Hii Riya!
The anode rays do not originate from cathode as well as anode too. They are produced in between the two. It is believed that the rays are produced as a result of knockout of electrons from the gaseous atom, by bombardment of high speed electrons of cathode ray. Thus, te rays are produced between the Space of anode and cathode. As the size of electrons and the other nucleons differ for each gas, Thus, it is said that they depend on the nature If the gas. Hope this helps.
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