Mass of Electron: Equations & Quantum Physics

[whatisreality]

What are some equations that require the mass of an electron? I'm sure there are thousands, but none spring to mind... Also, is it fair to say that electron mass is an essential quantity in quantum physics?

 

[anorlunda]

How can one rank physical quantities in terms of "essence?" That sounds like pseudo science.

 

[tech99]

What are some equations that require the mass of an electron? I'm sure there are thousands, but none spring to mind... Also, is it fair to say that electron mass is an essential quantity in quantum physics?

I do not have equations to hand but areas where electron mass is required include design of electron guns, CRTs and magnetrons, transit time effects in a vacuum tube and magneto ionic resonance in the ionosphere.