Question

Among the following statements:

A discharge lamp uses a discharge tube which is filled with a gas at a very low pressure.
Always white light is emitted independent of gas taken in the lamp.

• A. Only 1 is true
• B. Only 2 is true
• C. Both 1 and 2 are true
• D. Both 1 and 2 are false

Hint:

In discharge lamps, the textbfcolour of emitted light depends on the gas filled in the tube, not all discharge lamps emit white light.

Answer 1

The Correct Option is A

Step 1: Examine statement (1). A discharge lamp works by passing electric current through a gas at very low pressure inside a discharge tube (e.g., neon lamp, sodium vapour lamp). Hence, statement (1) is true. Step 2: Examine statement (2). The colour of light emitted by a discharge lamp depends on the type of gas used. For example:

Neon gas → red light
Sodium vapour → yellow light
Mercury vapour → bluish light
Therefore, white light is not always emitted. Statement (2) is false. Step 3: Final conclusion. Only statement (1) is true. \[ \boxed{\text{(A)}} \]