When the pressure of the gas in a discharge tube is gradually lowered. I. there is a violet glow in the tube II. the glow in the tube splits into bands which get further apart. III, the glow and the bands eventually disappear and there is a green fluorescence in the tube. IV. the tube breaks into pieces. Which of the following are correct?
-
A.
I and II only -
B.
I and III only -
C.
I and IV only -
D.
I, II and III only -
E.
I, II III and IV