How are electrons accelerated in electron gun of cathode ray tube?

The electron gun was the source of the electrons, which, when heated and formed into a beam, were directed to differing parts of the screen by magnetic fields surrounding the envelope

joseph Thomson

Because -- they are?Or, more specifically, because the particles within cathode rays act exactly like electrons. They either ARE electrons or they do a REAL good job of imitating them.

J.J. Thomsan

J.J Thomson