Cathode rays enter into a uniform magnetic field perpendicular to the direction of the field. In the magnetic field their path will be
Straight line
Circle
Parabolic
Ellipse
Cathode rays are
The mass of the electron varies with
An $\alpha$ particle is accelerated through a p.d of ${10^6}$ volt then $ K.E$ . of particle will be .......... $MeV$
In Bainbridge mass spectrograph a potential difference of $1000 V$ is applied between two plates distant $1$ cm apart and magnetic field in $B = 1T$. The velocity of undeflected positive ions in m/s from the velocity selector is
Order of q/m ratio of proton, $\alpha $ -particle and electron is