Definition

The measure of how well a surface can emit thermal radiation compared to a perfect black surface at the same temperature.

Example

The emissivity of the material affects how efficiently it can radiate heat.

Conversation

I was reading about how different materials have varying emissivity levels.

That sounds interesting! What does that mean exactly?

It basically refers to how effectively a surface can emit heat compared to a perfect blackbody.

Got it! So, the higher the emissivity, the better it is at radiating heat.

Synonyms & Antonyms

Root Explanation

Emissivity is formed from "emittere" (meaning to send out) and the suffix "-ivity" (indicating a quality or state). The word describes the quality of a surface to emit energy, particularly thermal radiation.

Memory Tip

Think of 'sending out' ('emittere') energy, which helps you remember that 'emissivity' refers to the quality of a surface to emit energy.

Visually Confused Words