How do emissivity and temperature affect the amount of infrared radiation emitted by an object?

How do emissivity and temperature affect the amount of infrared radiation emitted by an object?

• A. Low Emissivity and High Temperature Emit More Radiation
• B. High Emissivity and High Temperature Emit More Radiation
• C. High Emissivity and Low Temperature Emit More Radiation
• D. Emissivity and Temperature Do Not Affect Emission

Answer: (B)

The amount of infrared radiation an object emits depends on two factors: how well its surface radiates (emissivity) and its temperature. According to the Stefan-Boltzmann relationship, the radiant exitance M is M = ε σ T^4, where ε is emissivity, σ is the Stefan-Boltzmann constant, and T is the absolute temperature. This means that increasing emissivity increases emission directly, and increasing temperature increases emission very strongly because of the T^4 term. So the most infrared radiation comes from an object that is a good emitter (high emissivity) and is hot (high temperature).

The amount of infrared radiation an object emits depends on two factors: how well its surface radiates (emissivity) and its temperature. According to the Stefan-Boltzmann relationship, the radiant exitance M is M = ε σ T^4, where ε is emissivity, σ is the Stefan-Boltzmann constant, and T is the absolute temperature. This means that increasing emissivity increases emission directly, and increasing temperature increases emission very strongly because of the T^4 term. So the most infrared radiation comes from an object that is a good emitter (high emissivity) and is hot (high temperature).