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A charge Q is uniformly distributed over a large plastic plate. The electric field at a point P close to the centre of the plate is 10 V m–1. If the plastic plate is replaced by a copper plate of the same geometrical dimensions and carrying the same charge Q, the electric field at the point P will become
Figure shows an imaginary cube of edge L/2. A uniformly charged rod of length L moves towards left at a small but constant speed v. At t = 0, the left end just touches the centre of the face of the cube opposite it. Which of the graphs shown in figure represents the flux of the electric field through the cube as the rod goes through it?
A closed surface S is constructed around a conducting wire connected to a battery and a switch. 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.
The radius of a gold nucleus (Z = 79) is about 7.0 × 10–15 m. Assume that the positive charge is distributed uniformly throughout the nuclear volume. Find the strength of the electric field at
(a) the surface of the nucleus and
(b) at the middle point of a radius.
Remembering that gold is a conductor, is it justified to assume that the positive charge is uniformly distributed over the entire volume of the nucleus and does not come to the outer surface?
A charge Q is placed at the centre of an uncharged, hollow metallic sphere of radius a.
(a) Find the surface charge density on the inner surface and on the outer surface.
(b) If a charge q is put on the sphere, what would be he surface charge densities on the inner and the outer surfaces?
(c) Final the electric field inside the sphere at a distance x from the centre in the situations (a) and (b).
Consider the following very rough model of a beryllium atom. The nucleus has four protons and four neutrons confined to a small volume of radius 10–15 m. The two 1s electrons make a spherical charge cloud at an average distance of 1.3 × 1011 m from the nucleus, whereas the two 2s electrons make another spherical cloud at an average distance of 5.2 × 10–11 m from the nucleus. Find the electric field at
(a) a point just inside the 1s cloud and (b) a point just inside the 2s cloud.
One end of a 10 cm long silk thread is fixed to a large vertical surface of a charged nonconducting plate and the other end is fastened to a small ball having a mass of 10 g and a charge of 4.0 × 10–6 C. In equilibrium, the thread makes an angle of 60° with the vertical. Find the surface charge density on the plate.
Two conducting plates X and Y, each having large surface area A (on one side), are placed parallel to each other as shown in figure. The plate X is given a charge Q whereas the other is neutral. Find:
(a) the surface charge density at the inner surface of the plate X,
(b) the electric field at a point to the left of the plates
(c) the electric field at a point in between the plates and
(d) the electric field at a point to the right of the plates