Physical electrostatic balance, what is the principle of electrostatic equilibrium?

A bit of a physics contest!

b is grounded first, and the electric potential on the b spherical shell is 0;

The electric potential on b is calculated u=kq r+k*q1 r

r is the radius of b, q1 is the charge of b at this time), bring in u=0, q1=-q;

Then A is grounded, and the surface potential of ball A is 0;

The electric potential on a is calculated as u=k*q1 r+k*q2 rq2 is the charge charge of a at this time, and r is the radius of a).

PS: It should be noted that the internal potential of the spherical shell is equal to the surface potential of the spherical shell, and the potential produced by B on the surface of A should be K*Q1 R, not divided by R).

Bring in u=0 to get q2=(r*q) r

There are 14 days and 6 hours left until the end of the issue.

Reward points: 10 - There are 14 days and 23 hours left before the end of the problem, there is a metal ball with Q in a metal sphere shell with a Q charge, after reaching the electrostatic balance, connect B to the ground and disconnect it, and then connect A to the ground, find the charge of the metal ball A and the inner and outer surfaces of B (you need to assume the radius).

Question addendum: The picture is a metal ball holding a spherical shell on the outside, (concentric, the two do not touch), such a picture should be able to draw by looking at the title.

After the electrostatic equilibrium is reached, the inner surface of the spherical shell is charged with -q, and the outer surface is charged with q+q.

After the spherical shell is grounded, the charge on the outer surface becomes 0, and the others remain unchanged.

At this time, the spherical shell is disconnected from the ground, the ball is charged q, and the whole spherical shell is charged -q, which is distributed on the inner surface, and the outer surface is not charged.

Then the ball is grounded, the ball charge becomes 0, and the total charge of the spherical shell remains unchanged, which is -q.

The principle of electrostatic equilibrium is as follows:

Electrostatic equilibrium is when the charge in the guide body is in a steady state. The condition for a homogeneous conductor to reach electrostatic equilibrium is that the combined field strength inside the conductor is zero everywhere. The state in which there is no directional movement of charges in a conductor (including the surface) is called the state of electrostatic equilibrium.

Inside the metal conductor there are free charges that can move arbitrarily, and these charges are doing random thermal motion. If there is no external force, the whole conductor is electrically neutral. When an electric field is added around the conductor.

When the charge is subjected to a constant external force, the free charge will move directionally, and the conductor will be positively charged at one end and negatively charged at the other. We call the redistribution of the electric charge in a conductor under the action of an external electric field electrostatic induction. The charge on a conductor due to induction is called induced charge.

The characteristic of a conductor is that it has a free moving charge, and these free charges will move in a directional motion after being stressed in an electric field, while "static level liquid quiverbet" refers to the state in which the force on the free charge in the conductor reaches equilibrium and no longer moves directionally.

1. The internal field strength of a conductor in electrostatic equilibrium is zero.

2. The field strength of a conductor in electrostatic equilibrium at any point near its outer surface is perpendicular to the surface of that point.

3. The whole conductor in the electrostatic equilibrium state is an equipotential body, and its surface is an equipotential surface. The earth is a very large conductor and can be considered to be in electrostatic equilibrium, so it is an equipotential body.

4. The internal charge density of the conductor in the electrostatic equilibrium is zero everywhere (the failure is proved by Gauss's theorem).

5. The charge on the conductor in electrostatic equilibrium can only exist on the surface of the conductor.

Electrostatic equilibrium is when the charge in the guide body is in a steady state. The condition for a homogeneous conductor to reach electrostatic equilibrium is that the combined field strength inside the conductor is zero everywhere. The state in which there is no directional movement of charges in a conductor (including the surface) is called the state of electrostatic equilibrium.