Calculate the work done to dissociate the system of three charges placed on the vertices of a triangle, as shown in Fig. 2.38. Here $q=1.6\times {10}^{-10}C.$

    

 

     

 

   

What is the electrostatic potential energy of the charge configuration shown in Figure?

Take $q_1=+ 1.0\times {10}^{-8} \mathrm{C}, q_2=- 2.0\times {10}^{-8}\mathrm{ }\mathrm{C},q_3=+ 3.0\times {10}^{-8} C,q_4=+ 2.0\times {10}^{-8}\mathrm{ }\mathrm{C}$ and $a=1.0$metre.

Three-point charges $+ q,+2q$ and $Q$ are placed at the three vertices of an equilateral triangle. Find the value of charge $Q$ (in terms of  $q$), so that electric potential energy of the system is zero.

 An electron (charge $=-e$) is placed at each of the eight corners of a cube of side $a$and an $\alpha$-particle (charge $=+2e$) at the centre of the cube. Calculate the potential energy of the system.

[3 Marks]

Two identical particles, each having a charge of $2.0\times {10}^{-4}\mathrm{ }\mathrm{C}$ and mass of $10\mathrm{ }\mathrm{g}$, are kept at a separation of $10 \mathrm{cm}$ and then released. What would be the speeds of the particles when the separation becomes large?

Find the amount of work done in rotating an electric dipole, of dipole moment $3.2\times {10}^{-8}\mathrm{ }\mathrm{Cm}$. from its position of stable equilibrium to the position of unstable equilibrium, in a uniform electric field of intensity ${10}^4\mathrm{ }\mathrm{N}/\mathrm{C}.$

An electric dipole consists of two opposite charges each of magnitude $1 \mu \mathrm{C}$ separated by  $2\mathrm{ }\mathrm{cm}.$ The dipole is placed in an external electric field of ${10}^5\mathrm{N}\mathrm{ }{\mathrm{C}}^{-1}.$ Find i   the maximum torque exerted by the field on the dipole ii  the work which the external agent will have to do in turning the dipole through ${180}^o$ starting from the position $\theta =0^o$

Find the capacitance of a conducting sphere of radius $10\mathrm{ }\mathrm{cm}$situated in air. How much charge is required to raise it to a potential of $1000$ volt?

Assuming the earth to be a spherical conductor of radius $6400\mathrm{ }\mathrm{km}$, calculate its capacitance.