Chapter 12, Problem 8STP

To determine

To choose the correct option: the substance inside a fluorescent bulb which absorbs ultraviolet radiation and emits visible light among the options such as (A) neon (B) tungsten (C) phosphors (D) sodium vapor.

Answer to Problem 8STP

The correct option is (C).

Explanation of Solution

Introduction:

The fluorescent bulbs contain fluorescence and are more efficient than incandescent bulbs. They produce light because of the phosphorous coating.

A fluorescent bulb consists of a glass tube filled with a mixture of mercury vapor and argon. There are metal electrodes at each end which are coated with an alkaline which gives off electrons easily. When current flows through the electrodes, the gas present gets ionized and emits ultraviolet radiation. The inner part of the tube is coated with phosphors. The phosphors absorb ultraviolet radiation and fluorescence emits the energy as visible light.

Conclusion:

Hence, the correct answer is (C).