In Thomson spectrograph experiment, four positive ions $P,Q,R$ and $S$ are situated on $Y-X$ curve a shown in the figure
The specific charge of $R$ and $S$ are same
The masses of $P$ and $S$ are same
The specific charges of $Q$ and $R$ are same
The velocities of $R$ and $S$ are same
The fact that electric charges are integral multiples of the fundamental electronic charge was proved experimentally by
The current conduction in a discharged tube is due to
An oxide coated filament is useful in vacuum tubes because essentially
Cathode rays are produced when the pressure is of the order of
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