Red Seal Industrial Electrician Practice Exam

Which of the following is an example of a high-intensity discharge (HID) lighting type?

1. Compact fluorescent

2. Metal halide

3. Incandescent

4. LED

The correct answer is: Metal halide

Metal halide is classified as a high-intensity discharge (HID) lighting type due to its design and the way it produces light. HID lights work by passing an electric current through a gas. In the case of metal halide lamps, the gas contains metal halide salts which help produce a bright, white light that has a high lumen output. This makes them particularly suitable for applications like street lighting, sports facilities, and large commercial spaces where high brightness levels are required. In comparison, compact fluorescent and incandescent lights operate on different principles. Compact fluorescent bulbs utilize a gas and phosphor coating to emit light, but they do not reach the same intensity as HID lighting. Incandescent bulbs generate light by heating a filament until it glows, which is inherently less efficient and produces significantly less light output than HID types. LED lighting also produces light differently, relying on semiconductor technology, and while LEDs can be very efficient, they are not categorized as HID lights.