What Makes Incandescent Lamps Glow?

Which type of lamp runs electrical current through tungsten, heating it up and making it glow, often coiled to increase the length of the filament?

a) Fluorescent lamp b) Halogen lamp c) Incandescent lamp d) LED lamp

Final answer: The incandescent lamp runs electrical current through a tungsten filament, heating it up and causing it to glow, creating light.

Explanation: The type of lamp that runs electrical current through a tungsten filament, heating it up and causing it to glow, is the incandescent lamp. This is a simple design where the tungsten filament is often coiled to increase the length of the filament and is placed in a partially evacuated glass envelope. The operation principle of the incandescent lamp involves running current through the filament. The temperature of the filament then becomes large enough to cause it to glow and produce light. The two ends of the filament are attached to contacts which are separated by an insulating material.

The other types of lamps mentioned, the fluorescent lamp and LED lamp, operate differently. Fluorescent lamps house argon and mercury vapor within a spiral-shaped tube. The enclosed gas mixture becomes excited by an electric current, emitting ultraviolet (UV) light which stimulates the fluorescent coating on the inside of the tube, producing visible light. On the other hand, LED (Light Emitting Diodes) emit light when an electric current passes through them, due to the movement of electrons in the semiconductor material.

Incandescent lamps emit more heat compared to these options, resulting in a lower energy efficiency.