Question

(b) Fluorescent lamps are much more efficient than traditional incandescent bulbs. The explanation lies in the way each produces light. When light is produced by the incandescent bulbs, electrical energy passes through a wire, heating it until glows. The wire, called a filament, typically is made of tungsten. The enclosing bulbs around the filament directs or diffuses the light. The problem is that 90% of the energy put into such a bulb is released in the form of heat while only 10% results in light. Fluorescent lamps produce light in a different way, by energizing gas. Electrical energy flows into electrodes at the ends of the tube. The electrodes emit electrons, which energize a small amount of mercury vapor held at very low temperatures inside the tube. The energized mercury molecules radiate ultraviolet light, which in turn absorbed by a phosphorescent coating on the inside of the surface of the tube, thus producing visible light. This process produces very little heat; fluorescent lamps are able to convert almost 90% of the energy they consume into light.
Thus, the amount of electrical energy required by a fluorescent lamp to produce a given amount of light is substantially less than that required by incandescent bulbs.

Answer these typed not handwritten

(1)What is being explained? (Title needed) (put a title to topic)
(2)What is the explanation? (Summary of your own)
(3)What conclusion can be drawn about the above explanation? (Your point of view)

Answer 1

ANSWER

(1) TITLE:

Fluorescent Lamps vs Incandescent Lamps

(2) EXPLANATION/SUMMARY :

In case of an incandescent lamp electricity passes through the filament which offers resistance to the electricity & converts electrical energy into heat. This glowing heat makes the filament white hot, which emerged as light. The basic difficulty with incandescent light bulbs is that the generated heat consumes a lot of electrical energy (Almost 90% of input energy is released as heat).

On the other hand, fluorescent lights are produced by ionizing gases(Mercury or Argon) filled in a tube. Electrodes are placed at both ends of a fluorescent tube & held at a low temperature . With the flow of electricity electrons flow through the gas from one electrode to the other. These electrons in turns excite the mercury atoms. As the mercury atoms stabilize back to its ground state, they release ultraviolet light, which is absorbed by a phosphorescent coating , thus producing visible light. Thus, this process produces very little heat (Almost 90% of the input energy converted into light).

That's why fluorescent lamps are much more efficient than traditional incandescent bulbs.

(3) CONCLUSION:

Fuorescent lamps have greater efficiency & longer life time than that of a regular incandescent lamp. However fluorescent Lamps are slightly more expensive.

The major problem with the fluorescent lamp is the presence of toxic gases (mercury) inside fluorescent lamps . If a fluorescent lamp is broken, the released mercury gas can contaminate the surrounding environment.