In the phenomenon of electric discharge through gases at low pressure, the coloured
glow in the tube appears as a result of
(1) Collision between different electrons of the atoms of the gas
(2) Excitation of electrons in the atoms
(3) Collision between the atoms of the gas
(4) Collisions between the charged particles emitted from the cathode and the atoms of
the gas
Sol. Answer (2)
Due to excitation of electrons in atoms.