Florescent bulbs come in a range of colors. They herald the new age of the light bulb. The operation of florescent bulbs is based on the knowledge of how atoms behave when they are energized. This basic knowledge is used in all types of light bulbs. An atom comprises of a nucleus and electrons. The electrons orbit the nucleus in different energy levels. When an atom is excited either due to heat (in case of incandescent bulbs) or some other technique, the electrons leap to a higher energy level, further away from the nucleus. The newly acquired energy in the electrode makes it unstable, and it emits this acquired energy in form of light photons. The photons may be of various colors depending on the energy released.

In a fluorescent bulb there are two electrodes inside the glass enclosure. The electrodes are connected to an AC current circuit. A small amount of mercury is also placed inside the glass bulb, apart from an inert gas at low pressure. The inner side of the glass enclosure is coated with phosphorous. When a current is passed through the electrodes and it is heated up, the excited electrodes move in the glass enclosure and some of them collide with mercury traces. The mercury becomes gaseous, and some of the charged atoms or electrons collide with the gaseous mercury and become further charged. The highly charged electrons, which are also highly unstable, release the photons. Most of the light energy released is in the form of ultraviolet rays, which are invisible to human eyes. The phosphorus which is coated on the inside of the bulb glows to produce visible light when the ultraviolet rays fall on them. Different combinations of photon coatings produce lights of different colors.

Florescent bulbs are more efficient than ordinary incandescent bulbs. They produce more light for the same current as incandescent lamps. Thus, with lower currents they produce a similar intensity of light as incandescent bulbs, and are energy-efficient. They can offer a variety of color ranges unavailable in other light bulbs. As they are not affected by vibration, fluorescent bulbs can be safely used as fan bulbs. Fluorescent bulbs do not become blistering hot, and can be used in places where fire safety is a concern.