An $\alpha$ particle is accelerated through a p.d of ${10^6}$ volt then $ K.E$ . of particle will be .......... $MeV$
$ 8$
$ 4 $
$ 2 $
$ 1$
An electron is accelerated through a potential difference of $200$ volts. If $e/m$ for the electron be $1.6 \times {10^{11}}$ $coulomb/kg$ , the velocity acquired by the electron will be
$1$ $J$ is equal to how many electron volt?
Who produced electromagnetic waves for the first time ?
In a Millikan's oil drop experiment the charge on an oil drop is calculated to be $6.35 \times {10^{ - 19}}C$. The number of excess electrons on the drop is
The cathode rays have particle nature because of the fact that