Acceleration of a charged particle of charge $q$ and mass $m$ moving in a uniform electric field of strength $E$ is

$A$ charged oil drop is suspended in a uniform electric field of $3 \times 10^{4} \; V/m$ so that it neither falls nor rises. The charge on the drop will be $..... \times 10^{-18} \; C$. (Take the mass of the drop $= 9.9 \times 10^{-15} \; kg$ and $g = 10 \; m/s^{2}$)

$A$ small point mass carrying some positive charge is released from the edge of a table. There is a uniform electric field in this region in the horizontal direction. Which of the following options correctly describes the trajectory of the mass? (Curves are drawn schematically and are not to scale).

An oil drop having a mass $4.8 \times 10^{-13} \,kg$ and charge $2.4 \times 10^{-18} \,C$ stands still between two charged horizontal plates separated by a distance of $1 \,cm$. If now the polarity of the plates is changed,the instantaneous acceleration of the drop is: $(g = 10 \,m/s^2)$ (in $\,m/s^2$)

$A$ particle of mass $M$ and charge $q$ is released from rest in a region of uniform electric field of magnitude $E$. After a time $t$,the distance travelled by the charge is $S$ and the kinetic energy attained by the particle is $T$. Then,the ratio $T/S$:

Two charged particles of masses in the ratio $1: 3$ have charges in reciprocal ratio as their masses. They are placed in a uniform electric field and allowed to move. The ratio of their kinetic energies is