The effect of corona can be detected by___________?
A. presence of ozone detected by odour
B. hissing sound
C. faint luminous glow of bluish colour
D. all of the above
The effect of corona can be detected by___________?
A. presence of ozone detected by odour
B. hissing sound
C. faint luminous glow of bluish colour
D. all of the above