A charged ball B hangs from a silk thread S, which makes an angle `theta` with a large charged conducting sheet P as shown in Fig. Show that the surface charge density of the sheet is proportional to `tan theta`.

If a small sphere of mass m and charge q hangs from a silk thread at angle theta with a charged coducting plate, show that the equilibrium of the sphere, the surface charge density for the plate is epsilon_0 = (mg)/q tan theta

A 1 mg ball carrying a charge of 2xx10^-8 C hangs from a thread. When a large conducting plate of charge is brought near the ball, the thread makes an angle of 30^@ with the plate. What is the surface charge density of the plate?

In 1959 Lyttleton and Bondi suggested that athe expansion of the Universe could be expalined if matter carried a net charge. Suppose that the Universe is made up of hydrogen atoms with a number density N, which is maintained a constant. Let the charge on the proton be: e_p = -(1+y)e , where e is the electronic charge. show that the velocity of expansion is proportional to the distance from the centre.

A positivity charges ball hangs from a silk thread Electric filed at a certain point (at the same horizontal level of ball) due to this charge is E.. We put a positive test charge Q_0 at a point and measure F//q_0 then, it can be prediced that the electric field strength E

A test charge q is moved without acceleration from A to C along the path from the point A to B and then from B to C in electric field as shown in fig. At which point( of the two) is the electric potential more and why?

Two small charged metal sphere A and B are situated in a vaccum. The distance between the centres of the spheres is 12.0 cm, as shown in the fig. The charge on each sphere may be assumed to be a point charge at the centre of the sphere. Point P is a movable point that lies on the line joining the centres of the sphere and is distance x fromt he centre of sphere A. The variation with distance x fo the electric field strength E at point P as shown in the figure. Use fig to state and explain the distance x at which the rate of change of potential with distance is maximum and minimum.

Two large flat parallel sheets A and B having a uniform charge density + sigma are held as shown in the figure. Graphically, represent the variation of electric field due to the two sheets as one moves from the point O to P.

Light from an ordianry source(say a sodium lamp) is passed through a polaroid sheet P_1 .The transmitted light is then made to pass through a second polaroid sheet P_2 ,which can be rotated so that the angle (theta) betwen the two polaroid sheets varies from 0^@ to 90^@ .Show graphically the variation of he intensity of light transmitted by P_1 and P_2 as a function of the angle theta .Take the incident beam intensity as I_0 . Why does the light from a cleear blue portion of the sky,show a rise and fall on intesnity,when viewed through a polaroid ,which is rotated?

Two large flat parallel sheets A and B having uniform surface charge densities sigma and -sigma are held as shown in the figure graphically, represent the variation of electric field due to the two sheets as one move from the point O to P.

A conductor A with a cavity as shown in Fig. is given a charge Q.. Another conductor B with charge q is inserted into the cavity keeping B insulated from A. Show that the total charge on the outside surface of A is Q + q .