An electron enters a region of uniform electric field with an initial velocity of $30 \mathrm{km} {\mathrm{s}}^{-1}$ in the same direction as the electric field which has magnitude, $E=50 \mathrm{N} {\mathrm{C}}^{-1}$.

(a) What is the speed of the electron$1.5 \mathrm{ns}$ after entering this region?
(b) How far does the electron travel during the $1.5 \mathrm{ns}$ interval?

 In Fig, particle $1$ of charge $q_1=-4.00q$ and particle $2$ of charge ${\mathrm{q}}_2=+2.00 \mathrm{q}$ are fixed to an $x$ axis. $\left(\mathrm{a}\right)$ As a multiple of distance $\mathrm{L},$ at what coordinate on the axis is the net electric field of the particles zero? $\left(\mathrm{b}\right)$ Sketch the net electric field lines between and around the particles.

A certain electric dipole is placed in a uniform electric field $\overrightarrow{E}$ of magnitude $40 \mathrm{N} {\mathrm{C}}^{-1}$ . Figure (given below) gives the magnitude $\tau$ of the torque on the dipole versus the angle$\text{ θ}$ between field $\overrightarrow{E}$ and the dipole moment $\overrightarrow{p}$ . The vertical axis scale is set by ${\tau }_{\mathrm{s}}=80\times {10}^{-28} \mathrm{N} \mathrm{m}$. What is the magnitude of $\overrightarrow{P}?$