The two main advantages of fluorescent lamp over filament lamp are :
- Fluorescent lamp produces more lamp even with same power.
- fluorescent lamp has longer lifespan in comparison to filament lamp.
A fluorescent lamp consists of a glass tube filled with a mixture of argon and mercury vapour. Metal electrodes at each end are coated with an alkaline earth oxide that gives off electrons easily. When current flows through the gas between the electrodes, the gas is ionized and emits ultraviolet radiation.A fluorescent lamp generates light from collisions in a hot gas ('plasma') of free accelerated electrons with atoms– typically mercury – in which electrons are bumped up to higher energy levels and then fall back while emitting at two UV emission lines (254 nm and 185 nm).Fluorescent lamps give light from a large glowing surface rather than a small intense source. These lamps are commonly used in situations which call for general illumination at an even level such as offices, classrooms, retail stores, hallways, and cafeterias.
A filament lamp is a common type of light bulb. It contains a thin coil of wire called the filament. This heats up when an electric current passes through it, and produces light as a result. The resistance of a lamp increases as the temperature of its filament increases.The graph is a curve which indicates that V is not directly proportional to I. Therefore, it does not obey Ohm's Law. When the current flows through the filament, its temperature increases. This causes its resistance to increase.