Question

For advertisement, the coloured discharge tubes contain

• A. Ne
• B. Ar
• C. Be
• D. Kr

Hint:

Neon lights = discharge through \textbf{Ne at low pressure}.

Answer 1

The Correct Option is A

Step 1: Coloured discharge tubes used in advertisements are filled with noble gases.
Step 2: Each gas gives characteristic color due to electronic transitions.
Step 3: Neon is most commonly used because: - It emits intense orange-red light, - It works at low pressure and voltage, - It is chemically inert and inexpensive.
Step 4: Other gases are used rarely for special shades; the standard is neon.