**Absorptive power** of a body for a given wavelength and temperature is defined as the ratio of the radiant energy absorbed per unit area per unit time to the total energy incident on it per unit area per unit time.

**It is denoted by a _{λ}. **

**Absorptive power** of a body for a given wavelength and temperature is defined as the ratio of the radiant energy absorbed per unit area per unit time to the total energy incident on it per unit area per unit time.

**It is denoted by a _{λ}. **