Question

When the pressure of a gas in a discharge tube is reduced from 5 mm to 0.05 mm of Mercury the anode glow:

• A. becomes smaller
• B. become bigger
• C. becomes smaller and breaks into smaller diselets
• D. does not change

Answer 1

The correct option is A

becomes smaller

Explanation for the correct option:

1. When the pressure of a gas in a discharge tube is reduced from 5 mm to 0.05 mm of Mercury the anode glow becomes smaller and breaks into small dancing disclets called striations.
2. The negative glow moves towards the anode.

Hence, option (A) is the correct option.