Two small spheres, each of mass $m$, are suspended by light strings of length $l$ as shown in the figure. A uniform electric field is applied in the $\mathrm{X}$– direction. The spheres have charges equal to $-q$ and $+q$. Determine the electric field that enables the spheres to be in equilibrium at an angle of $\theta$.

Two pieces of plastic, a full ring and a half ring, have the same radius and charge density. Which electric field at the centre has the greater magnitude? Define your answer.

Two semi-circular wires $ABC$ and $ADC$, each of radius $R$, are lying on $x-y$ and $x-z$  planes, respectively, as shown in the figure. If the linear charge density of the semi-circular parts and straight parts is $\mathrm{\lambda }$, find the electric field intensity $\overrightarrow{E}$ at the origin.

An infinite wire having linear charge density $\lambda$ is arranged as shown in the figure. A charge particle of mass $m$ and charge $q$ is released from point $P$. Find the initial acceleration of the particle (at $t=0$) just after the particle is released.

Is an electric field of the type shown by the electric lines in the figure physically possible?

Figure shows three electric field lines.

At which point, $\mathrm{A}$ or $\mathrm{B}$, will the acceleration of the test charge be greater if the charge is released?

Figure shows that $E$ has the same value for all points in front of an infinitely charged sheet. Is this reasonable? One might think that the field should be stronger near the sheet, because the charges are so much closer