Explanation

Positive rays, also known as canal rays, are formed when electrons in a discharge tube collide with gas atoms, ionizing them and creating positively charged ions.

These ions then travel towards the cathode and are repelled by it, passing through holes in the cathode to form a stream of positive rays. Since these rays are composed of ions derived from the gas present in the tube,

Their nature is directly determined by the composition of the residual gas within the discharge tube.