In a cathode ray experiment hydrogen gas was subjected to very low pressure and high voltage. The $\frac{e}{m}$ of cathode rays liberated was $-x~C~kg^{-1}$. In the second experiment helium gas was used under the same experimental conditions. What is the $\frac{e}{m}$ $(in~C~kg^{-1})$ of cathode rays liberated in the second experiment?}
Show Hint
Cathode rays are electrons. Their charge-to-mass ratio is always the same regardless of the gas inside the discharge tube.