to the mid-point A1, B1 and C1, respectively, find the amount of the work done in shifting the charges to the new locations.

Guess a possible reason why water has a much greater dielectric constant (= 80) than say, mica (= 6).
Obtain an expression for an intensity of electric field at a point at the end of position, i.e., the axial position of an electric dipole.
x
Two point charges of 10C each are kept at a distance of 3m in the vacuum. Calculate their electrostatic potential energy.
The electrostatic potential energy of two-point charges, 1 µC each, placed 1 meter apart in the air is:
A body moves from point A to B under the action of a force, varying in magnitude as shown in the figure. Force is expressed in newton and displacement in meter. What is the total work done?

Three point charges +2, +2, and +5µC are placed respectively at the vertices A, B, C of an equilateral triangle of side 0.2 m. The magnitude of the force experienced by the charge at C is ______.
When one electron is taken towards the other electron, then the electric potential energy of the system ______
