Which thermometer type is used to measure surface temperature?

• A. Thermocouple
• B. Infrared/laser
• C. Digital Bi-metallic
• D. Bi-metallic

Answer: (B)

Measuring surface temperature is best done with a device that detects the heat radiating from the surface rather than touching it. An infrared thermometer does exactly that: it senses infrared energy emitted by the surface and converts it into a temperature reading. The built-in laser pointer helps you aim at the exact spot, which makes it fast, non-contact, and ideal for surfaces that are hot, moving, or hard to reach.

Other types rely on contact. A thermocouple needs a probe tip touching the surface to read its temperature, which can be impractical for quick surveys or delicate surfaces. Bi-metallic devices, whether standard or digital, also require contact and respond more slowly, offering less precision for surface quick checks.

Be mindful that infrared readings can be influenced by how the surface reflects heat, its emissivity, and cleanliness, so adjust the emissivity setting and aim for a clean, representative spot for best accuracy.