# e/m ratio

#### logearav

Joined Aug 19, 2011
243
The e/m is not constant for
A) cathode rays B) positive rays C) alpha rays D) beta rays
Surely cathode rays and beta rays is not the answer, because they consists of electrons. Positive rays are hydrogen ions and alpha rays are helium nuclei. So i presume positive rays or alpha rays is the right answer. But I am not sure. So, learned members' views are welcome

#### Kermit2

Joined Feb 5, 2010
4,163
An electron which has a high velocity due to acceleration, like those in a cathode ray tube, will have increased mass due to the additional kinetic energy imparted to the particle. Remember Einsteins famous equation of E=mc(squared). So electrons can indeed have variations in their em ratios

#### Papabravo

Joined Feb 24, 2006
12,767
Based on the mass and the low probability of achieving a relativistic velocity I'll go with the alpha particle.

#### Kermit2

Joined Feb 5, 2010
4,163
Papa is right on this one I believe. Further thought suggests the Alpha would be the right choice since it can come in two atomic configurations; 2Protons 1Neutron, and 2Protons 2Neutrons, as well as other less common isotopes