Three particles are projected in a uniform electric field with the same velocity perpendicular to the field,as shown in the figure. Which particle has the highest charge-to-mass ratio?

$A$ block of mass $m$ containing a net negative charge $-q$ is placed on a frictionless horizontal table and is connected to a wall through an unstretched spring of spring constant $k$ as shown. If a horizontal electric field $E$ parallel to the spring is switched on,then the maximum compression of the spring is:

$A$ uniform vertical electric field $E$ is established in the space between two large parallel plates. $A$ small conducting sphere of mass $m$ is suspended in the field from a string of length $L$. If the sphere is given a $+q$ charge and the lower plate is charged positively,the period of oscillation of this pendulum is:

In an ink-jet printer,an ink droplet of mass $m$ is given a negative charge $q$ by a computer-controlled charging unit,and then enters at speed $v$ in the region between two deflecting parallel plates of length $L$ separated by distance $d$ (see figure below). All over this region exists a downward electric field $E$ which you can assume to be uniform. Neglecting the gravitational force on the droplet,the maximum charge that can be given so that it will not hit a plate is close to :

In the absence of gravity,a charge $q$ and mass $2m$ is placed stationary in a uniform electric field of intensity $E$. When the charge is released,its speed after $n$ seconds is . . . . . . .

$A$ hot filament liberates an electron with zero initial velocity. The anode potential is $1200 \,V$. The speed of the electron when it strikes the anode is