Gas Fitter Practice Test

What is the function of the mantle of a gas lamp?

1. Provides ignition

2. Mixes air and gas

3. Protects the igniter

4. Changes a blue flame to a luminous flame

The correct answer is: Changes a blue flame to a luminous flame

The mantle of a gas lamp serves the purpose of changing a blue flame into a luminous flame. When the gas burns, it produces a blue flame that is typically less visible and does not emit as much light. The mantle is made from a material that, when heated, glows brightly, thereby increasing the overall light output of the flame. This is achieved through a process known as incandescence, where the high temperature of the mantle causes it to emit light in the visible spectrum. The combustion of gas within the lamp generates heat, which is essential for the mantle's glowing effect. As the gas burns and the flame heats the mantle, it transforms the energy from the blue flame into a bright yellow or white light. This property is what makes gas lamps effective lighting sources compared to those that produce only a blue flame without a mantle. In the context of the other functions described, while ignition and the mixing of air and gas are critical components of a gas lamp's operation, they do not specifically relate to the mantle itself. The mantle does not protect the igniter; instead, its primary role is focused on enhancing the visibility of the flame produced by the burning gas. Thus, the mantle's ability to emit a luminous glow is what makes it