In which region magnitude of $x$ -component of electric field is maximum, if potential $(V)$ versus distance $(X)$, graph is as shown?

Electric potential at any point is $V = - 5x + 3y + \sqrt {15} z$, then the magnitude of the electric field is

A cathode ray tube contains a pair of parallel metal plates $1.0\, cm$ apart and $3.0\, cm$ long. A narrow horizontal beam of electron with a velocity $3 \times 10^7\, m/s$ passed down the tube midway between the plates. When a potential difference of $550\, V$ is maintained across the plates, it is found that the electron beam is so deflected that it just strikes the end of one of the plates. Then the specific charge of the electron in $C/kg$ is

A particle $A$ has charge $+q$ and particle $B$ has charge $+ 4q$ with each of them having the same mass $m$. When allowed to fall from rest through same electrical  potential difference, the ratio of their speed $V_A : V_B$ will be :-

An electron enters between two horizontal plates separated by $2\,mm$ and having a potential difference of $1000\,V$. The force on electron is

The figure gives the electric potential $V$ as a function of distance through five regions on $x$-axis. Which of the following is true for the electric field $E$ in these regions