An electron beam is moving between two parallel plates having electric field $1.125 \times {10^{ - 6}}N/m$. A magnetic field $3 \times {10^{ - 10}}T$ is also applied so that beam of electrons do not deflect. The velocity of the electron is ............ $m/s$
$4225$
$3750$
$2750$
$3200$
Cathode rays are produced when the pressure is of the order of
Three particles having their charges in the ratio of $1 : 3 : 5$ produce the same spot on the screen in Thomson’s experiment. Their masses are in the ratio of
The ratio of momenta of an electron and an $\alpha - $particle which are accelerated from rest by a potential difference of $100 V$ is
An electron is moving with constant velocity along $x - $ axis. If a uniform electric field is applied along $y - $ axis, then its path in the $x - y$ plane will be
A charge of magnitude $3e$ and mass $2m$ is moving in an electric field $\overrightarrow E .$ The acceleration imparted to the charge is