Gausss Law Physics - Gausss Law

If flux of the electric field through a closed surface is zero:

1. The electric field must be zero everywhere on the surface.
2. The electric field may be zero everywhere in the surface.
3. The charge inside the surface must be zero.
4. The charge in the vicinity of the surface must be zero.

Figure shows a charge q placed at the centre of a hemisphere. A second charge Q is placed at one of the positions A, B, C and D. In which position(s) of this second charge, the flux of the electric field through the hemisphere remains unchanged?

1. A
2. B
3. C
4. D

A closed surface S is constructed around a conducting wire connected to a battery and a switch (figure). As the switch is closed, the free electrons in the wire start moving along the wire. In any time interval, the number of electrons entering the closed surface S is equal to the number of electrons leaving it. On closing the switch, the flux of the electric field through the closed surface:

1. Is increased.
2. Is decreased.
3. Remains unchanged.
4. Remains zero.

A metallic particle having no net charge is placed near a finite metal plate carrying a positive charge. The electric force on the particle will be:

1. Towards the plate.
2. Away from the plate.
3. Parallel to the plate.
4. Zero.

A rubber balloon is given a charge Q distributed uniformly over its surface. Is the field inside the balloon zero everywhere if the balloon does not have a spherical surface?

A point charge q is placed in a cavity in a metal block. If a charge Q is brought outside the metal, will the charge q feel an electric force?

Show that there can be no net charge in a region m which the electric field is uniform at all points.

A charge Q is placed at the centre of a cube. Find the flux of the electric field through the six surfaces of the cube.

Three identical metal plates with large surface areas are kept parallel to each other as shown in figure. The leftmost plate is given a charge Q, the rightmost a charge -2Q and the middle one remains neutral. Find the charge appearing on the outer surface of the rightmost plate.

A charge Q is placed at the centre of an uncharged, hollow metallic sphere of radius a:

1. Find the surface charge density on the inner surface and on the outer surface.
2. If a charge q is put on the sphere, what would be the surface charge densities on the inner and the outer surfaces?
3. Find the electric field inside the sphere at a distance x from the centre in the situations (a) and (b).

Consider the situation of the previous problem:

1. Find the tension in the string in equilibrium.
2. Suppose the ball is slightly pushed aside and released. Find the time period of the small oscillations.