The above figure shows equipotential surfaces in an electric field. At which of the points $X$, $Y$ and $Z$ is the magnitude of the electric field the highest? Why?

Identify the part of the electromagnetic spectrum represented by the following wavelengths and arrange them in the descending order of their wavelengths.

$l_1$- produced by bombarding a metal target with high energy electrons.

$l_2$- produced by klystron and magnetron valves.

$l_3$- produced by vibrations of atoms and molecules.

A cube of side length $‘l’$, encloses a charge $‘q’$ placed at its centre as shown in the figure. What is the flux linked with one face of the cube? The plane of a square of side $10 \mathrm{cm}$ makes an angle of $30°$ with the direction of an electric field, whose magnitude is $4\times {10}^3 \mathrm{N}/\mathrm{C}$. Determine the flux through the square.

With the help of a diagram, obtain an expression for the electric field at a point outside a charged thin spherical shell. The figure shows four positively charged particles. A Gaussian surface enclosesq1  and q2  :

What is the net electric flux through the Gaussian surface ?

With the help of a diagram, obtain an expression for the electric field at a point outside a charged thin spherical shell. The figure shows four positively charged particles. A Gaussian surface enclosesq1  and q2  :

Which of the particles shown, contribute to the electric field at point P on the surface.

With the help of a diagram, obtain an expression for the electric field of an electric dipole at a point on its equatorial plane. The figure shows an electric dipole placed along the X-axis in an external non-uniform electric field, increasing in + x-direction

 What is the direction of the force experienced by the charge $(-q)$ ?

With the help of a diagram, obtain an expression for the electric field of an electric dipole at a point on its equatorial plane. The figure shows an electric dipole placed along the X-axis in an external non-uniform electric field, increasing in + x-direction

What is the direction of the net force experienced by the dipole ?